Design Manual for Roads and Bridges
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
Drainage
Inspection & Assessment
CS 551
Drainage surveys
(formerly SD 15/03)
Version 1.0.0
Summary
This document contains the requirements for highway drainage surveys.
Application by Overseeing Organisations
Any specific requirements for Overseeing Organisations alternative or supplementary to those given in this document
are given in National Application Annexes to this document.
Feedback and Enquiries
Users of this document are encouraged to raise any enquiries and/or provide feedback on the content and usage
of this document to the dedicated National Highways team. The email address for all enquiries and feedback is:
Standards_Enquiries@highwaysengland.co.uk
This is a controlled document.
CS 551 Version 1.0.0
Contents
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
Contents
Release notes
6
Foreword
Publishing information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contractual and legal considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7
7
7
Introduction
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Assumptions made in the preparation of this document . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mutual recognition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
8
8
8
Abbreviations
9
Terms and definitions
10
1. Scope
Aspects covered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use of GG 101 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Health and safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
13
13
13
13
2. General requirements
Scope of works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
15
3. Validation survey
Survey requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data round-tripping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Method of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Termination of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality control requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surveyor competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey method quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Photographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
17
17
17
17
18
18
19
19
19
19
19
19
19
4. Priority asset survey
Survey requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data round-tripping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Desk study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Method of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality control requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surveyor competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey method quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Photographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
21
21
21
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24
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24
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25
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CS 551 Version 1.0.0
Contents
5. Filter drain condition survey by GPR
Survey requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data round-tripping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Method of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interruption of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Abandonment of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality control requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surveyor competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey method quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Photographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26
26
26
26
27
27
27
28
28
28
28
29
29
29
32
33
6. All assets condition and connectivity survey
Survey requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data round-tripping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Desk study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Method of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interruption of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality control requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surveyor competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey method quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Photographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
34
34
34
34
35
35
36
38
39
39
39
40
40
40
40
7. Pipework and chambers defect survey by CCTV
Survey requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data round-tripping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Method of survey - pipework CCTV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Method of survey - chambers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interruption of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Abandonment of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality control requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surveyor competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey method quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CCTV picture quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Video recordings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Photographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CAD drawing files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
41
41
41
42
42
43
44
45
46
46
46
47
47
48
48
49
50
50
50
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CS 551 Version 1.0.0
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8. Pipework geometric survey by laser profiler
Survey requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data round-tripping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Method of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interruption of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Abandonment of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality control requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surveyor competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey method quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CAD drawing files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
51
51
51
51
51
51
52
52
52
52
52
52
52
52
53
53
9. Pipework inclination survey
Survey requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data round-tripping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Method of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interruption of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Abandonment of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality control requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surveyor competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey method quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
54
54
54
54
54
54
55
55
55
55
55
56
56
56
56
10. Chambers defect and geometric survey by laser scanner
Survey requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data round-tripping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Method of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interruption of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Abandonment of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality control requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surveyor competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey method quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Video recordings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Photographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unwrapped panoramic photographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CAD drawing files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
58
58
58
58
59
60
60
61
61
61
61
61
61
62
63
63
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CS 551 Version 1.0.0
Contents
11. Ditch profile survey
Survey requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data round-tripping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Method of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interruption of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Abandonment of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality control requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surveyor competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey method quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Photographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CAD drawing files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
65
65
65
65
65
65
66
66
66
66
66
67
67
67
67
67
12. Soil characterisation sampling and testing
Sampling and testing requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of sampling and testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pre-sitework study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality control requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Field sampling competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Laboratory competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Characterisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
68
68
68
70
70
71
72
72
72
73
73
73
73
13. All assets defect survey
Survey requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data round-tripping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Desk study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Method of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interruption of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Abandonment of survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality control requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surveyor competency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey method quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Survey data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Video recordings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Photographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CAD drawing files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
75
75
75
75
75
75
75
76
76
76
76
76
76
76
76
77
77
77
77
14. Normative references
78
15. Informative references
79
4
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CS 551 Version 1.0.0
Contents
Appendix A. Drainage condition grade quick assessment
A1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A2 Structural and service condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A3 Asset grouping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A4 Excluded assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5 Condition grade quick assessment definitions and examples . . . . . . . . . . . . . . . . . . . . . . . .
A5.1 Chambers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5.2 Gullies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5.3 Inlets and outlets (with formal structure) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5.4 Inlets and outlets (without formal structure) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5.5 Pipes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5.6 Filter drains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5.7 Ditches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5.8 Enclosed channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5.9 Open channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5.10 Grassed channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5.11 Ponds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A5.12 Ancillaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
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80
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82
85
87
90
93
96
99
102
104
107
109
112
CS 551 Version 1.0.0
Release notes
Latest release notes
Document
code
CS 551
Version
number
1.0.0
Date of publication
of relevant change
October 2021
Changes made to
Date of publication
of relevant change
June 2019
Changes made to
Type of change
Change to policy, major
revision, new document
development
Major update includes five new survey or testing methods (pipework inclination, chamber scanning, ditch
profiling, soil characterisation testing, all assets survey) to reflect changing business requirements. Minor
updates to existing survey methods. Removal of schedule of requirements appendix. Minor updates to general
requirements to reflect changing business requirements. Minor clarifications of wording. Update of external
reference documents where appropriate.
Core document,
England NAA
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Previous versions
Document
code
CS 551
Version
number
0
6
Type of change
CS 551 Version 1.0.0
Foreword
Foreword
Publishing information
This document is published by National Highways.
This document supersedes SD 15/03 of the Manual of Contract Documents for Highway Works, which
is withdrawn.
Contractual and legal considerations
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This document forms part of the works specification. It does not purport to include all the necessary
provisions of a contract. Users are responsible for applying all appropriate documents applicable to
their contract.
7
CS 551 Version 1.0.0
Introduction
Introduction
Background
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This document provides the requirements for the specialist activity of surveying highway drainage
systems by a number of different methods. The selection of the most appropriate survey method is
detailed in CD 535 [Ref 5.N].
SD 15/03, and accompanying parts, set out a specification, notes for guidance and a method of
measurement, for surveying drainage pipework using closed-circuit television (CCTV). Since its
publication in 2003 the Overseeing Organisations have developed national drainage data management
systems. In order to expedite the population of these systems with drainage asset inventory and
condition information, new survey methods have been researched and developed that are both quicker
and lower cost than CCTV survey, and cover more drainage asset types than just pipework. Some of
these drainage survey methods were introduced in IAN 147/12 with supporting guidance notes
providing further detail on their application. HD 217/17 introduced the use of ground penetrating radar
(GPR) for surveying the condition of combined surface and sub-surface filter drains. The requirements
for these various drainage survey methods are now brought together and updated in this one
document, superseding the previous publications.
Assumptions made in the preparation of this document
The general requirements in GG 101 [Ref 12.N] apply to this document.
Mutual recognition
Where there is a requirement in this document for compliance with any part of a "British Standard" or
other technical specification, that requirement may be met by compliance with the Mutual Recognition
clause in GG 101 [Ref 12.N].
8
CS 551 Version 1.0.0
Abbreviations
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Abbreviations
Abbreviation
Definition
ASTM
American Society for Testing and Materials
CAT
Cable avoidance tool
CCTV
Closed-circuit television
CSA
Cross-sectional area
CSV
Comma separated value file format
DDMS
Drainage data management system
EFAW
Emergency first aid at work
FAW
First aid at work
GIS
Geographic information system
GNSS
Global navigation satellite system
GPR
Ground penetrating radar
GPS
Global positioning system
LiDAR
Light detection and ranging
RAMS
Risk assessment and method statement
SMI
Site manager's instruction
SMSTS
Site management safety training scheme
SSSTS
Site supervision safety training scheme
TQ
Technical query
WRC
Water Research Centre
9
CS 551 Version 1.0.0
Terms and definitions
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Terms and definitions
Term
Definition
All assets condition and connectivity survey
A survey carried out to determine the inventory,
asset level condition and connectivity of all
drainage assets in a drainage system.
NOTE: Also known as connectivity survey.
All assets defect survey
A survey carried out to determine the inventory,
condition and detailed defects of pipework and the
associated chambers and gullies and the
inventory, asset level condition and connectivity of
all other drainage assets in a drainage system.
Axis of drain
A longitudinal line projected centrally along the
inside of the drain (pipework or culvert).
Blockage
An obstruction within the drainage system.
Chamber
Access point that can be a manhole, catchpit or
other structure as defined in CD 535 [Ref 5.N].
Chambers defect and geometric survey by
laser scanner
A survey carried out to determine the inventory,
condition, detailed defects and internal geometry
of chambers, including the use of a laser scanner
with inbuilt panoramic still camera(s) and a
closed-circuit television (CCTV) camera.
Confined space
Any place, including a chamber, trench, pipework,
culvert or similar space where, by reason of its
nature, there is a foreseeable risk of asphyxiation,
loss of consciousness due to increased body heat,
drowning, or serious injury from fire or explosion.
Continuous defect
A longitudinal pipework defect.
Data round-tripping
The process carried out in an area of existing data
that ensures one-version-of-the-truth of the
drainage inventory and condition data is
maintained on the DDMS, by downloading the
available data before a survey commences, and
then checking, updating or adding to it in the field,
before uploading it back to the DDMS, including
any unchanged data, replacing the previous
version of the data on the DDMS.
Ditch profile survey
A survey carried out to determine the longitudinal
and cross-sectional profile of ditches in association
with an all assets condition and connectivity
survey and including the determination of potential
soil contamination.
Drainage asset
An individual component within a drainage system,
such as a gully, pipe, ditch or pond.
Drainage data management system
Overseeing Organisation's primary database for
managing information concerning drainage assets
and flooding.
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CS 551 Version 1.0.0
Terms and definitions
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(continued)
Term
Definition
Drainage highway catchment
A group of all the drainage systems and the
adjacent land they drain, between two
geographical high points of the highway network.
NOTE 1: Both carriageways of a dual carriageway
are considered part of the same catchment, but
risks can be assessed separately for each
carriageway.
NOTE 2: A drainage highway catchment can
include one or more drainage systems.
Drainage system
A group of drainage assets that are directly or
indirectly connected to each other, within a single
drainage highway catchment.
NOTE: Each individual drainage asset is part of
only one drainage system.
Filter drain condition survey by ground
penetrating radar
A survey carried out of the service condition due to
sediment contamination of the filter medium of
combined surface and sub-surface drains, and
other forms of filter drain, including the use of
ground penetrating radar (GPR).
Forced ventilation
The procedure of venting the drainage system by
removing a number of chamber covers and using
ducting, air jets and fans to force air into the
system to purge potentially dangerous gases that
have accumulated within the system.
Node
Manhole, catchpit, inspection chamber, outlet,
gully, rodding eye or any other point from which
the drainage survey commences or terminates.
Pan and tilt camera
A self-propelled camera with a directionally
adjustable lens.
Pipework and chambers defect survey by
closed-circuit television
A survey carried out to determine the inventory,
condition and detailed defects of pipework and the
associated chambers and gullies, including the
use of a closed-circuit television (CCTV) camera.
NOTE: Also known as CCTV survey.
Pipework geometric survey by laser profiler
A survey carried out to determine the pipework
internal circumferential geometry, including the use
of a laser profiler in association with a pipework
and chambers defect survey by CCTV.
Pipework inclination survey
A survey carried out to determine pipework
inclination in association with a pipework and
chambers defect survey by CCTV.
Pre-cleansing
The removal of silt and debris prior to the
commencement of the drainage survey.
Priority asset
An outfall or soakaway that presents a risk of
pollution, or a culvert that presents a risk of
flooding.
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CS 551 Version 1.0.0
Terms and definitions
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(continued)
Term
Definition
Priority asset survey
A survey carried out in areas where the highway
drainage system is unknown or uncertain, in order
to locate the outfall or soakaway point of each
drainage catchment, and any culverts passing
under the carriageway, to facilitate management of
pollution and flooding risk.
Remote survey
The survey of drainage systems by means that
preclude man-entry into the drainage assets.
Rodding camera
A CCTV camera that is moved along the pipework
using flexible rods.
NOTE: Such cameras are generally used to
access 150mm or smaller diameter pipes,
particularly those with bends.
Service condition
The performance of an asset and severity of the
defects that affect its serviceability, independent of
its structural condition.
NOTE: Service defects are addressed by
maintenance of the asset such as cleansing or
vegetation clearance.
Set-up
The process of setting up the equipment at one
chamber or other node type, for survey of the
chamber and connected pipes in one or more
directions.
Site
The location or locations of the survey or surveys
that constitute the works.
Soil characterisation sampling and testing
In situ soil sampling and laboratory testing carried
out in association with a drainage survey to
determine whether the spoil arising from potential
drainage works should be characterised as
hazardous or non-hazardous for the purposes of
off-site disposal.
Structural condition
The condition of the fabric of the asset and the
severity of defects that affect its integrity.
NOTE: Structural defects are addressed by
repairing or replacing the asset.
Task order
The instruction to the survey contractor on what
works are to be carried out for a specific drainage
survey, cross-referenced to the detailed
requirements in this standard.
Validation survey
A survey carried out to verify whether the inventory
information held on the DDMS, previously derived
from drawings, is a true record of the visible
surface point assets or not.
12
CS 551 Version 1.0.0
1.
1. Scope
Scope
Aspects covered
1.1
Highway drainage surveys shall be undertaken in accordance with the requirements stated in this
document.
NOTE
This document covers general requirements, survey equipment and procedures, quality control and
reporting requirements for validation survey, priority asset survey, filter drain condition survey by GPR,
all assets condition and connectivity survey, pipework and chambers defect survey by CCTV, pipework
geometric survey by laser profiler, pipework inclination survey, chambers defect and geometric survey
by laser scanner, ditch profile survey, soil characterisation sampling and testing, and all assets defect
survey.
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Implementation
1.2
This document shall be implemented forthwith on all schemes involving the survey of highway drainage
assets on the Overseeing Organisations' motorway and all-purpose trunk roads according to the
implementation requirements of GG 101 [Ref 12.N].
Use of GG 101
1.3
The requirements contained in GG 101 [Ref 12.N] shall be followed in respect of activities covered by
this document.
Health and safety
1.4
A pre-survey risk assessment and health and safety plan shall be prepared in accordance with HSE
L153 [Ref 14.N] making reference to any known hazards associated with the drainage system identified
in the pre-construction information and/or observed during a pre-survey daytime site visit and adopting
the safety risk assessment process of GG 104 [Ref 19.N].
1.5
The pre-construction information shall be referenced in the task order.
1.5.1
The pre-survey risk assessment and health and safety plan should be presented in a site specific Risk
Assessment and Method Statement (RAMS).
1.6
The pre-survey daytime site visit shall be carried out by the appointed scheme supervisor(s) and not be
undertaken as lone-working.
1.7
The pre-survey daytime site visit shall include identification of site hazards and constraints such as
overhead cables, steep slopes, dense vegetation, nearby livestock etc.
1.8
Any chamber, pipework or culvert forming part of a highway drainage system must be classified as a
confined space in respect of personnel entry in accordance with SI 1997/1713 [Ref 11.N].
NOTE
A confined space is defined in SI 1997/1713 [Ref 11.N] as any place in which by virtue of its enclosed
nature there arises a foreseeable risk such as asphyxiation from gas, lack of oxygen or a build-up of
fumes due to the operations being undertaken, loss of consciousness due to increased body heat,
drowning, or serious injury from fire or explosion due to an explosive atmosphere.
1.9
Person entry to the drainage system shall be avoided where remote access survey methods can be
employed.
NOTE
The Confined Spaces Regulations SI 1997/1713 [Ref 11.N] require that no person enters a confined
space to carry out work for any purpose unless it is not reasonably practicable to achieve that purpose
without such entry.
1.10
All electrical equipment to be used in potentially explosive atmospheres must be in accordance with SI
2016/1107 [Ref 22.N].
1.11
All highway drainage systems shall be classified as either zone 1 or zone 2 for the use of electrical
equipment in potentially explosive atmospheres, in accordance with SI 2002/2776 [Ref 1.I].
13
CS 551 Version 1.0.0
1. Scope
1.12
The site zone classification for the use of electrical equipment in potentially explosive atmospheres
applicable to the specific site shall be stated in the task order.
1.13
Gas detectors shall be used in all confined spaces.
1.13.1
Gas detectors should be pumped and capable of detecting oxygen deficiency, explosive atmosphere,
hydrogen sulphide, carbon monoxide and ammonia.
1.14
The drainage survey team shall be able to maintain immediate 2-way contact with the Overseeing
Organisation's representative for the duration of the survey.
1.15
The following site survey supervision shall be provided by person(s) undertaking no other roles on site:
1) supervisor(s) trained under the site supervision safety training scheme (SSSTS);
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2) where the supplier is the Principal Contractor in accordance with The Construction (Design &
Management) Regulations SI 2015 No.51 (CDM Regs) 2015 [Ref 10.N] supervisor(s) trained under
the site management safety training scheme (SMSTS) or equivalent;
3) a minimum of one supervisor per two survey crews working no further than 4km apart;
4) a minimum of one supervisor to cover the survey works within each traffic management layout.
1.16
The following first aid provision shall be made:
1) for each survey site a certified first aider trained to HSE Level 3 first aid at work (FAW);
2) for each site crew a certified first aider trained to HSE Level 3 emergency first aid at work (EFAW);
3) within in each site vehicle a fully equipped, in date, BS 8599-2 [Ref 8.N] compliant first aid kit the
contents of which have been based on a needs assessment.
NOTE
FAW training is run over a minimum of three days and EFAW training is run over a minimum of one day.
1.17
On-site welfare facilities must be provided for the use of the site team and the Overseeing
Organisation's representative that is compliant with SI 1996/1592 [Ref 21.N].
1.18
Where an access chamber cover or gully grating or other asset is damaged during the drainage survey,
or found to have been previously damaged or broken, the survey team shall:
1) provide temporary protection to the asset;
2) notify the Overseeing Organisation's representative immediately;
3) remain on site until the Overseeing Organisation's representative is in attendance;
4) ensure that the traffic management is not removed.
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CS 551 Version 1.0.0
2.
2. General requirements
General requirements
Scope of works
2.1
The drainage survey shall be carried out as detailed in this document.
2.2
Where this document provides alternative options within particular requirements the task order shall
state which option is to be carried out for the specific survey.
2.3
The drainage survey method shall be one or more of the following as defined in this document:
1) validation survey;
2) priority asset survey;
3) filter drain condition survey by GPR;
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4) all assets condition and connectivity survey;
5) pipework and chambers defect survey by CCTV;
6) pipework geometric survey by laser profiler;
7) pipework inclination survey;
8) chambers defect and geometric survey by laser scanner;
9) ditch profile survey;
10) soil characterisation sampling and testing; or,
11) all assets defect survey.
2.4
The location of the drainage survey shall be as detailed in the task order.
2.5
Any constraints on the drainage survey shall be detailed in the task order.
2.5.1
Constraints listed in the task order should include the following:
1) restrictions on access routes to the whole site, or sections of the site;
2) restrictions on the days or hours of working;
3) restrictions on the overall programme or sequencing of the works;
4) restrictions imposed by traffic management arrangements;
5) restrictions due to other works within the area; or,
6) restrictions due to environmental or ecological constraints.
2.6
The drainage survey shall be measured in accordance with the process stated by the Overseeing
Organisation and any specific method of measurement provided for the works.
2.7
A shift report shall be submitted to the Overseeing Organisation's representative no later than two
hours into the following shift.
2.7.1
The shift report should be clear, concise and detail progress, issues, delays, breakdowns and decisions
agreed with the Overseeing Organisation's representative.
2.8
Off-road survey vehicles shall be provided where necessary to complete the survey.
2.9
Vegetation clearance shall be provided where necessary to complete the survey.
2.10
Evidence of the competency of the site vegetation clearance personnel shall be provided prior to
sitework.
2.11
The means of transferring the survey data deliverable shall be either:
1) by internet transfer and non-returnable portable storage device; or
2) by internet transfer only; or
3) by non-returnable portable storage device only; or
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4) by DVD.
2.12
The responsibility for traffic management shall be as detailed in the task order.
2.13
Traffic management shall be carried out and supervised in accordance with the MCHW Series 0100
[Ref 16.N].
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3.
3. Validation survey
Validation survey
Survey requirements
Scope of survey
3.1
A validation survey shall be carried out to verify whether the inventory information held on the drainage
data management system (DDMS), previously derived from drawings, is a true record of the visible
surface point assets or not.
3.2
A validation survey shall include the following:
1) a walkover survey to verify surface visible point assets only;
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2) determination of whether the recorded location and asset type of the surface visible point assets is
correct or not; and,
3) submission of digital data in the format defined by the Overseeing Organisations in the NAAs to CD
535 [Ref 5.N]
NOTE 1
A validation survey is:
1) a quick walkover survey;
2) used to assess drainage data that has been derived from drawings, not previous field surveys;
3) carried out in the daytime;
4) only carried out where it is safe to access the verge, hard shoulder or footpath without lane closures,
unless sharing other traffic management arrangements.
NOTE 2
A validated survey does not:
1) primarily record previously unrecorded inventory, although any such point assets found during the
course of the survey are to be captured;
2) record asset condition;
3) require any prior vegetation clearance.
Survey data round-tripping
3.3
The drainage inventory information on the DDMS in the catchment(s) to be surveyed shall be
round-tripped in accordance with the specific procedures and formats detailed by the Overseeing
Organisations in the NAAs to CD 535 [Ref 5.N] by:
1) downloading the available information;
2) updating the inventory status of the surface visible point assets in the field;
3) retaining as part of the data, without change, any inventory and condition information on any
non-surveyed assets; and,
4) submission for uploading of this information to the DDMS.
NOTE
Additional activities required to complete the round-tripping of drainage information to the DDMS are
provided in the NAAs to CD 535 [Ref 5.N].
Survey equipment
3.4
The validation survey shall be recorded on a hand-held computer equipped with:
1) a mobile geographic information system (GIS);
2) an in-built or connected global positioning system (GPS) receiver capable of recording locational
position to the accuracy stated in CD 535 [Ref 5.N] for an inventory survey; and,
3) the ability to take digital photographs or to link to photographs taken by a digital camera.
3.4.1
The mobile GIS should be pre-loaded with the following data sets prior to the survey (where available):
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1) the downloaded DDMS drainage system data;
2) detailed topographic mapping for the site;
3) high resolution aerial photography for the site; and,
4) marker post locations for the site.
Method of survey
3.5
The location of each surface visible point asset in the DDMS data shall be identified in the field using a
combination of the GPS, the detailed mapping, the marker posts and/or the aerial photography.
3.6
The inventory status of each surface visible "unvalidated" point asset in the DDMS data shall be
changed to one of the following:
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1) "confirmed" where the location of the asset is correct to within ±5m tolerance, and the asset type is
correct;
2) "modified" where the location of the asset is correct to within ±5m tolerance, but the asset type is
incorrect; or,
3) "unproven" where there is no corresponding point asset within ±5m of the location shown on the
map.
3.6.1
Chambers should be "confirmed" without lifting the covers to determine the chamber type.
3.6.2
Where the status is "modified" the asset type should be determined in accordance with CD 535 [Ref
5.N].
3.6.3
Point assets in the carriageway or central reserve should be checked remotely from the side of the road
or from the nearest overbridge, their location "eyed-in" against the aerial photography and marked as
"confirmed" where it is judged to be correct.
3.6.4
Any point assets that can not be checked because the location is not accessible, is hidden, or is
otherwise not included in the survey should retain their default status of "unvalidated".
3.6.5
Although the validation survey concentrates on the surface visible point assets, the surface visible
continuous assets should also be observed, as an understanding of the system connectivity will greatly
aid the identification and checking of the point assets.
3.7
Digital photographs shall be taken of any safety related defects that are identified in the survey.
3.8
Where a point asset is encountered during the validation survey that is not in the DDMS data (to within
a tolerance of ±5m) it shall be added as a "new" asset, recording the following details:
1) the location of the asset to the accuracy stated in CD 535 [Ref 5.N] for inventory survey and to the
national survey grid stated by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N];
2) the asset type in accordance with CD 535 [Ref 5.N]; and,
3) any relevant remarks.
3.8.1
Where a chamber is found that is not in the DDMS data, that is part of the drainage system being
surveyed, it should be recorded as a manhole, unless there is reasonable evidence to indicate
otherwise.
3.8.2
When "new" point assets are added there should be no attempt to join them with any other assets, new
or existing.
3.8.3
Where a point asset is found to be more than 5m from its recorded location, this should be recorded as
follows:
1) the original asset in the DDMS data is changed to "unproven"; and,
2) the asset as found in the field is recorded as "new" at the new location.
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Termination of survey
3.9
The validation survey shall be terminated when either:
1) all of the accessible surface visible point assets in the DDMS data have been checked; or,
2) the first 20% of the surface visible point assets in the DDMS data have been checked and all found
to be "confirmed" and spot checking of a further 20% are also all found to be "confirmed"; or,
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3) the first 20% of the surface visible point assets in the DDMS data have been checked and all found
to be "unproven" and spot checking of a further 20% are also all found to be "unproven".
NOTE
It is not necessary to survey all of the surface visible point assets in the DDMS data where they are
either all "confirmed" or all "unproven".
3.9.1
Where the status of the surveyed surface visible point assets in the DDMS data is mixed, all of the
accessible assets should be surveyed.
Quality control requirements
Surveyor competency
3.10
The senior surveyor shall have at least five years experience of surveying highway drainage systems.
Survey method quality control
3.11
At the start of each survey the alignment between the GIS mapping, aerial photography and GPS
location shall be checked to be within +/-5m at a clearly identifiable feature on the mapping and aerial
photography.
3.11.1
Where the data sets do not align to within acceptable tolerance, further checks should be carried out to
determine the source of the problem and the matter rectified before proceeding with the survey.
3.12
The validation survey procedure shall maintain the DDMS data file format in accordance with the
requirements of the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N], during updating in the
GIS.
Reporting requirements
Data submission
3.13
The survey report shall consist of a submission for upload to the DDMS of the following digital data:
1) the round-tripped DDMS survey data, including any original unchanged data, as well as new and
changed data, as separate files for each catchment; and,
2) any digital photographs taken during the survey referenced to the asset data in accordance with the
requirements of the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
Survey data
3.14
All survey data shall be reported using the standard coding system and nomenclature defined by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
3.15
All recorded survey data shall be submitted for upload to the DDMS in the standard digital format(s)
defined by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
3.16
All round-tripped existing drainage data from the DDMS shall retain the unique reference of each asset.
3.17
Where "new" assets are added to the data during the survey they shall be assigned a field reference
that is unique within the survey.
NOTE
A permanent unique asset reference is automatically assigned by the DDMS when the data is
uploaded.
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Photographs
3.18
All photographs shall be:
1) in colour;
2) in JPEG format as .JPG files;
3) submitted for upload to the DDMS as documents attached to the asset to which they relate; and,
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4) at a resolution of at least 1.0 megapixels.
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4.
4. Priority asset survey
Priority asset survey
Survey requirements
Scope of survey
4.1
A priority asset survey shall be carried out in areas where the highway drainage system is unknown or
uncertain, in order to locate the outfall or soakaway point of each drainage catchment, and any culverts
passing under the carriageway, to facilitate management of pollution and flooding risk.
4.2
A priority asset survey shall include the following:
1) a desk study to identify potential priority asset locations for field study;
2) a walkover survey of the targeted locations;
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3) recording of the location, inventory and asset level condition of each identified priority asset; and,
4) submission of digital data in the format defined by the Overseeing Organisations in the NAAs to CD
535 [Ref 5.N].
NOTE 1
A priority asset survey is:
1) carried out where there is little or no drainage inventory on the DDMS;
2) a "quick win" to expedite the acquisition of knowledge of the key drainage assets that can present a
risk of either pollution (outfalls and soakaways) or flooding (culverts);
3) a combination of a desk study and a walkover survey;
4) carried out in the daytime; and,
5) carried out only where it is safe to access the verge, footpath, adjacent earthworks or adjacent land
without lane closures, unless sharing other traffic management arrangements.
NOTE 2
A priority asset survey does not:
1) record the drainage assets that the priority assets connect to; nor,
2) require any prior vegetation clearance.
Survey data round-tripping
4.3
Survey data shall be round-tripped from the DDMS where available.
4.4
Where there is some drainage inventory information in the catchment(s) to be surveyed on the DDMS,
the survey shall round-trip this data in accordance with the specific procedures and formats detailed by
the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] by:
1) downloading the available information;
2) confirming or updating the inventory and condition of the priority assets in the field;
3) retaining as part of the data, without change, any inventory and condition information on any
non-surveyed assets; and,
4) submission for uploading of this information to the DDMS.
4.5
Where there is no existing drainage inventory information in the catchment(s) to be surveyed on the
DDMS, the survey shall consist of the following:
1) a first time survey of the inventory and condition of the priority drainage assets only; and,
2) the submission for upload of this information to the DDMS in accordance with specific procedures
and formats detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
NOTE
Additional activities required to complete the round-tripping of drainage information to the DDMS are
provided in the NAAs to CD 535 [Ref 5.N].
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Desk study
4.6
Available data sets relevant to the identification of potential priority drainage asset locations shall be
collated.
NOTE
The following data sets can be used where available for identifying potential priority drainage asset
locations:
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1) existing drainage asset information including:
a) any existing drainage data on the DDMS;
b) any drainage, pavement, earthworks or general layout as-built drawings that show drainage
assets;
c) any locally available drainage asset survey data;
d) any drainage asset maintenance data;
e) any environmental or soft estate data that records drainage assets; and,
f) any structures data that records culverts;
2) existing topographic data that can help to identify the fall of the land, low points in the highway
network and water courses, including:
a) national survey detailed topographic mapping;
b) detailed aerial photography;
c) high resolution light detection and ranging (LiDAR) survey data;
d) high resolution digital terrain models;
e) data on the highway gradient and falls;
f) any locally available survey data;
g) any modelling carried out to identify highway drainage catchments; and,
h) national detailed river network mapping;
3) other existing relevant data that can assist the desk study including:
a) local knowledge of inspectors, engineers and maintenance staff who have worked on the
network for a long time;
b) the record of historic flood events;
c) the record of flooding hotspots;
d) national flood hazard mapping;
e) mapping of the highway land ownership boundary; and,
f) previous local studies that can contain a drainage element on topics such as: flood mitigation,
pollution control measures, environmental impact.
4.7
A desk study shall be carried out by compiling the various relevant data sets into a GIS to identify
potential priority drainage asset locations for investigation in the field.
NOTE
The following steps can be undertaken to help identify potential priority drainage asset locations and
prepare for the field survey:
1) locate all known priority drainage assets in the GIS, identify the source(s) of each data point, and
hence the confidence in their location;
2) use any available drainage and topographic information to identify drainage catchments and likely
flow directions, and hence target the general area of potential priority drainage assets;
3) use the topographic data, aerial photography, flooding data and culvert information to identify low
points in the road network, and the surrounding ground, with adjacent or crossing water courses,
and mark these areas as targets for field inspection;
4) inspect the aerial photography for small ponds adjacent to the carriageway which can be soakaway
infiltration basins;
5) where high resolution aerial photography is available, inspect this in association with the identified
low points in the road network and water courses to see whether outfall or culvert structures can be
identified;
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6) review the resultant map of known priority drainage assets and target locations, and identify gaps
where possible drainage catchments are missing priority drainage assets or target locations;
7) refer back to the aerial photography, maps and topographic data, and identify additional targets for
field inspection in the areas of the gaps;
8) identify from the topographic mapping and aerial photography appropriate access routes to the
areas requiring field inspection;
9) consult the available land ownership information to determine whether the field survey is likely to
require access to third party land, and seek permissions where required; and,
10) prepare a field inspection programme.
Survey equipment
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4.8
The priority asset shall be recorded on a handheld computer equipped with:
1) a mobile GIS;
2) an in-built or connected GPS receiver capable of recording locational position to the accuracy stated
in CD 535 [Ref 5.N] for inventory survey; and,
3) the ability to take digital photographs or to link to photographs taken by a digital camera.
4.8.1
The mobile GIS should be pre-loaded with the following data sets prior to the priority asset survey
(where available):
1) the downloaded DDMS drainage system data (if any);
2) the desk study GIS mapping, aerial photography and other data sets; and,
3) the known priority drainage assets, the target locations and the identified access routes.
4.8.2
The following equipment may be useful for the field survey:
1) a metal detector for finding buried soakaway chamber covers;
2) an appropriate means for opening and lifting chamber covers for identifying soakaways or for
determining flow direction to outfalls, depending on the local health and safety requirements.
Method of survey
4.9
At each inspection area the priority drainage asset shall be located or confirmed as absent with the
validation status being recorded as either:
1) "confirmed" where the location of the asset downloaded from the DDMS is correct to within ±5m
tolerance and the inventory details are all correct; or,
2) "modified" where the location and/or the inventory details downloaded from the DDMS have been
updated; or,
3) "new" where a previously unrecorded asset has been found; or,
4) "unvalidated" where a priority asset is suspected but not positively proven and requires further
investigation such as:
a) a chamber has been found but the cover could not be lifted to confirm that it is a soakaway; or
b) an outfall to a sewer is suspected.
4.9.1
Where no asset was found at the location downloaded from the DDMS, the asset should be deleted.
4.10
All mandatory data fields for asset inventory and survey parameters shall be recorded using the
procedures detailed in CD 535 [Ref 5.N] and the codes and formats detailed by the Overseeing
Organisations in the NAAs to CD 535 [Ref 5.N].
4.11
Where optional data fields for asset inventory and survey parameters are recorded, the codes and
formats detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] shall be used.
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4.11.1
Soakaway chamber inspections may include the lifting of manhole covers to confirm the type of
soakaway structure where local health and safety procedures permit.
4.11.2
There should be no internal investigation of soakaway chambers, culverts or other confined spaces.
4.12
The overall asset level service and structural condition of the priority asset shall be assessed in
accordance with the drainage condition grade quick assessment procedure given in Appendix A, so far
as this is possible given any health and safety constraints.
4.13
Any significant defects in either the service or structural condition shall be recorded and photographed,
although full defect recording is not required.
4.14
Digital photographs shall be taken of every priority drainage asset to illustrate the type, location and
condition of each asset.
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Quality control requirements
Surveyor competency
4.15
The senior surveyor shall have at least five years experience of surveying highway drainage systems.
Survey method quality control
4.16
The priority asset survey results shall be reviewed in the field at least daily to identify any gaps.
NOTE
Where gaps are apparent in the priority asset survey results, the following can be assessed:
1) where no outfall structure has been found, could the outfall be at the ownership boundary and
without a structure?;
2) is the flow passing under the carriageway so small that it can be carried by a small diameter pipe
rather than a culvert?;
3) is the structure carrying the flow under the carriageway more correctly recorded as a bridge rather
than a culvert?;
4) could the outfall or soakaway be further away from the highway?;
5) could the outfall or soakaway be on the other side of the road?;
6) could the outfall be on the other side of the water course?;
7) could there be a buried soakaway chamber cover that can be identified by a metal detector?;
8) is a manhole actually a soakaway chamber that can be confirmed by lifting the cover?;
9) could there be a buried infiltration trench?;
10) could a nearby pond actually be an infiltration basin?;
11) could the drainage discharge to a foul sewer?; and,
12) has there been confusion in the nomenclature of outfall, outlet and inlet?
Reporting requirements
Data submission
4.17
The survey report shall consist of a submission for upload to the DDMS of the following digital data:
1) the round-tripped DDMS survey data (if any) combined with the new survey data as separate files
for each catchment; and,
2) any digital photographs taken during the survey referenced to the asset data in accordance with the
requirements of the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
Survey data
4.18
All survey data shall be reported using the standard coding system and nomenclature defined by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
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4.19
All recorded survey data shall be submitted for upload to the DDMS in the standard digital format(s)
defined by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
4.20
Any round-tripped existing drainage data from the DDMS shall retain the unique reference of each
asset.
4.21
"New" assets added to the data during the survey shall be assigned a field reference that is unique
within the survey.
NOTE
A permanent unique asset reference is automatically assigned by the DDMS when the data is
uploaded.
Photographs
4.22
All photographs shall be:
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1) in colour;
2) in JPEG format as .JPG files;
3) submitted for upload to the DDMS as documents attached to the asset to which they relate;
4) at a resolution of at least 1.0 megapixels.
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5.
5. Filter drain condition survey by GPR
Filter drain condition survey by GPR
Survey requirements
Scope of survey
5.1
A filter drain condition survey shall be carried out to determine the service condition due to sediment
contamination of the filter medium of combined surface and sub-surface drains, and other forms of filter
drain, including the use of ground penetrating radar (GPR).
5.2
A filter drain condition survey by GPR shall include the following:
1) details of the location, date, equipment and personnel of the survey;
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2) GPR survey of the required filter drains;
3) survey of the location and type of all associated nodes at each end of each filter drain to the
accuracy stated in CD 535 [Ref 5.N] for a condition survey, and to the national survey grid stated by
the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N];
4) interpretation and recording of the variation in void ratio of the filter medium along the length of the
filter drain as an indication of the degree to which the filter medium has become contaminated with
sediment;
5) recording of the overall asset level service and structural condition grades of the filter medium;
6) preparation of a report on recommended remedial works or further investigations; and,
7) submission of a digital report and digital data sets in the formats defined by the Overseeing
Organisations in the NAAs to CD 535 [Ref 5.N].
NOTE
A filter drain condition survey by GPR is;
1) a field survey along the surface centre line of a filter drain;
2) carried out using a vehicle-mounted GPR; and,
3) carried out either remote from the carriageway or at the edge of the carriageway and could require
traffic management.
Survey data round-tripping
5.3
Survey data shall be round-tripped from the DDMS where available.
5.4
Where there is some drainage inventory information in the catchment(s) to be surveyed on the DDMS,
the survey shall round-trip this data in accordance with specific procedures and formats detailed by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] by:
1) downloading the available information;
2) confirming or updating the inventory, condition and defects of the filter drain medium and the
inventory of the associated nodes in the field;
3) retaining as part of the data, without change, any inventory and condition information on any
non-surveyed assets; and,
4) submission for uploading of this information to the DDMS.
5.5
Where there is no drainage inventory information in the catchment(s) to be surveyed on the DDMS the
survey shall consist of:
1) a first time survey of the inventory, condition and defects of the filter drain medium and the inventory
of the associated nodes; and,
2) the submission for upload of this information to the DDMS in accordance with specific procedures
and formats detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
NOTE
Additional activities required to complete the round-tripping of drainage information to the DDMS are
provided in the NAAs to CD 535 [Ref 5.N].
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Survey equipment
5.6
The filter drain condition survey equipment shall be checked prior to each shift in accordance with the
quality control procedures detailed in Section 5, to ensure that it is maintained in full working order.
5.7
The radar penetration shall be effective to a depth of at least 750 mm.
5.8
The location of the radar antenna shall be continuously recorded by GPS capable of recording
locational position to the accuracy stated in CD 535 [Ref 5.N] for condition survey, either mounted
above the centre of the antenna, or in such a way that the location of the centre of the antenna can be
determined.
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Method of survey
5.9
An inspection of the site shall be carried out in advance of the filter drain condition survey to determine
where there are any barriers or other obstructions that would make a vehicle-mounted GPR survey
impractical.
5.10
The radar survey shall be carried out progressing at a speed to optimise the recorded data in
accordance with the equipment calibration.
5.11
The radar antenna shall be positioned at a constant height relative to the surface of the filter drain.
NOTE
Undulations in the surface of the filter drain can make it impractical for the antenna to ride along the top
of the drain.
5.11.1
Filter drains located at the edge of the carriageway may be surveyed by an antenna mounted to the
side of a vehicle such that the antenna is positioned at a constant height relative to the carriageway and
can be accurately positioned and transported along the line of the filter drain.
5.11.2
Filter drains located remote from the carriageway may be surveyed by an antenna mounted to the front
or rear of an all-terrain vehicle that can straddle the filter drain.
5.12
The filter drain condition survey shall measure and report the service condition of the filter medium
along the centre line.
NOTE
Results from other survey paths can be affected by fines clogging the filter medium at the edge of the
drain.
5.13
The radar gain shall be set to optimise the recorded data in accordance with the equipment calibration.
5.14
The location and type of all associated nodes shall be surveyed at each end of each filter drain to the
accuracy stated in CD 535 [Ref 5.N] for a condition survey and to the national survey grid stated by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
5.14.1
The nodes at each end of a filter drain may be either:
1) a chamber; or,
2) a ghost node at the start of the filter drain where there is no physical point asset; or,
3) a ghost node at the junction with another filter drain where there is no physical point asset; or,
4) a phantom node where the survey is abandoned before the end of the filter drain and the
continuation of the filter drain is not visible.
Interruption of survey
5.15
Where movement off-line is necessitated by a barrier or street furniture, the antenna shall be
re-positioned over the centre of the drain once the obstacle has been passed.
5.16
Where a survey run is interrupted by an obstruction the survey shall record the following using the
codes defined by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N]:
1) the start and end positions of the gap in the survey; and,
2) the nature of the obstruction.
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Abandonment of survey
5.17
A survey run of a filter drain shall be abandoned for any of the following reasons:
1) the filter drain could not be found at all;
2) the continuation of the filter drain could not be found;
3) a continuous obstruction prevents further access; or,
4) a situation has occurred that places the survey equipment, the survey personnel, the drainage asset
or the road users at risk.
5.18
Where a filter drain condition survey run is abandoned then the following shall be carried out:
1) recording of the situation on the survey record;
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2) photograph the issue;
3) recording of the appropriate code for the unsurveyed length of filter drain in accordance with the
requirements of the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N]; and,
4) recording of the appropriate node type and location as one of the following:
a) where the filter drain could be found but not accessed a ghost node or chamber is recorded at
the end of the unsurveyed filter drain;
b) where the continuation of the filter drain could not be found a phantom node is recorded at the
end of the surveyed section; or,
c) where a filter drain could not be found at all the existing DDMS record (where there is one) is
deleted from the data.
Quality control requirements
Surveyor competency
5.19
Evidence shall be provided that the surveyor undertaking the GPR survey has received training in the
execution and interpretation of GPR surveys.
Survey method quality control
5.20
Prior to the commencement of works a quality control procedure shall be submitted detailing:
1) the procedure for ensuring consistency of product;
2) how quality of product will be monitored during the works;
3) the equipment calibration method;
4) the results of the calibration carried out immediately prior to the works;
5) certification for the radar confirming that it is not susceptible to outside interference; and,
6) the method of interpretation of the void ratio.
5.21
The equipment calibration shall be provided as a chart detailing the relationship between image colour
on the output results and filter medium void ratio.
5.21.1
The calibration chart should be similar to the example given in Figure 5.21.1.
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5. Filter drain condition survey by GPR
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Figure 5.21.1 GPR example calibration chart
Reporting requirements
Data submission
5.22
The survey report shall consist of a submission for upload to the DDMS of the following digital data:
1) a survey report in PDF format as detailed in the report requirements;
2) the round-tripped DDMS survey data (if any) combined with the new survey data as separate files
for each catchment; and,
3) any digital photographs taken during the survey.
Report
5.23
A report shall be provided in PDF format presenting the following:
1) a graphical output of the filter drain condition survey trace provided to scale as a digital image for
each length of filter drain surveyed showing the following:
a) the unique asset reference of the filter drain;
b) the unique references of the nodes at each end of the filter drain, whether they are physical
assets or not;
c) distance along the filter drain in metres from the upstream end;
d) a vertical trace of the survey results colour coded in accordance with the equipment calibration;
and,
e) vertical distance down the trace with a scale in 0.1-m increments;
2) an interpretation of each survey trace dividing the trace longitudinally into zones of interpreted void
ratio carried out in accordance with Table 5.23.1;
3) overall service and structural condition grades for each filter drain determined;
4) a summary of those sections of filter drain with an interpreted overall poor void ratio or standing
water; and,
5) recommendations for the location and nature of any remedial works or further investigations.
NOTE
Two graphical traces can be provided for each filter drain to achieve optimum results, one for the upper
level to approximately 300 mm depth and the second for the lower level to the carrier pipe, or to the
base of the filter drain where there is no carrier pipe.
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5.23.1
5. Filter drain condition survey by GPR
The condition survey and the resultant recommendations should be consistent with the examples given
in Table 5.23.1.
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GPR survey trace colour
(adopting colour
scheme of example
GPR calibration)
Interpretation
Interpreted void ratio
Predominantly green or
yellow
Filter medium with a
higher void ratio in line
with type B grading
suggesting good
performance.
Good void ratio
Predominantly orange
with isolated patches of
reds
Filter medium has a
locally reducing
permeability suggesting
adequate performance.
Service condition (void
ratio) defect codes
Service condition defect
scores
Recommendation
CS 551 Version 1.0.0
Table 5.23.1 GPR example interpretation and recommendations
No further action
required
31
Predominantly reds
Filter medium with a
lower void ratio and
probable sediment
contamination or filter
medium outside the type
B grading criteria (such
as type A or C grading)
suggesting poor
performance.
Poor void ratio
Replace or recycle the
filter medium aggregate
where in excess of 20m
length of filter drain
affected. Reassess void
ratio after remedial
works.
Predominantly blue
Indicates moisture
present. Where present
outside a period of
precipitation this can
indicate a blockage in
the carrier pipe or
standing water in the
filter drain due to an
underlying problem that
can adversely affect the
pavement construction
and/or earthwork
performance.
Standing water
Service condition (void
ratio) defect codes as
defined by the
Overseeing
Organisations in the
NAAs to CD 535 [Ref
5.N]
Service condition defect
scores as defined by the
Overseeing
Organisations in the
NAAs to CD 535 [Ref
5.N]
Further investigation
required
5. Filter drain condition survey by GPR
Adequate void ratio
Remedial works
probably not necessary
at present. Monitor
situation.
CS 551 Version 1.0.0
NOTE
5. Filter drain condition survey by GPR
The zone of worst interpreted void ratio determines the overall service condition grade for the filter
drain as follows:
1) where the whole filter drain has a good interpreted void ratio the service condition is grade 1;
2) where any part of the filter drain has an adequate interpreted void ratio, and there is no poor void
ratio and no areas of standing water, the service condition is grade 3;
3) where any part of the filter drain has a poor interpreted void ratio the service condition is grade 5; or,
4) where any part of the filter drain is interpreted as having standing water the service condition is
grade 5.
5.24
The PDF report shall be submitted for upload to the DDMS as defined by the Overseeing Organisations
in the NAAs to CD 535 [Ref 5.N].
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Survey data
5.25
All survey data shall be reported using the standard coding system and nomenclature defined by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
5.26
All coding shall be directly entered into a computer or handheld device that restricts entries to valid
codes.
5.27
Where the survey is round-tripping existing drainage data from the DDMS the unique reference of each
asset shall be retained in the round-tripped data.
5.28
Where new assets are added to the data during the survey they shall be assigned a field reference that
is unique within the survey.
NOTE
A permanent unique asset reference is automatically assigned by the DDMS when the data is
uploaded.
5.29
At the commencement of the survey of every length of filter drain between consecutive access points,
the surveyor shall complete new header information in accordance with the requirements of the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
5.30
Every filter drain shall be divided longitudinally into zones of the same interpreted void ratio in
accordance with Table 5.23.1, recording the following:
1) distance along the filter drain from the upstream end to the start and end of each discrete zone of
interpreted void ratio;
2) the interpreted service condition (void ratio) defect code for the discrete zone, in accordance with
the requirements of the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N]; and,
3) the service condition defect code for any unsurveyed lengths, in accordance with the requirements
of the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
5.30.1
Where more than one survey trace is obtained for a filter drain the void ratio zones should be interpreted
from an aggregate of all the available survey data but disregarding any unrepresentative data.
5.31
The overall asset level structural condition grade of the filter drain shall be assessed in accordance with
the drainage condition grade quick assessment procedure given in Appendix A and reported using the
structural condition defect codes in accordance with the requirements of the Overseeing Organisations
in the NAAs to CD 535 [Ref 5.N].
5.32
Each of the interpreted service condition (void ratio) defect codes and structural condition defect codes
shall be scored in accordance with the scoring system detailed by the Overseeing Organisations in the
NAAs to CD 535 [Ref 5.N].
5.32.1
Automated condition scoring should be carried out by the recording software or by the DDMS during
data upload.
5.33
The overall asset level service condition grade shall be derived by aggregating the scores for each
recorded defect code in accordance with the aggregating procedure detailed in CD 535 [Ref 5.N] for
continuous assets.
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5. Filter drain condition survey by GPR
5.33.1
Automated asset level condition grading should be carried out by the recording software or by the
DDMS during data upload.
NOTE
In most cases the adoption of this aggregating procedure results in the zone of worst interpreted void
ratio determining the overall service condition grade.
5.34
All recorded survey data shall be submitted for upload to the DDMS in the standard digital format(s)
defined by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
Photographs
5.35
All photographs shall be:
1) in colour;
2) in JPEG format as .JPG files;
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3) submitted for upload to the DDMS as documents attached to the asset to which they relate; and,
4) at a resolution of at least 1.0 megapixels.
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6.
6. All assets condition and connectivity survey
All assets condition and connectivity survey
Survey requirements
Scope of survey
6.1
An all assets condition and connectivity survey shall be carried out to determine the inventory, asset
level condition and connectivity of all drainage assets in a drainage system.
6.2
An all assets condition and connectivity survey shall include the following:
1) desk study of available drainage information and aerial photography;
2) details of the location, date, equipment and personnel of the survey;
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3) survey of all drainage assets forming the drainage system consisting of:
a) visual inspection of the surface drainage assets;
b) lifting manhole covers and gratings and inspecting the chamber and pipework using a pole
mounted camera;
c) assumptions on below ground pipework and inaccessible assets that could not be inspected;
4) identification of the asset type of all surveyed assets in accordance with the classification system
detailed in CD 535 [Ref 5.N];
5) survey of the location of all assets to the accuracy stated in CD 535 [Ref 5.N] for condition survey
and to the national survey grid stated by the Overseeing Organisations in the NAAs to CD 535 [Ref
5.N];
6) recording of all the mandatory data fields for asset inventory and survey parameters using the codes
detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] for all assets surveyed;
7) recording of the optional data fields for asset inventory and survey parameters using the codes
detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] for all assets surveyed as
far as safe access permits;
8) recording of the overall asset level structural and service condition grade for all assets surveyed
using the drainage condition grade quick assessment procedure given in Appendix A;
9) recording of the connectivity and flow direction for every continuous drainage asset using the codes
detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N];
10) recording of the level of certainty/uncertainty in the survey data using the codes detailed by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N];
11) taking of still photographs showing the typical nature of the assets surveyed; and,
12) submission of digital data in the format defined by the Overseeing Organisations in the NAAs to CD
535 [Ref 5.N].
NOTE 1
An all assets condition and connectivity survey is:
1) a combination of a desk study and a quick walkover survey;
2) carried out with internal examination of the below-ground assets at accessible chambers only;
3) carried out in the daytime; and,
4) carried out only where it is safe to access the verge, hard shoulder, footpath, adjacent earthworks or
adjacent land without lane closures, unless sharing other traffic management arrangements.
NOTE 2
An all assets condition and connectivity survey does not:
1) capture detailed defect level condition of the assets, although where safety critical defects are found
these are recorded; nor,
2) require any prior vegetation clearance.
Survey data round-tripping
6.3
Survey data shall be round-tripped from the DDMS where available.
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6.4
6. All assets condition and connectivity survey
Where there is some drainage inventory information in the catchment(s) to be surveyed on the DDMS
the survey shall round-trip this data in accordance with specific procedures and formats detailed by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] by:
1) downloading the available information;
2) confirming or updating the inventory, condition and connectivity of all the drainage assets that
constitute the drainage system;
3) retaining as part of the data, without change, any inventory and condition information on any
non-surveyed assets; and,
4) the submission for uploading of this information to the DDMS.
6.5
Where there is no drainage inventory information in the catchment(s) to be surveyed on the DDMS the
survey shall consist of the following:
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1) a first time survey of the inventory, condition and connectivity of all the drainage assets that
constitute the drainage system; and,
2) the submission for upload of this information to the DDMS in accordance with specific procedures
and formats detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
NOTE
Additional activities required to complete the round-tripping of drainage information to the DDMS are
provided in the NAAs to CD 535 [Ref 5.N].
Desk study
6.6
Available data sets relevant to identification of drainage assets shall be collated.
NOTE
The data sets listed for priority asset surveys, where available, can be used for identifying drainage
asset locations.
6.7
A desk study shall be carried out by compiling the various relevant data sets into a GIS to identify
drainage asset locations for investigation in the field.
NOTE
The steps listed for priority asset surveys can be used to help identify drainage asset locations and
prepare for the field survey.
Survey equipment
6.8
The all-assets condition and connectivity survey shall be recorded on a handheld computer equipped
with:
1) a mobile GIS;
2) an in-built or connected GPS receiver capable of recording locational position to the accuracy stated
in CD 535 [Ref 5.N] for condition survey;
3) a connected laser rangefinder with digital compass, or some other means, to remotely locate
inaccessible assets in the carriageway or central reserve; and,
4) the ability to take digital photographs or to link to photographs taken by a digital camera.
6.8.1
The mobile GIS should be preloaded with the following data sets prior to the all assets condition and
connectivity survey (where available):
1) the downloaded DDMS drainage system data (if any);
2) the desk study GIS mapping, aerial photography and other data sets; and,
3) the drainage assets identified in the desk study and access routes.
6.9
A pole-mounted camera with appropriate recording hardware and software shall be used for the
inspection of chambers and pipework.
6.9.1
The pole-mounted camera should be:
1) lightweight;
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2) provided with a portable, daylight viewable screen;
3) colour with a minimum resolution of 0.3 megapixels;
4) equipped with a minimum of 200:1 zoom with integral lighting providing an in-pipe view range of at
least 70m in optimal conditions;
5) provided with the ability to record video and still photographs; and,
6) provided with an integral or supplementary wide angle lens and lighting for the inspection of
chambers.
NOTE
The following equipment can be useful for the field survey:
1) a metal detector for finding buried chamber covers;
2) an appropriate means for opening and lifting chamber covers, depending on the local health and
safety requirements;
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3) binoculars for the remote inspection of inaccessible assets;
4) a means of determining pipe connectivity, either:
a) tracing dye; or,
b) a pipe locator transmitter sonde with push rods and a handheld surface detector.
Method of survey
6.10
Working from the verge, hard shoulder, footpath, adjacent earthworks or adjacent land, and taking
advantage of any overbridges, the surface visible point, continuous and region drainage assets shall be
located or confirmed.
6.10.1
The assets should be located and recorded as follows:
1) locate accessible surface visible point assets by GPS;
2) locate inaccessible surface visible point assets in the carriageway or central reserve by rangefinder
linked to the GPS, or from the aerial photography in the GIS;
3) locate straight surface visible continuous assets by joining the relevant point assets at their ends;
4) locate curved surface visible continuous assets by recording enough points along their length to
define their approximate shape and by using the aerial photography in the GIS; and,
5) for region assets record enough locations to adequately define their shape or trace around the
outline on the aerial photography in the GIS.
6.11
All accessible chamber covers shall be lifted and all incoming and outgoing pipes in the chamber
inspected using the pole-mounted camera.
6.11.1
Access to chambers with bolted covers should be attempted. This may require bolts to be removed
prior to the survey and securely replaced immediately on completion of the survey.
6.12
Where any pipework or culvert is secured behind a trash screen or flap valve the screen or flap valve
shall be lifted or removed to facilitate access, and securely replaced immediately on completion of the
survey.
6.13
For each pipe the pole-mounted camera shall be progressively zoomed along the pipe as far as visibility
permits to assess its condition and to take one or two photographs to illustrate the typical condition.
6.14
All mandatory data fields for asset inventory and survey parameters shall be recorded for all drainage
assets using the codes and formats detailed by the Overseeing Organisations in the NAAs to CD 535
[Ref 5.N].
6.14.1
Where there is no physical point asset at one end of a continuous asset, or it is buried and uncertain
then these point items may be assigned as ghost nodes.
6.14.2
Where the drainage network is dry and the flow direction is not obvious from the configuration of the
assets, then uncertainty in the flow direction should be recorded in accordance with Table 6.14.3.
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6.14.3
6. All assets condition and connectivity survey
The full connectivity of the drainage system should be established by a combination of inspection,
deduction and assumption and be recorded in accordance with Table 6.14.3 as follows:
1) where there is significant uncertainty in the connectivity then dye tracing or a pipe locator sonde is
used to resolve the uncertainty (within the limitations of safe access);
2) extreme uncertainty in the connectivity is indicated using a phantom connector;
3) even where connectivity is uncertain, the flow direction can be certain from an overall understanding
of the drainage network.
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Table 6.14.3 Recording the level of certainty in connectivity and flow direction
Observation
Continuous asset
type and details
Connectivity
certainty
Flow
certainty
Structural and
service grades
Surface ditch or
channel.
Connection certain.
Appropriate asset
type. Record the
mandatory and
optional asset
attributes.
Certain
Likely to be certain
Assign grades 1 to
5
Pipe, both ends
inspected.
Connection certain.
No alternatives
exist.
Appropriate pipe
asset type. Record
the mandatory and
optional pipework
attributes.
Certain
Likely to be certain
Assign grades 1 to
5
A carrier pipe has
been inspected
from one or both
ends. Gullies are
present in the
carriageway but
cannot be
accessed. Gully
connections can be
seen in the carrier
but their condition
cannot be
assessed.
Use the general
pipework asset
type for both the
carrier pipe and
gully connections.
Having seen at
least some of the
gully connections
in the carrier pipe a
reasonable
assumption can be
made on the
location of the
connector node
between the carrier
and the gully
connections.
Record the
mandatory and
optional pipework
attributes for the
carrier. Record
only the mandatory
attributes for the
gully connections.
Likely to be certain
Assign grades 1 to
5 to the carrier and
grade 9 to the gully
connections
Certain
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Table 6.14.3 Recording the level of certainty in connectivity and flow direction (continued)
Observation
Continuous asset
type and details
Connectivity
certainty
Flow
certainty
Structural and
service grades
No inspection
below ground
possible due to
lack of access. A
line of gullies can
be seen along the
central reserve. A
carrier pipe
connecting them is
inferred remotely
from the hard
shoulder.
Use the general
pipework asset
type for the carrier
pipe and record
only the mandatory
pipework
attributes. Use the
connectivity
attribute of the
gully to note its
connection to the
carrier pipe,
without the need to
record gully
connection
pipework or to
define the location
of the connection
between the two.
Certain
Likely to be certain
Assign grade 9 to
the carrier
No inspection
below ground
possible due to
lack of access. Dye
tracing or locator
sonde is either not
possible or has not
resolved the
connections. Two
or more alternative
connections are
possible.
Use the general
pipework asset
type. It is
necessary to make
an assumption at
the most likely
connection.
Record only the
mandatory
pipework attributes.
Uncertain
Can be certain or
uncertain
depending on
understanding of
the overall flow
regime
Assign grade 9
6.14.4
Any optional data fields for asset inventory and survey parameters should be recorded using the codes
and formats detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] so far as this is
possible within the constraints of safe access.
6.15
The overall asset level service and structural condition of every drainage asset shall be assessed in
accordance with the drainage condition grade quick assessment procedure given in Appendix A.
6.15.1
The condition of visible but inaccessible surface assets (such as channels in the central reserve) may
be assessed remotely from the verge or an overbridge with the aid of binoculars.
6.15.2
Where the asset condition cannot be assessed, such as inaccessible chambers in the central reserve
or ditches hidden in dense vegetation, then both condition grades should be recorded as "9".
6.15.3
Where an asset, such as a chamber, is known to exist from the desk study but cannot be found, then
both condition grades should be recorded as "0".
6.15.4
Where either a service or structural condition grade of 4 or 5 is assessed then the most severe defect
or defects that have lead to the grade assessment should be recorded and photographed.
6.16
Digital photographs shall be taken of all priority assets.
6.16.1
Digital photographs should be taken to show typical non-priority assets, and their condition.
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Interruption of survey
6.17
Where the continuation of the survey is prevented by a temporary increase in the flow rate in the
drainage system the survey shall either:
1) move to another location either within the same catchment or another catchment whilst the flow
abates; or,
2) be suspended until the flow has abated where all parts of the drainage systems to be surveyed are
temporarily affected.
6.18
Where access to the pipework is obstructed by silt or muddy water and the pipework cannot be
inspected by the pole camera the survey shall:
1) record the service and structural condition of the chamber;
2) record that the pipework was not accessible for survey (service and structural condition grade 9);
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3) not attempt to clear the chamber;
4) move to the next survey position; and,
5) survey the pipework from adjacent nodes where possible.
6.19
Where a blockage is encountered within pipework the survey shall:
1) record the service and structural condition of the pipework;
2) not attempt to clear the blockage;
3) move to the next survey position;
4) survey the pipework from the opposite end; and,
5) reassess the overall pipework service and structural condition.
6.20
Where a chamber cover or gully grating cannot be removed within 15 minutes the survey shall:
1) record that the node was not accessible for survey (structural and service condition grade 9);
2) move to the next survey position; and,
3) survey the pipework from adjacent nodes.
6.21
Where a chamber is found to be unsafe to use as an access point the survey shall:
1) record the service and structural condition and photograph the chamber from the surface; and,
2) survey the pipework from adjacent nodes.
Quality control requirements
Surveyor competency
6.22
The senior surveyor shall have at least five years experience of surveying highway drainage systems.
6.23
The senior surveyor shall be able to make informed judgement about the nature and connectivity of the
drainage asset for those parts of the drainage system that cannot be directly accessed during the
survey.
6.24
Evidence shall be provided that the surveyor undertaking the pole-mounted camera survey has
received training in the use of the equipment and the interpretation of drainage condition.
NOTE
The OS19X pipe sewer condition classification or OS30X pipe sewer condition conversion
qualifications are appropriate.
Survey method quality control
6.25
As the survey of each drainage catchment is completed, the field GIS map shall be reviewed and any
gaps infilled and any anomalies resolved, before moving on to the next part of the survey.
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NOTE
6. All assets condition and connectivity survey
The survey can be checked for the following:
1) is the drainage network complete?;
2) are there any gaps?;
3) have outfalls and/or soakaways been located?;
4) are the flow directions consistent?;
5) are there areas where the flow direction is uncertain, which can now be reassessed as certain?;
6) are there areas where the connectivity is uncertain, that warrant further inspection, or can now be
reassessed as certain?;
7) have all the mandatory attributes been completed?;
8) has a structural and service grade been assigned to every asset, either 1 to 5, or 9 or 0?; and,
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9) have the optional attributes been completed for all assets that it was possible to access?
Reporting requirements
Data submission
6.26
The survey report shall consist of a submission for upload to the DDMS of the following digital data:
1) the round-tripped DDMS survey data (if any) combined with the new survey data as separate files
for each catchment; and,
2) any digital photographs taken during the survey.
Survey data
6.27
All survey data shall be reported using the standard coding system and nomenclature defined by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
6.28
All recorded survey data shall be submitted for upload to the DDMS in the standard digital format(s)
defined by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
6.29
Where a section of pipework between consecutive nodes is surveyed from each end, then two separate
coding records shall be made and combined to form a single record of the pipework between the two
nodes.
6.29.1
Automated combination of condition records should be carried out by the reporting software or by the
DDMS during data upload.
6.30
Any round-tripped existing drainage data from the DDMS shall retain the unique reference of each
asset.
6.31
New assets added to the data during the survey shall be assigned a field reference that is unique within
the survey.
NOTE
A permanent unique asset reference is automatically assigned by the DDMS when the data is
uploaded.
Photographs
6.32
All photographs shall be:
1) in colour;
2) in JPEG format as .JPG files;
3) submitted for upload to the DDMS as documents attached to the asset to which they relate;
4) at a resolution of at least 1.0 megapixels, and,
5) indexed in the coded data.
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7.
7. Pipework and chambers defect survey by CCTV
Pipework and chambers defect survey by CCTV
Survey requirements
Scope of survey
7.1
A pipework and chambers defect survey shall be carried out to determine the inventory, condition and
detailed defects of pipework and the associated chambers and gullies, including the use of a
closed-circuit television (CCTV) camera.
7.2
A pipework and chambers defect survey by CCTV shall include the following:
1) details of the location, date, equipment and personnel of the survey;
2) details of any pre-cleansing, removal of blockages, root cutting or other associated works carried out;
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3) survey of the required pipework and/or culverts;
4) survey of all chambers and gullies connected to the required pipework and/or culverts and
associated interconnections;
5) survey of the location of all chambers and gullies and the levels of chamber covers, gully gratings,
chamber inverts, gully inverts and the inverts of pipework connections;
6) identification of the asset type of all surveyed assets in accordance with the classification system
detailed in CD 535 [Ref 5.N];
7) recording of all the mandatory and optional data fields for asset inventory, structural condition
defects, service condition defects, and survey parameters using the codes detailed by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] for all pipework and/or culverts,
chambers and gullies surveyed;
8) recording of an overall asset level structural and service condition grade;
9) recording of an in-pipe video showing the nature of the pipework and the defects recorded;
10) taking of still photographs from the in-pipe video showing the nature of typical pipework and specific
defects recorded;
11) taking of still photographs showing the typical nature and specific defects of the chambers and
gullies surveyed; and,
12) submission of a digital report and digital data sets in the formats defined by the Overseeing
Organisations in the NAAs to CD 535 [Ref 5.N] and as detailed in the reporting requirements below.
NOTE
A pipework and chambers defect survey by CCTV is:
1) a field survey carried out where full and detailed knowledge of the condition and defects of the below
ground pipework is needed;
2) carried out because, either;
a) there is a known problem with the performance of the pipework that needs to be understood; or,
b) there is flooding or defects in other assets that are suspected to be due to defective pipework; or,
c) an all assets condition and connectivity survey has indicated a structural or service grade of 4 or
5 within the pipework that requires further investigation; or,
d) repair, replacement or redesign of the drainage system is being investigated; or
e) for contractual certification of new build drainage works; and,
3) applicable in all forms of pipework up to 900 mm in diameter and in culverts up to 1800 mm in
diameter.
7.2.1
A pipework and chambers defect survey by CCTV may have the following associated surveys:
1) a pipework geometric survey by laser profiler; and/or,
2) a pipework inclination survey.
7.2.2
A pipework and chambers defect survey by CCTV may include the following:
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1) the provision of traffic management; or,
2) restrictions to the work programme and/or working hours.
Survey data round-tripping
7.3
Survey data shall be round-tripped from the DDMS where available.
7.4
Where there is some drainage inventory information in the catchment(s) to be surveyed on the DDMS
the survey shall round-trip this data in accordance with specific procedures and formats detailed by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] by:
1) downloading the available information;
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2) confirming or updating the inventory, condition and defects of the pipework, culverts and associated
chambers and gullies in the field;
3) retaining as part of the data, without change, any inventory and condition information on any
non-surveyed assets; and,
4) the submission for uploading of this information to the DDMS.
7.5
Where there is no drainage inventory information in the catchment(s) to be surveyed on the DDMS the
survey shall consist of the following:
1) a first-time survey of the inventory, condition and defects of the pipework, culverts and associated
chambers and gullies; and,
2) the submission for upload of this information to the DDMS in accordance with specific procedures
and formats detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
NOTE
Additional activities required to complete the round-tripping of drainage information to the DDMS are
provided in the NAAs to CD 535 [Ref 5.N].
Survey equipment
7.6
The CCTV equipment shall be capable of surveying:
1) a length of pipework of at least 350 metres where the pipework can be accessed from either end;
2) a length of pipework of at least 200 metres where a self-propelled camera is used and access is
gained from only one end; or,
3) a length of pipework of at least 30 metres where a rodding camera is used.
7.7
The CCTV camera shall be:
1) crawler-, tractor- or sledge-mounted;
2) equipped with a jack-up facility where larger diameter pipes are to be surveyed;
3) equipped with integral lighting unit;
4) certified for use in either Zone 1 or Zone 2 potentially explosive environments;
5) equipped with a pan, tilt and zoom facility capable of 90 degrees tilt and 360 degrees rotation, or a
fixed head panoramic view;
6) colour, solid state, with a resolution of at least 0.4 megapixels;
7) capable of producing a clear, accurate and in-focus record of the internal condition of the pipework
from 150 mm in front of the camera to infinity;
8) equipped with a cable connecting the camera to the surface control unit through a counter to
determine the camera location;
9) set up to pass through the pipework being surveyed in a stable manner;
10) positioned so as to minimise the risk of picture distortion by being positioned centrally within the
pipework (utilising a jack-up camera for larger diameter pipes) to within a positioning tolerance of
±10% of the vertical pipework dimension and looking along the axis of the pipework; and,
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11) set up so that all bonds, guide ropes and cables are supported away from the walls of the pipework
and chambers.
7.8
The location of the CCTV camera within the pipework shall be measured to an accuracy of ± 1% the
length of the pipe run or 0.3m, whichever is the greater, with the counter reading at the start of the
survey run set to zero by allowing for the distance from the start of the survey run to the cable
calibration point.
7.9
The CCTV monitor shall display an automatically updated record of the following reference information
which is to be shown on the recorded video and photographs:
1) the chamber reference at the start of the survey run;
2) the chamber reference at the end of the survey run (whether the chamber is reached or not);
3) the pipe reference;
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4) the survey direction;
5) the survey run reference (to distinguish multiple survey runs on the same pipe in the same direction);
6) the chainage of the camera position from the calibration point in metres and tenths of a metre; and,
7) the date of survey.
7.10
The computer-based CCTV recording equipment shall be capable of the following:
1) digitally recording a video of the CCTV image overlaid with the reference information;
2) digitally recording still photographs from the video overlaid with the reference information;
3) recording the CCTV surveyor's interpretation of the inventory and condition of the pipework using
the codes detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N]; and,
4) linking the recorded video and still photographs to the coded data.
7.11
Topographic survey equipment shall be provided to measure locations and levels to the accuracy
stated in CD 535 [Ref 5.N] for detailed survey and to the national survey grid and national survey datum
stated by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
7.12
Facilities shall be provided for the forced ventilation of pipework or culverts where necessary to
complete the survey.
Method of survey - pipework CCTV
7.13
Pre-cleansing of the drainage system shall be carried out where necessary to complete the survey.
7.14
Pre-cleansing shall be carried out in accordance with the MCHW Series 0500 [Ref 15.N] clauses on the
cleaning of existing drainage systems and low-pressure, high-volume jetting of drainage systems,
utilising recycling jet-vac tankers.
7.15
The location and depths of silt removed by pre-cleansing shall be recorded and reported.
7.15.1
Pre-cleansing can remove evidence of siltation problems or other service defects that affect the
performance of the pipework and should only be carried out where it is known that the silt level
prevents access by the CCTV camera.
7.16
The pipework shall be vented to remove potentially noxious or explosive gases by raising the covers at
both ends of the length to be surveyed.
7.17
Where any pipework or culvert is secured behind a trash screen or flap valve the screen or flap valve
shall be lifted or removed to facilitate access, and securely replaced immediately on completion of the
survey.
7.18
The inventory and condition of all required pipework lengths shall be surveyed by CCTV and reported
by recording on site all of the mandatory and optional data fields for asset inventory, structural condition
defects, service condition defects, and survey parameters using the codes detailed by the Overseeing
Organisations in the NAAs to CD 535 [Ref 5.N].
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7.19
At each chamber or other access point, new pipework header details shall be recorded, except for gully
connections which are recorded in accordance with CD 535 [Ref 5.N].
7.20
Where buried chambers are encountered during the survey, the camera shall be panned to allow
recording of the internal inventory and condition of the chamber.
7.21
Where the survey continues through a chamber or other access point, the meterage shall be reset to
zero with the camera focused on the outgoing pipe entrance.
7.22
The length of pipework shall be measured between the exit face of one chamber and the point of entry
to the next chamber.
7.23
The speed of the camera within the pipework shall be limited to the following maximum speeds:
1) 0.10 m/s for pipework of diameter less than 200 mm;
2) 0.15 m/s for pipework of diameters of 200 mm or larger, but less then 310 mm; and,
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3) 0.20 m/s for pipework or culverts of diameter 310 mm and larger.
7.24
The camera shall be stationary whenever defect observations are being recorded.
7.25
Where a camera with a pan-and-tilt head is used the camera shall:
1) only be moved forward when the lens is pointing forward in the direction of the axis of the pipework;
and,
2) be stopped and panned around the circumference of the whole pipe to inspect a defect or
connection.
7.26
Still photographs shall be taken of the internal condition of the pipework as follows:
1) at the start of all continuous defects, and thereafter every five metres;
2) for non-brick pipework or culverts at every crack, fracture, broken pipe, deformation, collapse and
severe joint displacement;
3) for brick pipework or culverts at every crack, fracture, missing or displaced brick, deformation,
collapse, dropped invert and mortar loss;
4) at any other structural or service defect that would lead to the overall grading of the pipework or
culvert being 3, 4 or 5;
5) at intervals not less than two metres where defects exist at adjacent points unless necessary to
show the second defect;
6) to show the general condition at intervals of not more than 10 metres where there are no defects;
7) at abandonment; and,
8) all photographs are recorded in the coded data.
7.27
All equipment and debris shall be removed from site at the end of each shift, or sooner.
Method of survey - chambers
7.28
All chamber covers and gully gratings shall be removed and replaced to gain access for the survey.
7.28.1
Access to chambers with bolted covers should be attempted. This may require bolts to be removed
prior to the survey and securely replaced immediately on completion of the survey.
7.29
The inventory and condition of all chambers and gullies connected to the required pipework shall be
surveyed by visual inspection from the surface and reported by recording on site all of the mandatory
and optional data fields for asset inventory, structural condition defects, service condition defects, and
survey parameters using the codes detailed by the Overseeing Organisations in the NAAs to CD 535
[Ref 5.N].
7.30
The location of all chambers shall be surveyed to the accuracy stated in CD 535 [Ref 5.N] for detailed
survey and to the national survey grid stated by the Overseeing Organisations in the NAAs to CD 535
[Ref 5.N].
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7.31
The level of all chamber covers, gully gratings, manhole inverts, gully sumps, catchpit sumps, inverts of
all incoming and outgoing pipework connections in every chamber shall be surveyed to the accuracy
stated in CD 535 [Ref 5.N] for detailed survey and to the national survey datum stated by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
7.32
Photographs shall be taken of all chambers and gullies surveyed as follows:
1) general location photograph of the chamber/gully prior to removal of the cover/grating;
2) vertical photograph looking down the chamber/gully with cover/grating removed, prior to any
cleaning;
3) vertical photograph looking down the chamber/gully with cover/grating removed, following any
cleaning;
4) additional photographs to show specific defects;
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5) orientation of photographs to be recorded along with direction of flow; and,
6) photographs 1) to 3) above to be recorded as "general photograph" observations.
Interruption of survey
7.33
Where the continuation of the survey is prevented by a temporary increase in the flow rate in the
drainage system the survey shall either:
1) attempt to manage the flow within the pipework by means of temporary stoppers for limited periods
to facilitate the survey without causing flooding or pollution of receiving waters; or,
2) move to another location whilst the flow abates; or,
3) be suspended until the flow has abated.
7.34
Where the continuation of the survey is prevented by a blockage in the drainage system, the survey
shall proceed where specified in the task order, by either:
1) do not attempt to remove the blockage and survey the pipework run from the other direction; or,
2) move to an another location whilst the blockage is cleared by others as arranged by the Overseeing
Organisation's representative; or,
3) survey the pipework run from the other direction, then proceed to remove the blockage by cleansing
as follows:
a) cleansing of catchpits and manholes to be in accordance with the MCHW Series 0500 [Ref 15.N]
clauses on the cleaning of existing drainage systems;
b) cleansing of pipework to consist of low-pressure/high-volume jetting in accordance with the
MCHW Series 0500 [Ref 15.N] clauses on low- pressure/high-volume jetting of drainage
systems; and,
c) jetting nozzle pressures are not to exceed 127 bar/1900 psi or any lower value stated in the
MCHW Series 0500 [Ref 15.N] clauses on low-pressure, high-volume jetting of drainage
systems.
7.35
Where initial inspection indicates root blockage or partial blockage, root cutting shall be carried out
where specified in the task order and the pipework resurveyed, by either:
1) jetting with the nozzle pressures not to exceed 127 bar (1900 lbf/in2) or any lower value stated in the
MCHW Series 0500 [Ref 15.N] clauses on low- pressure/high-volume jetting of drainage systems; or,
2) flail; or,
3) other form of cutter.
7.36
Where a chamber cover or gully grating cannot be removed within 15 minutes, the survey shall:
1) survey the node by CCTV from the adjacent nodes; or
2) where surveying of the node is not possible, record that the node was not accessible for survey
(structural and service condition grade 9) and move to the next node.
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7. Pipework and chambers defect survey by CCTV
Where a chamber is found to be unsafe to use as an access point then the survey shall:
1) record the service and structural condition and photograph the chamber from the surface; and,
2) survey the pipework from adjacent nodes.
7.38
Where continuation of the survey is prevented by temporary traffic conditions, parked vehicles or other
obstructions, or changes in the traffic management arrangements the surveyor shall either:
1) attempt to resolve the matter with those responsible for traffic management as detailed in the task
order; or,
2) move to another location whilst the matter is resolved; or,
3) suspend the survey until the matter is resolved.
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Abandonment of survey
7.39
A survey run of any pipework length shall be abandoned for any of the following reasons:
1) it is not possible to maintain acceptable picture quality due to the condition of the pipework;
2) a situation occurs that places the survey equipment or personnel at risk;
3) further progress is impossible;
4) it is not possible to locate the access point;
5) it is not possible to lift the access chamber cover;
6) it would be unsafe to access the pipework due to the condition of the access chamber;
7) it is not possible to survey from the chamber or continue the survey due to blockage, silt or high
water level;
8) a dangerous atmosphere is identified in the pipework; or,
9) there is a risk to the structural integrity of the pipework.
7.40
Where a survey run has the potential to be abandoned then the following shall be carried out:
1) recording of the situation on the survey record;
2) photographing of the issue;
3) adoption of the procedures for interruption of survey prior to abandonment; and,
4) only where the interruption of survey procedures are unsuccessful or not possible is the survey of
this section of pipework to be abandoned and the Overseeing Organisation's representative
informed.
Quality control requirements
Surveyor competency
7.41
Evidence shall be provided that the surveyor undertaking the CCTV survey holds an appropriate
qualification in the interpretation of CCTV images of pipework and in defect coding and classification.
NOTE
The OS19X pipe sewer condition classification or OS30X pipe sewer condition conversion
qualifications are appropriate.
7.42
Evidence shall be provided that the surveyor undertaking the location and level topographic survey
holds an appropriate qualification in topographic surveying.
7.43
Where any working within confined spaces is required, evidence shall be provided that those staff
involved have received appropriate confined space training.
7.44
A quality control system approved by the Overseeing Organisation's representative shall be maintained
to control the accuracy of the CCTV interpretation and reporting consisting of the following:
1) monitoring a 5% sample of each surveyor's work;
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2) selecting the sample randomly from the sequence of work carried out by each surveyor;
3) independent review of the video recordings against the coded data in the sample;
4) derivation of header accuracy as the proportion of entries made in the header fields which are
entered using the correct symbols or codes, for the sample;
5) derivation of the detailed survey accuracy as the proportion of entries that are correct, with any
missing entry regarded as incorrect, for the sample;
6) where the accuracy of either the header information calculated for any of the sampled surveys falls
below 95% or the coded detailed survey information calculated for any survey falls below 85%, an
additional check is carried out;
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7) the additional check comprising the five surveys of pipework lengths carried out by that surveyor
immediately preceding the failed survey and the five surveys carried out by that surveyor
immediately following the failed survey;
8) where any of these additional checks fail then the process is repeated using a further five
before-and-after surveys, until the required accuracy is achieved; and,
9) the individual check results for both the header and detailed survey information and the rolling
average of both of these over each five consecutive checks is plotted on a graph and reviewed.
7.45
A CCTV surveyor whose header quality control results fall below 95% or whose detailed survey quality
control results fall below 85% on more than two occasions in a 3-month period, or whose rolling average
for either check falls below these criteria, shall be deemed to have failed the quality control criteria.
7.46
A CCTV surveyor who fails the quality control criteria shall be invalidated from acting as a surveyor on
any contract until they have re-attended and re-passed the relevant training.
7.47
Any CCTV survey reports failing the coding accuracy shall be re-coded by another qualified surveyor
and resubmitted as a replacement for the failed survey.
Survey method quality control
7.48
A method statement shall be provided and approved prior to the commencement of the works that
includes the following:
1) a statement of full compliance with this specification or a clear list of any qualifications or
non-compliance of either equipment or procedures, and a full method statement of any alternatives
proposed;
2) the type and version of the CCTV survey software;
3) evidence of compliance of the equipment with SI 2016/1107 [Ref 22.N]; and,
4) any sub-contractors that are to be used and a description of their role.
7.49
The accuracy of the linear measurement of the camera position shall be checked and recorded by the
procedure for camera cable calibration defined in WRC's Manual of Sewer Condition Classification
MSCC5 2013 [Ref 17.N].
7.50
Where the linear measurement of the camera position falls outside of the required accuracy the
pipework shall be resurveyed.
7.51
The camera shall be set up in the pipework at the start of each survey run by the procedures defined in
MSCC5 2013 [Ref 17.N] for the following:
1) centring the camera;
2) measuring the offset distance of the camera; and,
3) positioning the camera at the start of the pipe.
CCTV picture quality control
7.52
The electronic equipment, camera and monitor shall be set up and tested by the procedures defined in
MSCC5 2013 [Ref 17.N] for the following:
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1) video display screen test;
2) camera test; and,
3) lighting test.
Reporting requirements
Data submission
7.53
The survey report shall consist of the following digital data split into drainage catchments suitable for
upload to the DDMS:
1) coded survey data in the digital format(s) defined by the Overseeing Organisations in the NAAs to
CD 535 [Ref 5.N], as detailed in the survey data requirements;
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2) video recordings referenced in the coded survey data, as detailed in the video recordings
requirements;
3) photographs referenced in the coded survey data, as detailed in the photographs requirements.
7.53.1
A summary report in PDF format may additionally be provided, including the following:
1) a description of the survey carried out, its location, and the equipment and methods used;
2) details of the quality control procedures;
3) a schematic drawing of each section of pipework or culvert surveyed showing the reference number,
diameter and material of the pipe, the location and nature of each structural and service defect, the
position of any adjoining connections, the reference numbers of the chamber/node at each end, the
flow direction and the overall structural and service grade of the pipe;
4) a schematic drawing of each chamber in plan and section showing the position, references and
invert levels of all incoming and outgoing pipes, the level of any water and/or silt, the position and
nature of any defects and the overall structural and service grade of the chamber;
5) details of the coded defects for each asset surveyed in tabular format;
6) a summary table of all pipework/culverts surveyed (including abandoned surveys) detailing the pipe
asset reference, the asset references of the upstream and downstream chambers, the upstream and
downstream invert levels, the survey direction, date, the pipe shape, size and material, the total
length of the pipe, the length of the pipe surveyed, the overall structural and service grade;
7) a summary table of abandoned pipework/culvert surveys detailing the pipe asset reference, the
asset references of the upstream and downstream chambers, total length of the pipe, surveyed
length at abandonment, reason for abandonment;
8) a summary table of pipe jetting and root cutting detailing the pipe asset reference, the asset
references of the upstream and downstream chambers, the cleansing direction, date, start of
blockage (in metres), end of blockage (in metres), length jetted (in metres), duration of root cutting,
equipment used, maximum pressure used, nature of blockage and outcome;
9) a summary table of all chambers and gullies surveyed detailing the asset reference, asset type,
cover level, invert level, the overall structural and service grade; and,
10) an indicative schedule of remediation options for all assets with a service or structural grade of 4 or
5.
NOTE
The indicative schedule of remediation options is to provide a basic, non-prescriptive statement of
potential works and carries no design liability or certainty of adoption.
7.53.2
Three sets of CAD drawing files in DWG, DXF and PDF formats may be additionally provided, showing
the following:
1) survey inventory drawings, showing:
a) the extent of the completed survey;
b) the location, asset type, unique reference number, and layout of each drainage asset surveyed;
c) the connectivity and flow direction between assets;
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d) any errors in any provided drawings or layout data noted during the survey; and,
e) overlaid on available base mapping showing the highway, highway boundary, structures and
other reference features of the surveyed corridor and the national grid.
2) survey condition drawings, showing:
a) the overall service and structural condition grade of each asset;
b) location and nature of defects in grade 4 and 5 assets;
c) survey abandonments; and,
d) overlaid on available base mapping showing the highway, highway boundary, structures and
other reference features of the surveyed corridor and the national grid; and,
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3) survey level drawings, showing:
a) cover and invert levels of chambers;
b) invert levels, pipe size and pipe material of pipework;
c) flow direction; and,
d) overlaid on available base mapping showing the highway, highway boundary, structures and
other reference features of the surveyed corridor and the national grid.
Survey data
7.54
All survey data shall be reported using the standard coding system and nomenclature defined by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
7.55
All coding shall be directly entered into a computer or handheld device that restricts entries to valid
codes.
7.56
Where the survey is round-tripping existing drainage data from the DDMS the unique reference of each
asset shall be retained in the round-tripped data.
7.57
Where new assets are added to the data during the survey they shall be assigned a field reference that
is unique within the survey.
NOTE
A permanent unique asset reference is automatically assigned by the DDMS when the data is
uploaded.
7.58
At the commencement of the survey of every length of pipework or culvert between consecutive access
points, the surveyor shall complete new header information in accordance with the requirements of the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
7.59
Where different observation types occur at the same point each shall be coded separately.
7.60
Where a continuous observation changes in nature along its length, the change shall be coded
separately.
7.61
The length of pipework shall be measured between the exit face of the chamber and the point of entry
to the next chamber.
7.62
Where a section of pipework is surveyed more than once either due to obstruction or equipment
difficulties then the last survey run shall be reported.
7.63
Where a section of pipework between consecutive nodes is surveyed from each end due to obstruction,
then two separate coding records shall be made and combined to form a single record of the pipework
between the two nodes.
7.63.1
Automated combination of condition records should be carried out by the reporting software or by the
DDMS during data upload.
7.64
Each of the defects recorded shall be scored in accordance with the scoring system detailed by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] for all pipework and/or culverts, chambers
and gullies surveyed.
7.64.1
Automated condition scoring should be carried out by the recording software or by the DDMS during
data upload.
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7.65
The overall asset level structural and service condition grade shall be derived by aggregating the
scores for each recorded defect in accordance with the aggregating procedure detailed in CD 535 [Ref
5.N] for all pipework and/or culverts, chambers and gullies surveyed.
7.65.1
Automated aggregation of the scores to determine the overall asset level structural and service
condition grades should be carried out by the CCTV software or by the DDMS during data upload.
7.66
All recorded survey data shall be submitted for upload to the DDMS in the standard digital format(s)
defined by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
7.66.1
The survey data may also be provided packaged with any proprietary software viewer necessary to
view all of the data in accordance with the following:
1) all of the coded data (both header and detailed defect observations) for every inspection carried out
on every section of pipework, culvert, chamber, and gully, including repeat inspections;
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2) all of the associated photographs and videos;
3) facilities that allow the survey data to be viewed in conjunction with the video and photographs, such
that viewing an asset or observation in the data will automatically retrieve the associated section of
video and relevant photographs; and,
4) an unrestricted licence for the use of the software viewer.
7.66.2
Items of the survey data may be supplied in advance of the formal report during the course of the
survey.
Video recordings
7.67
All video recordings shall be:
1) in colour;
2) in MPEG format as .MPG files;
3) at a resolution of at least 0.4 megapixels;
4) at a frame rate of at least 25 frames per second; and,
5) indexed in the coded data.
Photographs
7.68
All photographs taken shall be submitted for upload to the DDMS as documents attached to the asset
to which they relate.
7.69
All photographs shall be:
1) in colour;
2) in JPEG format as .JPG files;
3) at a resolution the same as the video recording for CCTV survey;
4) at a resolution of at least 1.0 megapixels for all other photographs; and,
5) indexed in the coded data.
CAD drawing files
7.70
All CAD drawing files shall be produced in accordance with GG 184 [Ref 20.N].
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8. Pipework geometric survey by laser profiler
Pipework geometric survey by laser profiler
Survey requirements
Scope of survey
8.1
A pipework geometric survey shall be carried out to determine the pipework internal circumferential
geometry, including the use of a laser profiler in association with a pipework and chambers defect
survey by CCTV.
8.2
A pipework geometric survey by laser profiler shall include the following:
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1) the survey of the internal circumferential pipework geometry;
2) the recording of any additional mandatory and optional data fields for asset inventory, structural
condition defects, service condition defects and survey parameters either not recorded or not fully
quantified by the associated CCTV survey, and the merging of these observations into the CCTV
coded data using the codes detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref
5.N]; and,
3) the assessment and reporting of internal pipework diameter, cross sectional area, ovality and
surface irregularities.
NOTE
A pipework geometric survey by laser profile is carried out:
1) in association with a pipework and chambers defect survey by CCTV;
2) where continuous measurement of the internal geometry of the below- ground pipework is required;
and,
3) in all forms of pipework up to 900 mm in diameter and in culverts up to 1800 mm in diameter.
Survey data round-tripping
8.3
Survey data shall be round-tripped from the DDMS, where available, in accordance with the
requirements for pipework and chambers defect survey by CCTV.
Survey equipment
8.4
A laser profiler shall be:
1) attached to a crawler, tractor or sledge-mounted CCTV camera;
2) equipped with a single or multiple laser sources (as suited to the diameter of the pipework) to define
a bright ring of light on the internal circumference of the pipework within the view of the CCTV
camera;
3) certified for use in either Zone 1 or Zone 2 potentially explosive environments; and,
4) capable of recording the pipework internal circumferential profile to an accuracy of +/-1%, at
intervals of no more than 10 mm along the length of the pipework, with a resolution of at least 180
data points per profile.
Method of survey
8.5
Pre-cleansing of the drainage system shall be carried out where necessary to complete the survey.
NOTE
Optimum laser profile results are obtained in clean and dry pipes, but the use of pre-cleansing can be
at variance with the optimum conditions for recording service condition by the associated CCTV survey.
8.6
The internal circumferential geometry of the pipework shall be surveyed by laser profiler making two
passes along the pipe length, one with the CCTV lights on and one with them off, traversing the pipe at
a constant speed.
8.7
The distance recording shall be synchronised for:
1) the two passes along the pipework;
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2) between observations made from the CCTV video; and,
3) those made from the laser profile interpretation, allowing for the offset of the laser in front of the
camera.
Interruption of survey
8.8
Interruptions to the survey shall be defined and managed in accordance with the requirements for
pipework and chambers defect survey by CCTV.
Abandonment of survey
8.9
Abandonment of the survey shall be defined and managed in accordance with the requirements for
pipework and chambers defect survey by CCTV.
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Quality control requirements
Surveyor competency
8.10
Evidence shall be provided that the surveyor undertaking the laser profile survey has received training
in the use of the equipment and the interpretation of the results.
Survey method quality control
8.11
The calibration of the measurement of internal pipework diameter by the laser profiler shall be checked
and recorded at the start of each survey run by:
1) manually measuring the pipework diameter along two diameters at right angles; and,
2) using a calibration scale placed on the laser head.
8.12
Evidence shall be provided of compliance of the equipment with the SI 2016/1107 [Ref 22.N]
Regulations.
8.13
The associated CCTV camera and video recording shall be set to its maximum visual resolution.
8.14
The summary outputs of diameter, cross sectional area, ovality and unwrapped irregularity shall be
annotated where the results are misleading due to water and/or sediment in the pipe invert or other
factors.
Reporting requirements
Data submission
8.15
The survey report shall consist of the following digital data split into drainage catchments suitable for
upload to the DDMS:
1) a summary report in PDF format, as detailed in the report requirements;
2) the coded survey data merged into the coded survey data from the CCTV survey, as detailed in the
survey data requirements; and,
3) CAD drawing files, as detailed in the CAD drawing file requirements.
Report
8.16
A summary survey report shall be provided in PDF format including the following:
1) a description of the survey carried out, its location, and the equipment and methods used;
2) details of the quality control procedures;
3) graphical plots showing the average, minimum and maximum internal diameter as a percentage
(positive or negative) change from the nominal undeformed diameter along the length of each
surveyed pipe (measured in metres from the upstream end);
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4) graphical plots showing the percentage change in cross-sectional area (positive or negative) from
the nominal undeformed cross-sectional area along the length of each surveyed pipe (measured in
metres from the upstream end);
5) graphical plots showing the percentage ovality along the length of each surveyed pipe (measured in
metres from the upstream end) for those pipes that were originally circular in cross section; and,
6) coloured graphics showing irregularities in the internal circumferential surface of each pipe
unwrapped as a flat representation, colour coded with the (positive and negative) percentage
difference from the nominal undeformed radius along the length of each surveyed pipe (measured in
metres from the upstream end).
NOTE
mean
Percentage ovality of the original pipe is defined as: △ = 100 ∗ DmaxD−D
, where Dmax is the maximum
mean
internal diameter and Dmean is the mean internal diameter (see ASTM International Standard Practice
document ASTM F1216-16 [Ref 2.I]))
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Survey data
8.17
All coded survey data shall be reported merged with the CCTV coded data in accordance with the
requirements for pipework and chambers defect survey by CCTV.
8.17.1
The survey data may also be provided packaged with any proprietary software viewer necessary to
view all of the data in accordance with the following:
1) the individual circumferential profiles for all locations along each pipe with facilities to carry out
manual measurements from the profiles;
2) for each pipe the summary diameter, cross-sectional area, ovality and unwrapped irregularity
graphics defined for the summary PDF report;
3) a 3D graphical representation of the internal surface of each pipe colour coded with the (positive and
negative) percentage difference from the nominal undeformed radius that can be viewed from
various angles and at various magnifications;
4) facilities that allow the summary survey data to be viewed in conjunction with, and linked to, the
individual circumferential profiles, the CCTV video and photographs, and the coded observations;
and,
5) an unrestricted licence for the use of the software viewer.
CAD drawing files
8.18
A CAD drawing file of the 3D graphical representation of the internal surface of each surveyed pipe
shall be provided in DWG, DXF and PDF file formats.
8.19
All CAD drawing files shall be produced in accordance with GG 184 [Ref 20.N].
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9.
9. Pipework inclination survey
Pipework inclination survey
Survey requirements
Scope of survey
9.1
A pipework inclination survey shall be carried out to determine pipework inclination in association with a
pipework and chambers defect survey by CCTV.
9.2
A pipework inclination survey shall include the following:
1) survey of the inclination of the pipework;
2) the recording of additional data fields for pipework inclination, and the merging of these observations
into the CCTV coded data using the codes detailed by the Overseeing Organisations in the NAAs to
CD 535 [Ref 5.N]; and,
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3) the reporting of pipework inclination.
NOTE 1
A pipework inclination survey is carried out:
1) in association with a pipework and chambers defect survey by CCTV;
2) where continuous measurement of pipework level is required relative to the surveyed level of each
end of the pipe run;
3) to identify:
a) sags or backfalls in the pipe run that would prevent it from being self-cleaning; or
b) compliance with construction tolerances on pipework gradient; and,
4) in all forms of pipework up to 900 mm in diameter and in culverts up to 1800 mm in diameter that are
longer than 10m, have an overall gradient of less than 10% (1 in 10, or about 6 degrees), have a
smooth invert and that have been pre-cleaned.
NOTE 2
A pipework inclination survey is not suitable for:
1) short pipe lengths,(less than about 10m) due to cable drag or pull at the start of the survey run;
2) steeply inclined pipes, such as connections from a gully to the main collector, due to the limited
angular measurement range of the inclinometer;
3) corrugated steel, twin-wall or other forms of pipe where the invert is not smooth; nor,
4) pipework with sediment in the invert.
Survey data round-tripping
9.3
Survey data shall be round-tripped from the DDMS, where available, in accordance with the
requirements for pipework and chambers defect survey by CCTV.
Survey equipment
9.4
In addition to the requirements for pipework and chambers defect survey by CCTV, the CCTV camera
shall be:
1) crawler- or tractor-mounted; and,
2) equipped with an integral inclinometer capable of measuring:
a) longitudinal inclination to an accuracy of better than 0.3% (1 in 333, or about 0.2 degrees); and,
b) up to a maximum angle of 20% (1 in 5, or about 11 degrees) from the horizontal.
9.4.1
The camera should be connected to an auto-wind cable drum and fitted with an integral roll sensor, if
available.
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Method of survey
9.5
A pipework and chambers defect survey by CCTV shall precede the inclination survey to confirm that
the pipe invert is clean and smooth.
9.6
If the CCTV survey indicates that the pipe run is not clear of sediment pre-cleansing shall be carried out
in accordance with the requirements for pipework and chambers defect survey by CCTV.
9.7
The inclination survey shall be carried out at a steady speed of camera travel and without interruption
from one end of the pipe run to the other.
NOTE 1
An uninterrupted steady speed of travel is most easily achieved when the camera is driven in reverse
from the end of the CCTV survey run back to the insertion point, which requires an auto-wind cable
drum.
NOTE 2
Where the CCTV survey is carried out from both ends of the pipe run due to a blockage mid-way along
the pipe the accuracy of the inclination survey will be reduced.
9.7.1
Where fitted, the roll sensor should be continuously monitored to ensure that the camera runs in the
pipe invert and does not climb the pipe wall.
9.8
Drag or pull from the camera cable shall be minimised.
NOTE
Drag or pull from the camera cable is most easily minimised by:
1) taking particular care with the initial camera set-up;
2) installing guide rollers for the camera cable at the top and bottom of the access chamber;
3) utilising an auto-wind cable drum; and,
4) ensuring that the speed of cable feed/retrieval is matched to the speed of camera travel.
9.9
The inclination shall be recorded every time the measured inclination changes.
9.10
The invert level of the pipe run shall be surveyed in the chambers at both ends in accordance with the
requirements for pipework and chambers defect survey by CCTV.
NOTE
If the pipe run is not accessible at one end and the invert level cannot be surveyed it is not possible to
produce the required output of pipe invert absolute level.
Interruption of survey
9.11
Interruptions to the survey shall be defined and managed in accordance with the requirements for
pipework and chambers defect survey by CCTV.
Abandonment of survey
9.12
Abandonment of the survey shall be defined and managed in accordance with the requirements for
pipework and chambers defect survey by CCTV.
Quality control requirements
Surveyor competency
9.13
Evidence shall be provided that the surveyor undertaking the pipework inclination survey has received
training in the use of the equipment and the interpretation of the results.
Survey method quality control
9.14
Evidence shall be provided that the inclinometer has been calibrated by the supplier or manufacturer
within the previous 12 months, or following service or repair, if more recent than 12 months.
9.15
The inclinometer shall be rezeroed at the start of each pipe survey by:
1) setting up the camera in the configuration for the pipe to be surveyed; and,
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2) placing the camera on a precisely levelled surface and rezeroing the inclinometer.
9.16
The digital outputs of a pipework inclination survey shall be annotated where the results are considered
incomplete, misleading or inaccurate due to either:
1) sediment in the pipe invert;
2) drag or pull from the camera cable;
3) roll of the camera from the invert;
4) lack of surveyed pipe invert levels in the end of run chambers;
5) segments of pipe that are steeper than the range capability of the inclinometer;
6) pipe surveyed from both ends due to blockage;
7) debris build-up on the camera tractor wheels; or,
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8) other factors.
Reporting requirements
Data submission
9.17
The survey report shall consist of the following digital data split into drainage catchments suitable for
upload to the DDMS:
1) a summary report in PDF format, as detailed in the report requirements;
2) the coded survey data merged into the coded survey data from the CCTV survey, as detailed in the
survey data requirements.
Report
9.18
A summary survey report shall be provided in PDF format including the following:
1) a description of the survey carried out, its location, and the equipment and methods used;
2) details of the quality control;
3) graphical plots showing schematically the invert level determined from the inclinometer survey with:
a) the data fitted to the measured invert levels in the chambers at each end of the pipe run;
b) vertical axis scale of absolute reduced level in metres to the national survey datum stated by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N];
c) horizontal axis scale of distance along the pipe run from the upstream end, reading from left to
right, labelled upstream on the left and downstream on the right;
d) grid lines for both the reduced level and distance scales;
e) idealised straight-line invert and crown of the pipe interpolated from the invert levels and
diameters determined in the chambers at both ends of the pipe run; and
f) arrows indicating the direction of CCTV survey and the direction of inclination survey along the
pipe run; and,
4) graphical plots showing schematically the invert level determined from the inclinometer survey as
above, with an overlay of camera inclination, plotted against a vertical axis scale of camera
inclination in percent.
Survey data
9.19
The following coded survey data shall be reported merged with the CCTV coded data in accordance
with the requirements for pipework and chambers defect survey by CCTV:
1) maximum pipe gradient in percent (to two decimal places) looking in a downstream direction,
recorded at the distance along the pipe at which it occurs;
2) minimum pipe gradient in percent (to two decimal places) looking in a downstream direction,
recorded at the distance along the pipe at which it occurs;
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3) average pipe gradient in percent (to two decimal places) looking in a downstream direction,
recorded at the start of the pipe run; and,
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4) maximum offset in millimetres (to zero decimal places), from the idealised straight-line invert of the
pipe interpolated from the invert levels determined in the chambers at both ends of the pipe run,
recorded at the distance along the pipe at which it occurs.
NOTE 1
Zero percent inclination is horizontal. 100 percent inclination is 45 degrees from the horizontal. A pipe
sloping downhill when looking in a downstream direction has a negative gradient. A pipe sloping uphill
when looking in a downstream direction has a positive gradient.
NOTE 2
Maximum pipe gradient is the steepest positive (uphill) gradient or the shallowest negative (downhill)
gradient, looking in a downstream direction. Minimum pipe gradient is the steepest negative (downhill)
gradient or the shallowest positive (uphill) gradient, looking in a downstream direction.
9.19.1
The survey data may also be provided packaged with any proprietary software viewer necessary to
view all of the data in accordance with the following:
1) graphical plot showing schematically the invert level determined from the inclinometer survey with:
a) the data fitted to the measured invert levels in the chambers at each end of the pipe run; and,
b) a switchable overlay of camera inclination, plotted against a vertical axis scale of camera
inclination in percent;
2) facilities that allow the inclinometer survey data to be viewed in conjunction with, and linked to, the
CCTV video and photographs, and the coded observations; and,
3) an unrestricted licence for the use of the software viewer.
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10.
10. Chambers defect and geometric survey by laser...
Chambers defect and geometric survey by laser scanner
Survey requirements
Scope of survey
10.1
A chambers defect and geometric survey shall be carried out to determine the inventory, condition,
detailed defects and internal geometry of chambers, including the use of a laser scanner with inbuilt
panoramic still camera(s) and a closed-circuit television (CCTV) camera.
10.2
A chambers defect and geometric survey by laser scanner shall include the following:
1) details of the location, date, equipment and personnel of the survey;
2) details of any pre-cleansing or other associated works carried out;
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3) survey of the required chambers;
4) survey of the location of all chambers and the levels of chamber covers, chamber inverts and the
inverts of pipework connections;
5) identification of the asset type of all surveyed assets in accordance with the classification system
detailed in CD 535 [Ref 5.N];
6) recording of all the mandatory and optional data fields for asset inventory, structural condition
defects, service condition defects, and survey parameters using the codes detailed by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] for all chambers surveyed, and the
merging of these observations into the coded data for any other drainage surveys carried out at the
same time and any other round-tripped, unchanged survey data;
7) survey of the internal chamber geometry by laser scan;
8) recording of an overall asset level structural and service condition grade;
9) recording of an in-chamber video showing the nature of the chamber and the defects recorded;
10) recording of a panoramic 360 degrees composite still photograph of the chamber wall;
11) recording of still photographs showing the typical chamber nature and specific defects; and,
12) submission of a digital report and digital data sets in the formats defined by the Overseeing
Organisations in the NAAs to CD 535 [Ref 5.N] and as detailed in the reporting requirements below.
NOTE
A chambers defect and geometric survey by laser scanner is:
1) a field survey carried out where full and detailed knowledge of the condition and defects of
chambers is needed;
2) carried out where continuous measurement of the internal geometry of the chamber is required; and,
3) applicable in all forms of chamber up to 3m in diameter and up to 10m in depth where the chamber
is substantially dry.
Survey data round-tripping
10.3
Survey data shall be round-tripped from the DDMS where available.
10.4
Where there is some drainage inventory information in the catchment(s) to be surveyed on the DDMS
the survey shall round-trip this data in accordance with specific procedures and formats detailed by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] by:
1) downloading the available information;
2) confirming or updating the inventory, condition and defects of the required chambers in the field;
3) retaining as part of the data, without change, any inventory and condition information on any
non-surveyed chambers and other drainage assets; and,
4) the submission for uploading of this information to the DDMS.
10.5
Where there is no drainage inventory information in the catchment(s) to be surveyed on the DDMS the
survey shall consist of the following:
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1) a first-time survey of the inventory, condition and defects of the required chambers; and,
2) the submission for upload of this information to the DDMS in accordance with specific procedures
and formats detailed by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
NOTE
Additional activities required to complete the round-tripping of drainage information to the DDMS are
provided in the NAAs to CD 535 [Ref 5.N].
Survey equipment
10.6
The laser scanner shall be capable of surveying chambers up to 3m in diameter and up to 10m in depth.
10.7
The laser scanner shall be:
1) independently deployed from the surface without requiring man entry to the chamber;
2) equipped with integral lighting;
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3) equipped with a downward facing solid state, colour CCTV;
a) with a resolution of at least 1.2 megapixels; and,
b) capable of producing a clear, accurate and in-focus record of the internal condition of the
chamber from 150 mm in front of the camera to infinity;
4) equipped with a single or multiple solid-state, colour cameras;
a) producing a panoramic 360 degrees composite image of 100% of the interior chamber wall;
b) each camera with a resolution of at least 1.2 megapixels; and,
c) capable of producing a clear, accurate and in-focus record of the internal condition of the
chamber sidewall from 150 mm in front of the camera to 3m;
5) equipped with a single or multiple laser sources;
a) producing a point cloud on the internal circumference of the chamber with a density of at least
200,000 points per square metre; and,
b) capable of recording the chamber internal geometry to a relative accuracy of +/-5 mm;
6) rated for protection against ingress of solid particles and liquids to IP67;
7) equipped with a means of determining the relative depth of any point on the composite image and
scan to an accuracy of +/-5 mm;
8) equipped with a means of determining the orientation of the image and scan with respect to grid
North to +/-5 degrees to the national survey grid stated by the Overseeing Organisations in the
NAAs to CD 535 [Ref 5.N];
9) equipped with a means of determining the three dimensional coordinates of any point on the scan to
the absolute accuracy stated in CD 535 [Ref 5.N] for detailed survey and to the national survey grid
and national survey datum stated by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N];
10) equipped with a means to correct for any torsional and pendular motion of the scanning head to
allow automatic alignment of adjacent images and scans; and,
11) positioned as close to the vertical axis of the chamber as the location of the cover opening permits.
10.8
The laser scanner control, recording and visualisation software shall be capable of the following:
1) digitally recording a video of the CCTV image;
2) digitally creating and recording an unwrapped panoramic photograph of the chamber wall;
3) digitally recording still photographs of selected features;
4) digitally recording the laser scan of the chamber wall;
5) recording an interpretation of the inventory and condition of the pipework using the codes detailed
by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N];
6) linking the recorded video, panoramic photograph, still photographs and laser scan to each other
and to the coded data; and,
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7) allowing the user to pan, tilt and zoom around the chamber with a virtual camera, add annotations to
images and measure features.
10.9
Topographic survey equipment shall be provided to measure locations and levels to the accuracy
stated in CD 535 [Ref 5.N] for detailed survey and to the national survey grid and national survey datum
stated by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
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Method of survey
10.10
All chamber covers shall be removed and replaced to gain access for the survey.
10.10.1
Access to chambers with bolted covers should be attempted. This may require bolts to be removed
prior to the survey and securely replaced immediately on completion of the survey.
10.11
A reference point shall be marked on the chamber cover frame at the grid north point, and the location
and level surveyed to the accuracy stated in CD 535 [Ref 5.N] for detailed survey and to the national
survey grid and national survey datum stated by the Overseeing Organisations in the NAAs to CD 535
[Ref 5.N].
10.12
All subsequent surveying of the chamber for level, location and north point shall be related to the
reference point marked on the chamber cover frame such that the following can be determined:
1) cover level to national survey datum;
2) chamber invert level to national survey datum;
3) invert level of all incoming and outgoing pipework to national survey datum; and,
4) absolute location of all internal chamber geometry related to national survey datum and national
survey grid.
10.13
Pre-cleansing of the chamber shall be carried out where necessary to complete the survey.
10.14
The depths and nature of any material removed by pre-cleansing shall be recorded and reported.
10.15
The inventory and condition of all required chambers shall be surveyed by CCTV and panoramic
camera and reported by recording all of the mandatory and optional data fields for asset inventory,
structural condition defects, service condition defects, and survey parameters using the codes detailed
by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
10.16
The maximum speed of descent of the laser scanner head shall be 35 mm/s.
10.17
The internal geometry of the chamber shall be surveyed by laser scanner descending the chamber at a
constant speed and related via the reference point marked on the chamber cover frame to the national
survey grid and national survey datum stated by the Overseeing Organisations in the NAAs to CD 535
[Ref 5.N].
10.18
Still photographs shall be taken of each chamber as follows:
1) general location photograph of the chamber prior to removal of the cover showing the marked
reference point;
2) vertical photograph looking down the chamber with cover removed, prior to any cleaning;
3) vertical photograph looking down the chamber with cover removed, following any cleaning;
4) at every incoming and outgoing pipework connection;
5) at any structural or service defect that would lead to the overall grading of the chamber being 3, 4 or
5;
6) orientation of photographs to be recorded along with direction of flow;
7) photographs 1) to 3) above to be recorded as "general photograph" observations;
8) at abandonment; and,
9) all photographs to be recorded in the coded data.
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Interruption of survey
10.19
Interruptions to the survey shall be defined and managed in accordance with the requirements for
pipework and chambers defect survey by CCTV (reading chamber for pipework).
Abandonment of survey
10.20
Abandonment of the survey shall be defined and managed in accordance with the requirements for
pipework and chambers defect survey by CCTV (reading chamber for pipework).
Quality control requirements
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Surveyor competency
10.21
Evidence shall be provided that the surveyor undertaking the laser scanning survey has received
training in the use of the equipment.
10.22
Evidence shall be provided that the surveyor undertaking the survey coding holds an appropriate
qualification in the interpretation of CCTV images of chambers and in defect coding and classification.
10.23
Evidence shall be provided that the surveyor undertaking the location and level topographic survey
holds an appropriate qualification in topographic surveying.
10.24
A quality control system approved by the Overseeing Organisation's representative shall be maintained
and operated to control the accuracy of the defect coding interpretation and reporting in accordance
with the requirements for pipework and chambers defect survey by CCTV.
10.25
Any survey reports failing the coding accuracy shall be recoded by another qualified surveyor and
resubmitted as a replacement for the failed survey.
Survey method quality control
10.26
A method statement shall be provided and approved prior to the commencement of the works that
includes the following:
1) a statement of full compliance with this document or a clear list of any qualifications or
non-compliance of either equipment or procedures, and a full method statement of any alternatives
proposed;
2) the type and version of the laser scanner survey software;
3) any sub-contractors that are to be used and a description of their role.
10.27
Evidence shall be provided that the laser scanner has been serviced and calibrated by the equipment
supplier not more than 12 months prior to the commencement of the survey works.
Reporting requirements
Data submission
10.28
The survey report shall consist of the following digital data split into drainage catchments suitable for
upload to the DDMS:
1) coded survey data in the digital format(s) defined by the Overseeing Organisations in the NAAs to
CD 535 [Ref 5.N] merging together coded survey data from:
a) the surveys of all chambers in the catchment;
b) any other drainage surveys carried out in the catchment at the same time; and,
c) any round-tripped, unchanged survey data in the catchment;
2) video recordings referenced in the coded survey data, as detailed below;
3) photographs of selected features referenced in the coded survey data, as detailed below;
4) unwrapped panoramic photograph of the walls of each chamber, as detailed below;
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5) CAD drawing files, as detailed below.
10.28.1
A summary report in PDF format may additionally be provided, including the following:
1) a description of the survey carried out, its location, and the equipment and methods used;
2) details of the quality control procedures;
3) a schematic drawing of each chamber in plan and section showing the position, references and
invert levels of all incoming and outgoing pipes, the level of any water and/or silt, the position and
nature of any defects and the overall structural and service grade of the chamber;
4) details of the coded defects for each asset surveyed in tabular format;
5) a summary table of all chambers surveyed detailing the asset reference, asset type, cover level,
invert level, the overall structural and service grade;
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6) a summary table of abandoned chamber surveys detailing the chamber asset reference and reason
for abandonment; and,
7) a summary table of any pre-cleansing carried out detailing the chamber asset reference, the method
of cleansing, the nature of removed material and the outcome.
Survey data
10.29
All survey data shall be reported using the standard coding system and nomenclature defined by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
10.30
All coding shall be directly entered into a computer or handheld device that restricts entries to valid
codes.
10.31
All coded survey data shall be reported merged with the coded data from any other forms of drainage
survey carried out in the catchment at the same time together with any unchanged round-tripped
survey data.
10.32
Where the survey is round-tripping existing drainage data from the DDMS the unique reference of each
asset shall be retained in the round-tripped data.
10.33
Where new assets are added to the data during the survey they shall be assigned a field reference that
is unique within the survey.
NOTE
A permanent unique asset reference will be automatically assigned by the DDMS when the data is
uploaded.
10.34
At the commencement of the survey of every chamber new header information in accordance with the
requirements of the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] shall be completed.
10.35
Where different observation types occur at the same point each shall be coded separately.
10.36
Where a continuous observation changes in nature along its length, it shall be split into separately
coded observations at each change.
10.37
Each of the defects recorded shall be scored in accordance with the scoring system detailed by the
Overseeing Organisations in the NAAs to CD 535 [Ref 5.N] for all chambers surveyed.
10.37.1
Automated condition scoring should be carried out by the recording software or by the DDMS during
data upload.
10.38
The overall asset level structural and service condition grade shall be derived by aggregating the
scores for each recorded defect in accordance with the aggregating procedure detailed in CD 535 [Ref
5.N] for all chambers surveyed.
10.38.1
Automated aggregation of the scores to determine the overall asset level structural and service
condition grades should be carried out by the recording software or by the DDMS during data upload.
10.39
All recorded survey data shall be submitted for upload to the DDMS in the standard digital format(s)
defined by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
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10.39.1
10. Chambers defect and geometric survey by laser...
The survey data may also be provided packaged with any proprietary software viewer necessary to
view all of the data in accordance with the following:
1) all of the coded data (both header and detailed defect observations) for every inspection carried out
on every chamber;
2) all of the associated photographs, panoramic photographs and videos;
3) all of the associated 3D laser scans with facilities to carry out manual measurements from the scan;
4) facilities that allow the survey data to be viewed in conjunction with the video, photographs and 3D
laser scans, such that viewing an asset or observation in the data will automatically retrieve the
associated section of video and relevant photographs; and,
5) an unrestricted licence for the use of the software viewer.
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Video recordings
10.40
All video recordings shall be:
1) in colour;
2) in MPEG format as .MPG files;
3) at a resolution of at least 1.2 megapixels;
4) at a frame rate of at least five frames per second; and,
5) indexed in the coded data.
Photographs
10.41
All photographs taken shall be submitted for upload to the DDMS as documents attached to the
observation to which they relate, or if they are of a general nature, attached to the asset to which they
relate.
10.42
All photographs shall be:
1) in colour;
2) in JPEG format as .JPG files;
3) at a resolution of at least 1.2 megapixels; and,
4) indexed in the coded data.
Unwrapped panoramic photographs
10.43
All unwrapped panoramic photographs shall be submitted for upload to the DDMS as documents
attached to the asset to which they relate.
10.44
All unwrapped panoramic photographs shall be:
1) in colour;
2) in JPEG format as .JPG files;
3) at a horizontal resolution of at least 4,000 pixels for a full circumference;
4) at a vertical resolution that ensures that the image is distortion free; and,
5) indexed in the coded data.
CAD drawing files
10.45
A CAD drawing file of the 3D graphical representation of the internal surface of each surveyed chamber
shall be provided in DWG, DXF and PDF file formats referenced to the national survey grid and
national survey datum stated by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
10.45.1
CAD drawing files in DWG, DXF and PDF formats may additionally be provided, showing the following:
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1) the extent of the completed survey.
2) the location and unique reference number of each drainage asset surveyed;
3) the overall service and structural condition grade of each asset;
4) any errors in any provided drawings or layout data noted during the survey; and,
5) overlaid on available base mapping showing the highway, highway boundary, structures and other
reference features of the surveyed corridor and the national grid.
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10.46
All CAD drawing files shall be produced in accordance to GG 184 [Ref 20.N].
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11.
11. Ditch profile survey
Ditch profile survey
Survey requirements
Scope of survey
11.1
A ditch profile survey shall be carried out to determine the longitudinal and cross-sectional profile of
ditches in association with an all assets condition and connectivity survey, and including the
determination of potential soil contamination.
11.2
A ditch profile survey shall include the following:
1) details of the location, date, equipment and personnel of the survey;
2) survey of the plan location, longitudinal and cross-section profiles of the required ditches; and,
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3) soil sampling and chemical testing of potential spoil arisings.
NOTE
A ditch profile survey is carried out:
1) in association with an all assets condition and connectivity survey;
2) where measurement of the longitudinal and cross-sectional profile of the ditch is required to aid
planning of future cleaning or re-profiling works;
3) where soil contamination testing of potential spoil arisings to aid planning of future cleaning or
re-profiling works is required; and,
4) in all forms of unlined and lined ditches.
Survey data round-tripping
11.3
Survey data shall be round-tripped from the DDMS, where available, in accordance with the
requirements for all assets condition and connectivity survey.
Survey equipment
11.4
Topographic survey equipment shall be provided to measure plan location and level to the accuracy
stated in CD 535 [Ref 5.N] for detailed survey and to the national survey grid and national survey datum
stated by the Overseeing Organisations in the NAAs to CD 535 [Ref 5.N].
11.4.1
A GNSS pole-mounted survey receiver with tilt compensation should be employed to determine
absolute location and level.
NOTE
Where GNSS reception is poor a total station can be employed with absolute location and level
determined by reference to an Ordnance Survey benchmark or temporary benchmark.
11.5
A manual hand auger capable of taking soil samples to 0.5m depth shall be provided.
Method of survey
11.6
The plan location, longitudinal and cross-sectional profile of each ditch shall be surveyed together with
the determination of potential soil contamination.
11.7
A series of cross-sectional ditch profiles shall be taken at longitudinal intervals along the length of the
ditch as follows:
1) at the start of the ditch;
2) at the mid-point along the length of the ditch;
3) at the end of the ditch;
4) at all significant changes in vertical gradient;
5) at all significant changes in plan alignment; and,
6) at intermediate points such that the spacing between profiles is not more than 50 m.
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11.8
11. Ditch profile survey
At each cross-sectional ditch profile a series of levels shall be taken as follows:
1) at the fence line;
2) at the top of the ditch (inside);
3) at the bottom of the ditch channel (inside);
4) at the bottom of the ditch channel (outside);
5) at the top of the ditch (outside);
6) at the crest of the cutting or toe of the embankment;
7) at the back of the verge;
8) at the top of the kerb;
9) at the edge of pavement channel line; and,
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10) at any significant undulations or benches in the ground surface.
11.9
At the location of each cross-section the depth and nature of detritus in the ditch shall be determined as
follows:
1) a CAT scan to check for any buried utilities;
2) in unlined ditches a hand augered hole up to 0.5m deep penetrating not less than 0.1m in to the in
situ soil;
3) in lined ditches a hand augered hole up to 0.5m deep taken to refusal on the lining;
4) a photograph of the flights of the extracted hand auger showing the detritus/soil profile with a tape
measure for scale; and,
5) a description of the detritus/soil profile in accordance with the BSI 'Code of practice for ground
investigations' BS 5930 [Ref 2.N] with specific recording of the presence or absence of any visual or
olfactory indications of contamination.
11.10
At selected cross-sections a sample of the detritus/soil shall be taken from the auger flights where:
1) the detritus/soil is thicker than 50 mm;
2) the sampling frequency along the length of the ditch is in accordance with the requirements for soil
characterisation sampling and testing; and,
3) specifically where there are visual or olfactory indications of contamination.
11.11
Each detritus/soil sample shall be taken, labelled, stored, transported and tested in accordance with the
procedures for soil characterisation sampling and testing.
Interruption of survey
11.12
Interruptions to the survey shall be defined and managed in accordance with the requirements for all
assets condition and connectivity survey.
Abandonment of survey
11.13
Abandonment of the survey shall be defined and managed in accordance with the requirements for all
assets condition and connectivity survey.
Quality control requirements
Surveyor competency
11.14
Evidence shall be provided that the surveyor undertaking the location and level surveying holds an
appropriate qualification in topographic surveying.
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Survey method quality control
11.15
Evidence shall be provided prior to the commencement of the works that the survey equipment has
been calibrated and complies with the locational and level accuracy stated in CD 535 [Ref 5.N] for
detailed surveys.
Reporting requirements
Data submission
11.16
The survey report shall consist of the following digital data split into drainage catchments suitable for
upload to the DDMS:
1) a summary report in PDF format, as detailed in the report requirements;
2) photographs of the hand auger samples as detailed in the photographs requirements; and,
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3) CAD drawing files, as detailed in the CAD drawing file requirements (see clause 11.19).
Report
11.17
A summary survey report shall be provided in PDF format including the following:
1) a description of the survey carried out, its location, and the equipment and methods used;
2) details of the quality control procedures for field survey and laboratory testing; and,
3) reporting of the chemical test results and characterisation in accordance with the procedures for soil
characterisation sampling and testing.
Photographs
11.18
All photographs shall be:
1) in colour;
2) in JPEG format as .jpg files;
3) submitted for upload to the DDMS as documents attached to the asset to which they relate as part of
the all asset condition and connectivity survey deliverable; and,
4) at a resolution of at least 1.0 megapixels.
CAD drawing files
11.19
CAD drawing files in DWG, DXF and PDF formats shall be provided showing the following:
1) the extent of the completed survey;
2) the location and unique DDMS reference number of each drainage asset surveyed;
3) a plan of each ditch with the location and unique reference number of each cross-sectional profile;
4) a series of cross-sectional profiles cross-referenced to the locational plan;
5) the overall service and structural condition grade of each asset;
6) any errors in any provided drawings or layout data noted during the survey;
7) overlaid on available base mapping showing the highway, highway boundary, structures and other
reference features of the surveyed corridor and the national grid.
11.20
All CAD drawing files shall be produced in accordance to GG 184 [Ref 20.N].
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12.
12. Soil characterisation sampling and testing
Soil characterisation sampling and testing
Sampling and testing requirements
Scope of sampling and testing
12.1
Soil characterisation sampling and testing shall be carried out in association with a drainage survey to
determine whether the spoil arising from potential drainage works should be characterised as
hazardous or non-hazardous for the purposes of off-site disposal.
12.2
Soil characterisation sampling and testing shall include the following:
1) pre-sitework study to determine the potential contaminants to be investigated;
2) details of the location, date, method and personnel carrying out the sampling;
3) assessment of the sampling frequency required;
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4) taking of soil samples;
5) transport of samples to the laboratory;
6) details of the laboratory carrying out the chemical testing;
7) assessment of the chemical tests required;
8) carrying out of chemical testing;
9) characterisation of the hazardous or non-hazardous nature of each sample;
10) assigning of waste list codes to each drainage asset; and,
11) reporting of the test results and characterisation.
NOTE 1
The overall process is summarised in Figure 12.2N1
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Figure 12.2N1 Summary of soil characterisation process
NOTE 2
Characterisation is carried out in accordance with Technical Guidance WM3 [Ref 23.N] as detailed
below.
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NOTE 3
12. Soil characterisation sampling and testing
Soil characterisation sampling and testing is carried out:
1) in association with surveying the inventory and condition of the drainage assets;
2) where future drainage works will generate spoil arisings that need to be disposed of off-site;
3) to determine whether the spoil arisings will be characterised as hazardous or non-hazardous for the
purposes of off-site disposal.
NOTE 4
Soil characterisation sampling and testing is not suitable for:
1) determining whether spoil arisings can be reused on site (see Waste CoP [Ref 3.N]);
2) waste acceptance criteria (WAC) testing to determine the method of disposal (see EPG [Ref 7.N]);
nor,
3) assessment of asbestos in highway assets (see GG 105 [Ref 1.N])
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NOTE 5
Additional stages of sampling, testing and assessment will be required as part of the remedial or
maintenance works on the drainage asset if the material is to be disposed of off-site, including WAC
testing to determine the method of disposal.
Pre-sitework study
12.3
The specific drainage assets to be sampled and tested on each site shall be detailed in the task order.
12.4
A site-specific study shall be carried out to assign the source of the run-off into the drainage asset to be
sampled into one, or more, of the following categories:
1) run-off from the highway;
2) run-off from adjacent farmland;
3) run-off from adjacent residential area; or,
4) run-off from adjacent commercial or industrial area, or former industrial area.
12.4.1
A site-specific study may include:
1) completion of a desk study;
2) carrying out a pre-survey site walkover;
3) consulting spillage or incident records;
4) consulting maintenance records; and/or,
5) discussions with maintenance personnel.
12.4.2
The site-specific study should identify any particular chemical contaminants that may be present due to,
for example, historic accidental spills in the vicinity or run-off from an adjacent industrial site.
12.4.3
The site specific study should record any constraints on site access and determine the access
arrangements for the survey works.
Sampling
12.5
Sampling frequency shall be compliant with Landfill [Ref 4.N] "Dispose of waste to landfill" as
summarised in Table 12.5.
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Table 12.5 Sampling frequency
Estimated mass
of spoil
arisings
Drainage
asset size
Drainage asset type
Point e.g. chamber
Less than 100
tonne
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More than 100
tonne
Sampling
requirements
Any
2 samples
Less than 50
m length
2 samples
Greater than
50m length
5 samples
Region e.g. pond
Any
5 samples
Any
Any
As per Landfill
[Ref 4.N]
Continuous e.g. ditch,
channel, filter drain
Assumptions
Assumes
homogeneous
arisings
Assumes
heterogeneous
arisings
12.6
Sampling locations shall be selected to be representative of the estimated volume of spoil arisings and
specifically include areas suspected of being contaminated based on visual or olfactory evidence, or
the site-specific study.
12.6.1
Where the number of samples taken from a drainage asset is greater than the number required for
testing, samples should be selected to be representative of areas of greater thickness of material or
where visible or olfactory evidence of contamination has been identified.
12.7
Samples shall be taken, labelled, stored and transported with chain of custody procedures in
accordance with the investigation code of practice BS 10175 [Ref 13.N].
12.8
All samples shall be delivered to the laboratory:
1) within the time limits appropriate to the chemical determinands to be tested;
2) pre-treated on site if required by the test method; and,
3) transported in cooled containers.
NOTE
Some chemical analyses, particularly for volatile organics, need to be completed within a defined
period of time in order to avoid the samples being classified as deviating from standard procedures.
Some samples need to be pre-treated with stabilising chemicals on site. Samples are transported in
cool boxes to preserve their chemistry. The chemical testing laboratory will be able to provide the
specific requirements appropriate to their methods of test.
Testing
12.9
The suites of chemical testing indicated in Table 12.10a and detailed in Table 12.10b shall be carried
out on each sample dependent on the run-off category of the drainage asset.
12.10
Where the run-off into a drainage asset arises from multiple sources the most onerous suites of
chemical testing shall be carried out.
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Table 12.10a Chemical test suites for each run-off category
Test suites
Inorganic
Organic
Highway
x
x
Farmland
x
x
Residential
x
x
Commercial or
industrial
x
x
Run-off category
Asbestos
Agricultural pollutants
Industrial pollutants
x
x
x
x
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Table 12.10b Definition of chemical test suites
Chemical determinands (units)
Test suite
Inorganic
Total arsenic (mg/kg), total cadmium (mg/kg), total copper (mg/kg), total
lead (mg/kg), total mercury (mg/kg), total nickel (mg/kg), total selenium
(mg/kg), total zinc (mg/kg), trivalent chromium (mg/kg), hexavalent
chromium (mg/kg), pH, moisture content (%)
Organic
Speciated poly aromatic hydrocarbons (PAH) (EPA16) (mg/kg), total
petroleum hydrocarbons (TPH) (mg/kg)
Asbestos
Asbestos (%)
Agricultural pollutants
DDT (1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane) (mg/kg), chlordane
(mg/kg), hexachlorocyclohexanes (including lindane) (mg/kg), dieldrin
(mg/kg), endrin (mg/kg), heptachlor (mg/kg), hexaclorobenzene (mg/kg),
chlordecone (mg/kg), aldrin (mg/kg), atrazine (mg/kg), mirex (mg/kg),
toxaphene (mg/kg), pentachlorobenzene (mg/kg), endosulfan (mg/kg)
Industrial pollutants
Pentachlorobenzene (mg/kg), polychlorinated dibenzo-p-dioxins and
dibenzofurans (PCDD/PCDF) (µg/kg), hexabromobiphenyl (mg/kg),
polychlorinated biphenyls (PCBs) (mg/kg), TPH (C5-C10, C10-C25, C25-C
40) (mg/kg), benzene/toluene/ethylbenzene/xylene (BTEX) (mg/kg), methyl
tert-butyl ether (MTBE) (mg/kg), total cyanide (mg/kg)
12.11
Additional chemical determinands shall be included where the site-specific study has indicated the
presence or potential presence of specific contaminants not included within the test suites.
12.12
The test method and the limits of detection for each chemical determinand shall be capable of
determining whether the material is hazardous or non-hazardous utilising the procedures defined in
Technical Guidance WM3 [Ref 23.N].
12.13
Each sample shall be described in accordance with BS 5930 [Ref 2.N].
Quality control requirements
Field sampling competency
12.14
Evidence shall be provided that the surveyor or technician taking the samples has received training in
the taking, labelling, storage and transportation chain of custody procedures for contaminated soil
samples in accordance with BS 10175 [Ref 13.N], and sample description in accordance with BS 5930
[Ref 2.N].
Laboratory competency
12.15
Evidence shall be provided that the chemical testing laboratory is accredited by the United Kingdom
Accreditation Service (UKAS) to the current version of BS EN ISO/IEC 17025 [Ref 9.N] for compliance
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with MCERTS [Ref 18.N] for undertaking chemical testing of soil samples on the specific determinands
required by this standard.
Characterisation
12.16
Each sample shall be characterised as either hazardous or non-hazardous in accordance with
Technical Guidance WM3 [Ref 23.N].
NOTE 1
The www.hazwasteonline.com software tool can be utilised to carry out the sample characterisation.
NOTE 2
For samples containing asbestos the sample is characterised as hazardous in accordance with
Technical Guidance WM3 [Ref 23.N] if there is either:
1) > 0.1 % by weight of asbestos fibres in the overall sample that are free and dispersed; or,
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2) one or more pieces of visible asbestos containing materials are present where the asbestos content
within those pieces is > 0.1 % by weight.
12.17
All soil sample characterisations from a given drainage asset shall be reviewed and an overall waste
code assigned to the spoil arisings in accordance with the list of wastes in Technical Guidance WM3
[Ref 23.N] and the procedure summarised in Figure 12.2N1.
NOTE
The most likely Technical Guidance WM3 [Ref 23.N] list of waste codes for drainage arisings are given
in Table 12.17N.
Table 12.17N Example list of waste codes for drainage arisings
List of waste description
Waste status
Waste code
Soil and stones containing hazardous substances
Hazardous
17 05 03
Soil and stones other than those mentioned in 17 05 03
Non-hazardous
17 05 04
Dredging spoil containing hazardous substances
Hazardous
17 05 05
Dredging spoil other than those mentioned in 17 05 05
Non-hazardous
17 05 06
Insulation materials containing asbestos
Hazardous
17 06 01
Construction materials containing asbestos
Hazardous
17 06 05
Reporting requirements
Data submission
12.18
The report shall consist of a submission for upload to the DDMS of the following digital data:
1) a report in PDF format as detailed in the report requirements; and,
2) laboratory test results as an electronic data file in the current version of the AGS4.1 [Ref 6.N] data
transfer format, with all the chemical test results required in tabular format in the PDF report.
Report
12.19
A report shall be provided in PDF format presenting the following:
1) details of the location, date, method and personnel carrying out the sampling and the laboratory
carrying out the chemical testing;
2) a description of the sampling and testing carried out, its location, and the equipment and methods
used, including:
a) chemical test procedures; and,
b) limits of detection for each test.
3) details of the quality control procedures, including chain of custody records; and,
4) tabulated chemical test results and characterisation including:
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a) site reference;
b) DDMS unique drainage asset reference if the asset already exists on the DDMS;
c) suppliers asset reference that is unique within the survey;
d) drainage asset type;
e) the specific location within the asset from which the sample was taken, cross-referenced to the
associated drainage survey;
f) sample number;
g) laboratory reference number (if different from the sample number);
h) chemical test results for each determinand on each sample;
i) units of measure for each determinand;
j) BS 5930 [Ref 2.N] soil description of each sample;
k) date of sampling;
l) date of testing;
m) Technical Guidance WM3 [Ref 23.N] characterisation of each sample;
n) any notes or comments related to the characterisation of specific samples;
o) Technical Guidance WM3 [Ref 23.N] list of waste code for each asset; and,
p) any notes or comments related to the assessment of the list of waste code for specific assets.
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13.
13. All assets defect survey
All assets defect survey
Survey requirements
Scope of survey
13.1
An all assets defect survey shall be carried out to determine the inventory, condition and detailed
defects of pipework and the associated chambers and gullies and the inventory, asset level condition
and connectivity of all other drainage assets in a drainage system.
13.2
An all assets defect survey shall include the following:
1) all of the requirements for a pipework and chambers defect survey by CCTV;
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2) all of the requirements for an all assets condition and connectivity survey of all other assets in the
drainage system apart from the pipework and chambers; and,
3) submission of digital data as single survey packages for each catchment that combines the various
aspects of the survey.
13.2.1
An all assets defect survey may include the following optional items:
1) all of the requirements for a filter drain condition survey by GPR;
2) all of the requirements for a pipework geometric survey by laser profiler;
3) all of the requirements for a pipework inclination survey;
4) all of the requirements for a chambers defect and geometric survey by laser scanner;
5) all of the requirements for a ditch profile survey; and/or,
6) all of the requirements for soil characterisation sampling and testing.
NOTE
An all assets defect survey is:
1) a field survey carried out where full and detailed knowledge of the condition and defects of the below
ground pipework is needed;
2) combined with a desk study and quick walkover survey of the remainder of the drainage system;
3) optionally combined with other types of survey to gain additional information on particular aspects of
the drainage system; and,
4) all reported as single data packages for each catchment, with an overall summary report in PDF
format.
Survey data round-tripping
13.3
Survey data shall be round-tripped from the DDMS, where available, in accordance with the
requirements for pipework and chambers defect survey by CCTV but applied to all drainage assets in
the catchment(s) to be surveyed.
Desk study
13.4
A desk study shall be carried out in accordance with the requirements for all assets condition and
connectivity survey.
13.4.1
The desk study may include the requirements for soil characterisation sampling and testing.
Survey equipment
13.5
The survey equipment shall be as detailed in the requirements for:
1) pipework and chambers defect survey by CCTV;
2) all assets condition and connectivity survey of all other assets in the drainage system apart from the
pipework and chambers.
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Method of survey
13.6
The method of survey shall be as detailed in the requirements for:
1) pipework and chambers defect survey by CCTV;
2) all assets condition and connectivity survey of all other assets in the drainage system apart from the
pipework and chambers.
Interruption of survey
13.7
Interruptions to the survey shall be defined and managed in accordance with the requirements for
pipework and chambers defect survey by CCTV.
Abandonment of survey
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13.8
Abandonment of the survey shall be defined and managed in accordance with the requirements for
pipework and chambers defect survey by CCTV.
Quality control requirements
Surveyor competency
13.9
Evidence shall be provided that the surveyor/surveyors undertaking the survey has/have received
training in the use of the equipment and the interpretation of the results in accordance with the
requirements for:
1) pipework and chambers defect survey by CCTV;
2) all assets condition and connectivity survey of all other assets in the drainage system apart from the
pipework and chambers; and,
3) any other survey method detailed in the task order.
Survey method quality control
13.10
Survey method quality control procedures shall be carried out in accordance with the requirements for:
1) pipework and chambers defect survey by CCTV;
2) all assets condition and connectivity survey of all other assets in the drainage system apart from the
pipework and chambers; and,
3) any other survey method detailed in the task order.
Reporting requirements
Data submission
13.11
The survey report shall consist of the following digital data split into drainage catchments suitable for
upload to the DDMS:
1) coded survey data in the digital format(s) defined by the Overseeing Organisations in the NAAs to
CD 535 [Ref 5.N], as detailed in the survey data requirements;
2) video recordings referenced in the coded survey data, as detailed in the video recordings
requirements;
3) photographs referenced in the coded survey data, as detailed in the photographs requirements;
4) a report in PDF format, as detailed in the report requirements; and,
5) CAD drawing files, as detailed in the CAD drawing file requirements.
Survey data
13.12
All survey data shall be reported in accordance with the requirements for:
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CS 551 Version 1.0.0
13. All assets defect survey
1) pipework and chambers defect survey by CCTV;
2) all assets condition and connectivity survey of all other assets in the drainage system apart from the
pipework and chambers; and,
3) any other survey method detailed in the task order.
13.13
The survey data shall be provided as a single survey package for each catchment that combines the
various aspects of the survey.
Video recordings
13.14
All video recordings shall be reported in accordance with the requirements for:
1) pipework and chambers defect survey by CCTV; and,
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2) any other survey method detailed in the task order that produces video output.
Photographs
13.15
All photographs shall be reported in accordance with the requirements for:
1) pipework and chambers defect survey by CCTV;
2) all assets condition and connectivity survey of all other assets in the drainage system apart from the
pipework and chambers; and,
3) any other survey method detailed in the task order.
Report
13.16
The summary report shall be provided as a single PDF detailing the results for each catchment that
combines the various aspects of the survey.
13.16.1
A summary report in PDF format may be provided in accordance with the requirements for:
1) pipework and chambers defect survey by CCTV; and,
2) any other survey method detailed in the task order.
CAD drawing files
13.17
All CAD drawing files shall be produced in accordance to GG 184 [Ref 20.N].
13.17.1
CAD drawing files may be provided in accordance with the requirements for:
1) pipework and chambers defect survey by CCTV; and,
2) any other survey method detailed in the task order.
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CS 551 Version 1.0.0
14.
14. Normative references
Normative references
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The following documents, in whole or in part, are normative references for this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
Ref 1.N
Highways England. GG 105, 'Asbestos management'
Ref 2.N
BSI. BS 5930, 'Code of practice for ground investigations'
Ref 3.N
CL:AIRE. Waste CoP, 'Definition of Waste Code of Practice.'
Ref 4.N
www.gov.uk/guidance/dispose-of-waste-to-landfill. Environment Agency. Landfill,
'Dispose of waste to landfill'
Ref 5.N
National Highways. CD 535, 'Drainage asset data and risk management'
Ref 6.N
Association of Geotechnical and Geoenvironmental Specialists. AGS4.1, 'Electronic
transfer of geotechnical data'
Ref 7.N
DEFRA. EPG, 'Environmental Permitting Guidance. The Landfill Directive.'
Ref 8.N
BSI. British Standards Institution. BS 8599-2, 'First aid kits. Specification for the
contents of motor vehicle first aid kits.'
Ref 9.N
ISO. BS EN ISO/IEC 17025, 'General requirements for the competence of testing and
calibration laboratories'
Ref 10.N
SI 2015 No.51 (CDM Regs), 'HEALTH AND SAFETY - The Construction (Design and
Management) Regulations 2015' , 2015
Ref 11.N
The National Archives. legislation.gov.uk. SI 1997/1713, 'HEALTH AND SAFETY.
The Confined Spaces Regulations 1997'
Ref 12.N
National Highways. GG 101, 'Introduction to the Design Manual for Roads and
Bridges'
Ref 13.N
BSI . British Standards Institution. BS 10175, 'Investigation of potentially
contaminated sites. Code of practice'
Ref 14.N
HSE. HSE L153, 'Managing health and safety in construction: Construction (Design
and Management) Regulations 2015. Guidance on Regulations'
Ref 15.N
Highways England. MCHW Series 0500, 'Manual of Contract Documents for Highway
Works, Volume 1 Specification for Highway Works. Series 500 Drainage and service
ducts.'
Ref 16.N
Highways England. MCHW Series 0100, 'Manual of Contract Documents for Highway
Works. Volume 1 - Specification for Highway Works. Series 100 - Preliminaries '
Ref 17.N
WRc. MSCC5 2013, 'Manual of Sewer Condition Classification 5th Edition'
Ref 18.N
Environment Agency. 2018. MCERTS, 'Performance standard for laboratories
undertaking chemical testing of soils.'
Ref 19.N
Highways England. GG 104, 'Requirements for safety risk assessment'
Ref 20.N
Highways England. GG 184, 'Specification for the use of Computer Aided Design'
Ref 21.N
SI 1996/1592, 'The Construction (Health, Safety and Welfare) Regulations'
Ref 22.N
SI 2016/1107, 'The Equipment and Protective Systems Intended for Use in Potentially
Explosive Atmospheres Regulations 2016 '
Ref 23.N
Environment Agency, Natural Resources Wales, Scottish Environment Protection
Agency and Northern Ireland Environment Agency, 2018. Technical Guidance WM3,
'Waste Classification: Guidance on the classification and assessment of waste'
78
CS 551 Version 1.0.0
15.
15. Informative references
Informative references
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
The following documents are informative references for this document and provide supporting
information.
Ref 1.I
The National Archives. legislation.gov.uk. SI 2002/2776, 'Health and Safety: The
Dangerous Substances and Explosive Atmospheres Regulations 2002'
Ref 2.I
American Society for Testing and Materials. ASTM F1216-16, 'Standard Practice for
Rehabilitation of Existing Pipelines and Conduits by the Inversion and Curing of a
Resin-Impregnated Tube'
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CS 551 Version 1.0.0
Appendix A. Drainage condition grade quick assessment
Appendix A. Drainage condition grade quick assessment
A1
Introduction
This procedure provides a quick method of assessing the overall condition grade of highway drainage
assets without undertaking a detailed defect-level survey. It can be used for most drainage asset types,
both above and below ground, and is intended for use with the following:
1) all assets condition and connectivity survey;
2) priority asset survey;
3) filter drain condition assessment by GPR (structural condition only); and,
4) any other form of quick asset survey or inspection where a measure of current condition is required.
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A2
Structural and service condition
Each drainage asset is visually assessed for both structural and service condition and a whole number
grade from 1 to 5 is assigned to each. In certain cases a grade of 9 or 0 may be assigned. The grades
are defined in CD 535 [Ref 5.N].
Where there are several defects of different types or severity in an asset, the most severe defect
determines the structural or service grade.
Where the inspection of an asset has been attempted, but it was not possible to assess the condition
(for example due to the asset being buried or otherwise obscured), a grade of 9 is assigned. Where it
has only been possible to inspect part of an asset, the grades reflect those parts that have been seen.
Where the unseen part could not be inspected because, for example, the pipe was blocked or the ditch
was severely overgrown with vegetation, then these defects are taken into account in assessing the
overall asset grades.
A grade of 0 is equivalent to no grade, indicating that assessment of the asset's condition has not been
attempted, for example because recording of that asset's condition is irrelevant (such as for ghost
nodes), or because the previously recorded asset could not be found in the field.
A3
Asset grouping
For the purposes of the quick assessment procedure, the various drainage asset types are grouped
together into assets of similar construction and function, as shown in Table A.1 below. The grouping
generally follows that of CD 535 [Ref 5.N], but with the following additional subdivisions:
1) chambers are split into chambers and gullies;
2) ditches and channels are split into four depending on whether their construction is hard or soft and
open or enclosed;
3) inlets and outlets are assessed using different criteria, depending on whether there is a formal
structure, such as a headwall, or not;
4) for combined surface and sub-surface filter drains the condition of the granular backfill medium and
the pipe are assessed separately and the worst grade is then reported for the asset.
The ancillaries group is a mixture of various asset types, some of which may occur either as a
standalone asset, or as an attribute of another asset, for example a flow control device within a
chamber or inlet/outlet. Where it occurs as part of another structure, then the condition grades relate to
the total structure, including the ancillary item. Pumping stations are a special case and require
specialist mechanical and electrical inspections that are beyond the scope of the quick assessment
method, which is limited to a high level assessment of whether there is deterioration of the structure
and whether the pumping station is performing (pumping water).
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Appendix A. Drainage condition grade quick assessment
Table A.1 Grouping of drainage asset types for condition quick assessment
CD 535
[Ref 5.N]
Asset group
Chambers
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Inlets and
outlets
Asset subgroup for condition grade quick
assessment procedure
Included asset types
Chambers
Manhole, catchpit, inspection chamber,
rodding eye, soakaway chamber,
soakaway borehole, bifurcation or storm
overflow, lamphole, other special
chamber
Gullies
Gully, instrumented gully
With formal structure
Outfall, inlet, outlet, grip inlet
Without formal structure
Outfall, inlet, outlet, grip inlet
Pipework, gravity drain, rising main,
culvert, syphon
Pipes
Combined surface and sub-surface filter
drain (pipe)
Combined surface and sub-surface filter
drain (filter media)
Filter drains
Counterfort drain, filter drain, soakaway
trench
Ditches and
channels
A4
Ditches
Ditch, grip
Enclosed channels
Combined kerb and drainage channel,
combined pipe and channel drain, linear
drainage channel
Open channels
Surface water channel, drainage channel
block, edge channel
Grassed channels
Grassed surface water channel or swale
Ponds
Detention basin, retention pond, sediment
pond, infiltration basin, pollution
containment pond or tank, wetlands, reed
bed treatment system, pond
(undifferentiated)
Ancillaries
Standalone flow control device,
interceptor, oil separator, pumping station
(overall structure and function), vortex
separator
Excluded assets
The drainage condition grade quick assessment method is not applicable to the asset types listed in
Table A.2 below, for one of the following reasons, and both structural and service grade of 0 should be
assigned:
1) the nature of the asset cannot be assessed without potentially destructive internal investigations;
2) specialist mechanical and electrical survey is required; or,
3) the asset type does not represent a physical asset.
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Appendix A. Drainage condition grade quick assessment
Table A.2 Drainage asset types excluded from condition quick assessment
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CD 535 [Ref 5.N]
Asset group
Excluded asset types
Pipes
Land drainage
Requires potentially
destructive internal
investigations
Filter drains
Fin drain, narrow filter drain
Requires potentially
destructive internal
investigations
Ditches and channels
"Over the edge" drainage
No physical asset
Linear cellular storage system, reservoir pavement
Requires potentially
destructive internal
investigations
Pumping station (mechanical and electrical aspects)
Requires specialist
survey
Ghost node, phantom node, region node, connector
node, phantom connector, region connector
No physical asset
Ancillaries
Drainage network
modelling
A5
Reason for exclusion
Condition grade quick assessment definitions and examples
The condition grade quick assessment of each asset is, to some degree, subjective and is based on
the experience of the inspector. To assist in standardising the assessments, asset-specific defect
definitions and photographic examples are given below. The examples are not exhaustive so in some
instances engineering judgement may be required to interpret the condition.
A5.1
Chambers
Chambers should be assessed in accordance with Table A.3 for structural condition and in accordance
with Table A.4 for service condition. The presence of manufactured holes in the chamber wall signifies
a soakaway, as could the presence of granular material within the chamber or no evidence of an
outgoing pipe.
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Appendix A. Drainage condition grade quick assessment
Table A.3 Chambers - Structural condition grade quick assessment
Asset types
Structural
grade
Manhole, catchpit, inspection chamber, rodding eye, soakaway chamber,
soakaway borehole, bifurcation or storm overflow, lamphole, other special chamber
Example
Definition
No defects
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1
No defects
Structurally sound, cover frame,
steps/ladder and safety chains where
required.
Any cracking limited to surface cracks.
Superficial defects
2
Superficial
defects
Individual crack.
Rocking cover.
Unpointed joint.
Minor defects
3
Minor defects
Multiple cracks.
Distortion.
Infiltration.
Loose frame.
Spalling of benching.
Unpointed lifting holes.
Major defects
4
Major defects
Multiple fractures.
Broken structure with sections missing.
Broken cover/frame.
Seized cover.
Loose or missing ladder support.
5
Not fit for
purpose or
unsafe
Void formed behind structure.
Complete collapse.
Missing cover/frame.
Loose or missing step/rung.
Loose or missing handrail.
Insecure or missing safety chain.
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Appendix A. Drainage condition grade quick assessment
Table A.4 Chambers - Service condition grade quick assessment
Asset types
Service grade
Manhole, catchpit, inspection chamber, rodding eye, soakaway chamber,
soakaway borehole, bifurcation or storm overflow, lamphole, other special
chamber
Example
Definition
Clear
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1
Clear
Unobstructed pipe/invert.
No sediment.
Superficial deposits with no loss
of performance
2
Superficial deposits with
no loss of performance
Sediment below invert of outgoing
pipe.
For chambers (other than catchpits)
sediment >5% cross-sectional area
(CSA) of pipe.
3
Performance slightly
reduced
Debris in channel invert.
Sediment filling catchpit sump.
For chambers (other than catchpits)
sediment 5-20% CSA of pipe.
No standing water.
Fine root penetration of structure.
4
Performance severely
reduced
For catchpits pipes partially blocked
<50% diameter.
For chambers (other than catchpits)
sediment 20-75% CSA of pipe.
Tap roots.
Soakaway part full of sediment.
Performance slightly reduced
84
Performance severely reduced
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Appendix A. Drainage condition grade quick assessment
Table A.4 Chambers - Service condition grade quick assessment (continued)
Asset types
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5
Blocked or unsafe
condition
A5.2
Manhole, catchpit, inspection chamber, rodding eye, soakaway chamber,
soakaway borehole, bifurcation or storm overflow, lamphole, other special
chamber
For catchpits sediment >50% pipe
diameter.
For chambers (other than catchpits)
sediment >75% CSA of pipe.
Root mass.
Soakaway full of sediment/water.
Oil contamination.
Blocked or unsafe condition
Gullies
Gullies should be assessed in accordance with Table A.5 for structural condition and in accordance
with Table A.6 for service condition.
Table A.5 Gullies - Structural condition grade quick assessment
Asset types
Gully, instrumented gully
Structural grade
Definition
Example
No defects
1
No defects
Intact pot, frame/grating
and brickwork.
Superficial defects
2
Superficial defects
Cracked pot.
Missing mortar/frame
bedding.
Missing stopper.
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Appendix A. Drainage condition grade quick assessment
Table A.5 Gullies - Structural condition grade quick assessment (continued)
Asset types
Gully, instrumented gully
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Minor defects
3
Minor defects
Fractured pot.
Fractured brickwork.
Cracked grating.
Grating >25 mm below
surface.
4
Major defects
Broken or leaking pot.
Broken brickwork or
missing brick.
Missing bar.
Failure of surrounding
pavement.
Grating 75–125 mm from
channel edge.
5
Not fit for purpose
or unsafe
Collapsed pot.
Collapsed, broken or
missing grating.
Broken or missing frame.
Grating bars parallel to
road.
Grating >125 mm from
channel edge.
86
Major defects
CS 551 Version 1.0.0
Appendix A. Drainage condition grade quick assessment
Table A.6 Gullies - Service condition grade quick assessment
Asset types
Service grade
Gully, instrumented gully
Example
Definition
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Clear
1
Clear
Clear pot, sump and grating
waterway.
2
Superficial deposits with
no loss of performance
Some sediment in sump.
Clear waterway water trap
maintained.
Performance slightly reduced
3
Performance slightly
reduced
Sump full of sediment but
water trap maintained.
Waterway partially
obstructed.
Performance severely reduced
4
Performance severely
reduced
Obstruction to flow, or
significant flow bypass.
Sump full of sediment with
blockage of waterway.
Thick layer of oil.
Blocked or unsafe condition
5
Blocked or unsafe
condition
Complete blockage of flow or
flow bypasses grating.
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A5.3
Appendix A. Drainage condition grade quick assessment
Inlets and outlets (with formal structure)
Inlets and outlets (with formal structure) should be assessed in accordance with Table A.7 for structural
condition and in accordance with Table A.8 for service condition.
Table A.7 Inlets and outlets (with formal structure) - Structural condition grade quick
assessment
Asset types
Structural
grade
Outfall, inlet, outlet, grip inlet
Example
Definition
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No defects
1
No defects
Handrail, path and harness eye present
where required for safe access.
No screen or an inclined screen with a
raking area.
Flow control operational where present.
2
Superficial
defects
Cracked mortar joints.
Loose concrete.
Minor defects
3
Minor defects
Cracked brickwork with no differential
movement.
Exposed reinforcement.
Vertical screen to outlet or deformed
screen.
Major defects
4
Major defects
Displaced bagwork or gabions.
Differential settlement.
Fractured structure (concrete or
brickwork).
Broken screen.
Flow control not operational.
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Appendix A. Drainage condition grade quick assessment
Table A.7 Inlets and outlets (with formal structure) - Structural condition grade quick
assessment (continued)
Asset types
Outfall, inlet, outlet, grip inlet
Not fit for purpose or unsafe
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5
Not fit for
purpose or
unsafe
Collapsed structure.
Handrail, path or harness eye absent
where required for safe access.
Screen present but missing handrails.
Vertical screen to inlet.
Table A.8 Inlets and outlets (with formal structure) - Service condition grade quick assessment
Asset types
Outfall, inlet, outlet, grip inlet
Service grade
Definition
Example
Clear
1
Clear
Unobstructed screen/pipe.
Invert above channel bed.
Superficial deposits with no loss of
performance
2
Superficial deposits with
no loss of performance
Light debris on screen.
Pipe unobstructed.
Invert flush with channel
bed.
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Appendix A. Drainage condition grade quick assessment
Table A.8 Inlets and outlets (with formal structure) - Service condition grade quick assessment
(continued)
Asset types
Outfall, inlet, outlet, grip inlet
Performance slightly reduced
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3
Performance slightly
reduced
Debris on screen causing
standing water in pipe.
Sediment depth in channel <
25% pipe diameter.
Performance severely reduced
4
Performance severely
reduced
Partially blocked screen with
obstruction of flow.
Sediment depth in channel 2
5–75% pipe diameter.
Blocked or unsafe condition
5
Blocked or unsafe
condition
A5.4
Flow severely
impeded/surcharges.
Sediment depth in channel >
75% pipe diameter.
Inlets and outlets (without formal structure)
Inlets and outlets (without formal structure) should be assessed in accordance with Table A.9 for
structural condition and in accordance with Table A.10 for service condition.
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Appendix A. Drainage condition grade quick assessment
Table A.9 Inlets and outlets (without formal structure) - Structural condition grade quick
assessment
Asset types
Structural
grade
Outfall, inlet, outlet, grip inlet
Example
Definition
No defects
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1
No defects
Adequate handrail, fence, path and
harness eye present where required for
safe access.
No screen or inclined screen with raking
area.
Superficial defects
2
Superficial
defects
Settlement of piped outlet.
Minor defects
3
Minor defects
Pipe damaged.
Surrounding bank eroded.
Major defects
4
Major defects
Displaced pipes.
Differential pipe settlement.
Collapsing bank.
5
Not fit for
purpose or
unsafe
Collapsed pipe structure.
Loose pipes in channel.
Failure of bank.
Lack of adequate handrail, fence, path
or harness eye where required for safe
access.
Not fit for purpose or unsafe
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Appendix A. Drainage condition grade quick assessment
Table A.10 Inlets and outlets (without formal structure) - Service condition grade quick
assessment
Asset types
Outfall, inlet, outlet, grip inlet
Service grade
Definition
Example
Clear
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1
Clear
Unobstructed screen/pipe.
Invert above channel bed.
Superficial deposits with no loss of
performance
2
Superficial deposits with
no loss of performance
Light debris.
Pipe unobstructed.
Invert flush with channel
bed.
Performance slightly reduced
3
Performance slightly
reduced
Debris causing standing
water in pipe.
Sediment depth in channel <
25% pipe diameter.
Performance severely reduced
4
Performance severely
reduced
Flow obstructed.
Sediment depth in channel 2
5–75% pipe diameter.
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Appendix A. Drainage condition grade quick assessment
Table A.10 Inlets and outlets (without formal structure) - Service condition grade quick
assessment (continued)
Asset types
Outfall, inlet, outlet, grip inlet
Blocked or unsafe condition
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5
Blocked or unsafe
condition
A5.5
Flow severely impeded or
surcharges.
Sediment depth in channel >
75% pipe diameter.
Pipes
Pipes should be assessed in accordance with Table A.11 for structural condition and in accordance
with Table A.12 for service condition. Combined surface and subsurface filter drains are composed of
the granular backfill medium and the pipe; the condition of these two parts should be assessed
separately and the worst grade reported for the asset as a whole.
Table A.11 Pipes - Structural condition grade quick assessment
Asset types
Structural
grade
Pipework, gravity drain, rising main, culvert, syphon, combined surface and
sub-surface filter drain (pipe)
Example
Definition
No defects
1
No defects
Any cracking limited to surface cracks.
Plastic pipe deformation <5%
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Appendix A. Drainage condition grade quick assessment
Table A.11 Pipes - Structural condition grade quick assessment (continued)
Asset types
Pipework, gravity drain, rising main, culvert, syphon, combined surface and
sub-surface filter drain (pipe)
Superficial defects
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2
Superficial
defects
Circumferential or longitudinal crack.
Medium (estimated 1–1.5x pipe
thickness) open or displaced joint.
Slight wear or spalling.
Plastic pipe deformation 5–10%.
Evidence of previous repair.
Minor defects
3
Minor defects
Multiple or spiral cracks.
Circumferential or longitudinal fracture.
Deformation <5% (rigid) or 10–20%
(plastic).
Large (estimated >1.5 x pipe thickness)
open or displaced joint.
Medium wear or spalling (e.g. visible
aggregate).
Puncture on inside wall (twin wall).
Major defects
4
Major defects
Multiple or spiral fractures or broken.
Deformation 5–10% (rigid) or 20–33%
(plastic).
Severe wear or spalling (e.g. missing
aggregate).
Split on inside wall (twin-wall).
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Table A.11 Pipes - Structural condition grade quick assessment (continued)
Asset types
Pipework, gravity drain, rising main, culvert, syphon, combined surface and
sub-surface filter drain (pipe)
5
Not fit for
purpose or
unsafe
Already collapsed or broken with
deformation >10% (rigid) or >33%
(plastic).
Extensive missing fabric.
Split in inner and outer walls (twin-wall).
Reinforcement defective.
Defective connection.
Open joint or hole with visible soil or
void.
Defective repair.
Not fit for purpose or unsafe
Table A.12 Pipes - Service condition grade quick assessment
Asset types
Service grade
Pipework, gravity drain, rising main, culvert, syphon, combined surface
and sub-surface filter drain (pipe)
Example
Definition
Clear
1
Clear
Unobstructed (no impedance to
flow).
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Appendix A. Drainage condition grade quick assessment
Table A.12 Pipes - Service condition grade quick assessment (continued)
Asset types
Pipework, gravity drain, rising main, culvert, syphon, combined surface
and sub-surface filter drain (pipe)
Superficial deposits with no loss
of performance
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2
Superficial deposits with
no loss of performance
Fine roots, deposits or soil
ingress <5% of CSA.
Intruding lateral <5% diameter.
Performance slightly reduced
3
Performance slightly
reduced
Root mass <20% CSA, or
deposits or soil ingress 5–20%
CSA.
Intruding lateral 5–20% diameter.
Performance severely reduced
4
Performance severely
reduced
Tap roots or root mass 20–50%
CSA.
Scale deposits >20% CSA.
Sediment 20–75% diameter.
Intruding lateral 20–75%
diameter or hanging sealing ring.
Blocked or unsafe condition
5
Blocked or unsafe
condition
A5.6
Blockage/obstacle such as root
mass >50% CSA.
Debris/sediment deposits >75%
CSA.
Intruding lateral>75% diameter.
Filter drains
Filter drains should be assessed in accordance with Table A.13 for structural condition and in
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CS 551 Version 1.0.0
Appendix A. Drainage condition grade quick assessment
accordance with Table A.14 for service condition. Combined surface and subsurface filter drains are
composed of the granular backfill medium and the pipe; the condition of these two parts should be
assessed separately and the worst grade reported for the asset as a whole.
Table A.13 Filter drains - Structural condition grade quick assessment
Asset types
Structural
grade
Counterfort drain, filter drain, soakaway trench, combined surface and sub-surface
filter drain (filter media)
Example
Definition
No defects
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1
No defects
Structurally sound.
Superficial defects
2
Superficial
defects
Individual stones displaced from filter
drain, with no visible deterioration of
filter drain itself.
Minor defects
3
Minor defects
Presence of wheel rut with scattered
medium.
Major defects
4
Major defects
Encroaching earthworks.
Surface obscured (not due to surface
treatment).
Inappropriate medium (Type A in
carriageway drain).
Multiple wheel ruts with major
displacement of medium onto
carriageway.
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Appendix A. Drainage condition grade quick assessment
Table A.13 Filter drains - Structural condition grade quick assessment (continued)
Asset types
Counterfort drain, filter drain, soakaway trench, combined surface and sub-surface
filter drain (filter media)
Not fit for purpose or unsafe
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5
Not fit for
purpose or
unsafe
Combined surface and sub surface filter
drain remote from pavement edge
(excludes toe drain).
Table A.14 Filter drains - Service condition grade quick assessment
Asset types
Service grade
Counterfort drain, filter drain, soakaway trench, combined surface and
sub-surface filter drain (filter media)
Example
Definition
Clear
1
Clear
Unobstructed clean filter
material.
Superficial deposits with no loss of
performance
2
Superficial deposits with
no loss of performance
Presence of surface sediment.
Sediment build up at pavement
edge.
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Appendix A. Drainage condition grade quick assessment
Table A.14 Filter drains - Service condition grade quick assessment (continued)
Asset types
Counterfort drain, filter drain, soakaway trench, combined surface and
sub-surface filter drain (filter media)
Performance slightly reduced
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3
Performance slightly
reduced
Vegetation established at
pavement edge (obstructs
inflow).
Vegetation established in
medium.
Performance severely reduced
4
Performance severely
reduced
Filter medium surface crusted.
Blocked or unsafe condition
5
Blocked or unsafe
condition
A5.7
Filter medium blocked such that
standing water is evident.
Ditches
Ditches should be assessed in accordance with Table A.15 for structural condition and in accordance
with Table A.16 for service condition.
Table A.15 Ditches - Structural condition grade quick assessment
Asset types
Structural
grade
Ditch, grip
Example
Definition
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Appendix A. Drainage condition grade quick assessment
Table A.15 Ditches - Structural condition grade quick assessment (continued)
Asset types
Ditch, grip
No defects
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1
No defects
Uniform channel cross section.
Superficial defects
2
Superficial
defects
No loss of channel section.
Minor disturbance exposing subsoil in
ditch side, e.g. evidence of burrowing.
Exposed lining at bank top or displaced
joints in lining.
Minor defects
3
Minor defects
Some loss of channel section due to
established burrows, side slope
instability or movement, with flow
slightly impeded.
Exposed non-concrete liner in channel
side or displaced concrete liner.
4
Major defects
Obstruction of channel due to significant
slippage of side slope, with flow
severely impeded.
Exposed non-concrete liner in channel
invert or torn liner above top water level.
Concrete liner broken, not blocking
channel.
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Appendix A. Drainage condition grade quick assessment
Table A.15 Ditches - Structural condition grade quick assessment (continued)
Asset types
Ditch, grip
Not fit for purpose or unsafe
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5
Not fit for
purpose or
unsafe
Complete blockage of channel due to
collapsed side slope or concrete liner.
Severe burrowing.
Flow dammed.
Liner ripped below top water level.
Table A.16 Ditches - Service condition grade quick assessment
Asset types
Service grade
Ditch, grip
Example
Definition
Clear
1
Clear
Short grass, no sediment or debris.
Superficial deposits with no loss
of performance
2
Superficial deposits with
no loss of performance
Some vegetation growth or
accumulation of debris in
channel, e.g. long grass / reeds,
litter.
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Appendix A. Drainage condition grade quick assessment
Table A.16 Ditches - Service condition grade quick assessment (continued)
Asset types
Ditch, grip
Performance slightly reduced
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3
Performance slightly
reduced
Pools forming in channel.
Channel obstructed by vegetation
(e.g. rushes), sediment banks
retaining standing water, shrubs
becoming established.
Significant debris e.g. individual
vehicle components, building
products.
Performance severely reduced
4
Performance severely
reduced
Significant loss of channel capacity
due to heavy sediment deposition,
saplings established.
Significant debris, e.g. multiple
vehicle components.
Blocked or unsafe condition
5
Blocked or unsafe
condition
A5.8
Channel full of sediment.
Outlets virtually or completely
blocked.
Mature trees.
Large items of debris, e.g. vehicle.
Enclosed channels
Enclosed channels should be assessed in accordance with Table A.17 for structural condition and in
accordance with Table A.18 for service condition.
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Appendix A. Drainage condition grade quick assessment
Table A.17 Enclosed channels - Structural condition grade quick assessment
Asset types
Combined kerb and drainage channel, combined pipe and channel drain, linear
drainage channel
Structural grade
Example
Definition
No defects
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1
No defects
No defects.
Superficial defects
2
Superficial
defects
Chipped or weathered concrete.
Surface corrosion.
3
Minor defects
Cracked kerb-drain unit.
Cracked integral cover or
damaged removable cover.
Major defects
4
Major defects
Displaced unit.
5
Not fit for
purpose or
unsafe
Broken kerb-drain unit.
Broken integral cover or missing
removable cover.
Table A.18 Enclosed channels - Service condition grade quick assessment
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Appendix A. Drainage condition grade quick assessment
Asset types
Service grade
Combined kerb and drainage channel, combined pipe and channel drain,
linear drainage channel
Example
Definition
Clear
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1
Clear
No sediment in channel.
Superficial deposits with no loss
of performance
2
Superficial deposits with
no loss of performance
Some sediment or vegetation, or
litter on channel grating.
Performance slightly reduced
3
Performance slightly
reduced
Channel partially obstructed by
debris.
Vegetation becoming established in
gratings.
Blocked waterway.
Performance severely reduced
4
Performance severely
reduced
Significant loss of channel capacity
due to heavy sediment deposition.
Waterways obstructed by debris.
Vegetation blocking some of the
grating slots.
Blocked or unsafe condition
5
Blocked or unsafe
condition
Channel full of sediment.
Waterways completely obstructed.
Grating/inlet blocked.
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A5.9
Appendix A. Drainage condition grade quick assessment
Open channels
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Open channels should be assessed in accordance with Table A.19 for structural condition and in
accordance with Table A.20 for service condition.
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Appendix A. Drainage condition grade quick assessment
Table A.19 Open channels - Structural condition grade quick assessment
Asset types
Surface water channel, drainage channel block, edge channel
Structural
grade
Example
Definition
No defects
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1
No defects
No defects.
Superficial defects
2
Superficial
defects
Surface cracking or weathering.
Minor defects
3
Minor defects
Missing sealant at joint.
Major defects
4
Major defects
Displaced or misaligned units (pre-cast
concrete only) causing ponding.
Spalling concrete.
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Appendix A. Drainage condition grade quick assessment
Table A.19 Open channels - Structural condition grade quick assessment (continued)
Asset types
Surface water channel, drainage channel block, edge channel
5
Not fit for
purpose or
unsafe
Fractured/broken.
Table A.20 Open channels - Service condition grade quick assessment
Asset types
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Service grade
Surface water channel, drainage channel block, edge channel
Example
Definition
Clear
1
Clear
No sediment.
Superficial deposits with no loss
of performance
2
Superficial deposits with
no loss of performance
Some sediment or vegetation in
invert.
Litter in channel.
3
Performance slightly
reduced
Channel obstructed by debris,
vegetation or sediment causing
ponding in invert.
Performance severely reduced
A5.10
4
Performance severely
reduced
Significant loss of channel capacity
due to heavy sediment deposition.
Channel or gratings partially
obstructed by debris.
5
Blocked or unsafe
condition
Channel full of sediment or debris.
Gratings completely obstructed.
Grassed channels
Grassed channels should be assessed in accordance with Table A.21 for structural condition and in
accordance with Table A.22 for service condition.
Table A.21 Grassed channels - Structural condition grade quick assessment
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Appendix A. Drainage condition grade quick assessment
Asset types
Grassed surface water channel or swale
Structural
grade
Definition
Example
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No defects
1
No defects
No defects.
2
Superficial
defects
Shallow wheel rut or depression at
channel edge with no impact on flow.
3
Minor defects
Shallow wheel rut within channel slightly
impeding flow.
Major defects
4
Major defects
Deep wheel rut severely impeding flow.
Exposed geogrid.
Not fit for purpose or unsafe
5
Not fit for
purpose or
unsafe
Multiple wheel ruts with displaced soil
forming ridge.
Flow dammed.
Exposed impermeable lining.
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Appendix A. Drainage condition grade quick assessment
Table A.22 Grassed channels - Service condition grade quick assessment
Asset types
Service grade
Grassed surface water channel or swale
Example
Definition
Clear
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1
Clear
A5.11
No sediment.
2
Superficial deposits with
no loss of performance
Some sediment in invert or litter in
channel.
3
Performance slightly
reduced
Channel obstructed by debris.
Intrusive vegetation or sediment
causing ponding in invert.
Raised grass edge strip forming.
Patches of bare ground.
4
Performance severely
reduced
Significant loss of channel capacity
due to heavy sediment deposition,
or channel or gratings partially
obstructed by debris.
Extensive bare ground.
Isolated damage to vegetation by
contamination.
5
Blocked or unsafe
condition
Channel full of sediment or debris,
or extensive vegetation blocking
flow.
Gratings completely obstructed.
Completely bare ground.
Extensive damage to vegetation by
contamination.
Performance severely reduced
Ponds
Ponds should be assessed in accordance with Table A.23 for structural condition and in accordance
with Table A.24 for service condition.
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Appendix A. Drainage condition grade quick assessment
Table A.23 Ponds - Structural condition grade quick assessment
Asset types
Structural
grade
Detention basin, retention pond, sediment pond, infiltration basin, pollution
containment pond or tank, wetlands, reed bed treatment system, pond
(undifferentiated)
Example
Definition
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No defects
1
No defects
Structurally sound.
Fencing secure.
Required warning signs present.
Good vehicle access to pond.
2
Superficial
defects
Disturbance of pond side slope.
Vehicular access difficult.
3
Minor defects
Evidence of burrowing.
Slope movement evident.
Liner visible in bank.
Vehicular access obstructed.
4
Major defects
Presence of large burrows in non
water-retaining slope.
Slope slippage.
Liner exposed and displaced in bank.
Security fencing insecure.
No constructed vehicular access to
pond.
5
Not fit for
purpose or
unsafe
Presence of burrows or slope slippage
in raised water-retaining slope.
Slope failure.
Liner torn/split.
No vehicular access to pond.
Lack of adequate security fencing,
missing lifebelt or other safety
equipment where required.
Pond has vertical sides with no means
of escape.
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Appendix A. Drainage condition grade quick assessment
Table A.24 Ponds - Service condition grade quick assessment
Asset types
Service grade
Detention basin, retention pond, sediment pond, infiltration basin, pollution
containment pond or tank, wetlands, reed bed treatment system, pond
(undifferentiated)
Example
Definition
Clear
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1
Clear
2
Superficial deposits with
no loss of performance
Clear of sediment and invasive
vegetation.
Flow into or out of pond not
impeded.
Sediment deposits visible.
Invasive vegetation established on
banks.
Performance slightly reduced
3
Performance slightly
reduced
Flow into or out of pond slightly
impeded.
Sediment levels <25% inlet or outlet
pipe diameter. Invasive vegetation
in pond.
4
Performance severely
reduced
Flow into or out of pond severely
impeded.
Pools formed due to sediment.
Sediment levels >25% inlet or outlet
pipe diameter.
Invasive shrubs in pond.
Blocked or unsafe condition
5
Blocked or unsafe
condition
Flow into or out of pond blocked by
sediment.
Tree(s) in pond.
111
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A5.12
Appendix A. Drainage condition grade quick assessment
Ancillaries
Ancillaries should be assessed in accordance with Table A.25 for structural condition and in
accordance with Table A.26 for service condition.
Table A.25 Ancillaries - Structural condition grade quick assessment
Asset types
Structural grade
Standalone flow control device, interceptor, oil separator, pumping station
(overall structure and function), vortex separator
Example
Definition
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No defects
1
No defects
2
Superficial defects
No defects.
Rusty component.
Minor defects
3
Minor defects
Damaged baffle.
Structural crack.
112
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Appendix A. Drainage condition grade quick assessment
Table A.25 Ancillaries - Structural condition grade quick assessment (continued)
Asset types
Standalone flow control device, interceptor, oil separator, pumping station
(overall structure and function), vortex separator
Major defects
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4
Major defects
Loose flap valve, valve not
seating.
Missing vent pipe from oil
separator.
Missing weir sections.
Fracture.
Not fit for purpose or unsafe
5
Not fit for purpose
or unsafe
Seized or missing flap valve.
Missing handrail where
required for safety.
113
CS 551 Version 1.0.0
Appendix A. Drainage condition grade quick assessment
Table A.26 Ancillaries - Service condition grade quick assessment
Asset types
Service grade
Standalone flow control device, interceptor, oil separator, pumping
station (overall structure and function), vortex separator
Example
Definition
Clear
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1
Clear
Unobstructed with no impedance of
flow.
Superficial deposits with
no loss of performance
2
Superficial deposits with
no loss of performance
Minor accumulation of litter, sediment
or vegetation.
Performance slightly
reduced
3
Performance slightly
reduced
Flow slightly impeded due to litter,
sediment or vegetation.
4
Performance severely
reduced
Flow significantly impeded due to large
accumulations of litter, sediment or
vegetation.
Blocked or unsafe
condition
5
Blocked or unsafe
condition
Flow impeded causing surcharge.
Pollution risk.
Oil separator is full.
114
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© Crown copyright 2021.
You may re-use this information (not including logos) free of charge in any format or medium, under the terms of the
Open Government Licence. To view this licence:
visit www.nationalarchives.gov.uk/doc/open-government-licence/,
write to the Information Policy Team, The National Archives, Kew, London TW9 4DU,
or email psi@nationalarchives.gsi.gov.uk.
Design Manual for Roads and Bridges
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Drainage
Inspection & Assessment
CS 551
England National Application Annex to CS 551
Drainage surveys
(formerly SD 15/03)
Version 1.0.0
Summary
This National Application Annex sets out the National Highways-specific requirements for
drainage surveys.
Feedback and Enquiries
Users of this document are encouraged to raise any enquiries and/or provide feedback on the content and usage
of this document to the dedicated National Highways team. The email address for all enquiries and feedback is:
Standards_Enquiries@highwaysengland.co.uk
This is a controlled document.
CS 551 Version 1.0.0
Contents
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Contents
Release notes
2
Foreword
Publishing information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contractual and legal considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
3
3
Introduction
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Assumptions made in the preparation of the document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mutual recognition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
4
4
4
Abbreviations
5
E/1. General requirements (additional to CS 551, clause 2.6)
6
E/2. Normative references
7
E/3. Informative references
8
1
CS 551 Version 1.0.0
Release notes
Latest release notes
Document
code
CS 551
Version
number
1.0.0
Date of publication
of relevant change
October 2021
Changes made to
Type of change
England NAA
Change to policy, major
revision, new document
development
This ENAA has been created to carry an England-only reference to HADDMS for a drainage survey method of
measurement.
Previous versions
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Document
code
Version
number
Date of publication
of relevant change
Changes made to
2
Type of change
CS 551 Version 1.0.0
Foreword
Foreword
Publishing information
This document is published by National Highways.
This document supersedes CS 551 ENAA Rev 0, and SD 15/03 of the Manual of Contract Documents
for Highway Works, which are withdrawn.
Contractual and legal considerations
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
This document forms part of the works specification. It does not purport to include all the necessary
provisions of a contract. Users are responsible for applying all appropriate documents applicable to
their contract.
3
CS 551 Version 1.0.0
Introduction
Introduction
Background
This document gives the National Highways-specific requirements for drainage surveys.
The selection of the most appropriate survey method is detailed in CD 535 [Ref 1.I].
Assumptions made in the preparation of the document
The assumptions made in GG 101 [Ref 2.N] apply to this document.
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Mutual recognition
Where there is a requirement in this document for compliance with any part of a "British Standard" or
other technical specification, that requirement may be met by compliance with the Mutual Recognition
clause in GG 101 [Ref 2.N].
4
CS 551 Version 1.0.0
Abbreviations
Abbreviations
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Abbreviations
Abbreviation
Meaning
HADDMS
Highways Agency Drainage Data Management System
5
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CS 551 Version 1.0.0
E/1. General requirements (additional to CS 551, c...
E/1.
General requirements (additional to CS 551, clause 2.6)
E/1.1
The drainage survey shall be measured in accordance with the National Highways draft method of
measurement, available from HADDMS (Ref. HADDMS [Ref 1.N]), and any specific method of
measurement provided for the works.
6
CS 551 Version 1.0.0
E/2.
E/2. Normative references
Normative references
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The following documents, in whole or in part, are normative references for this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
Ref 1.N
National Highways (data.gov.uk). HADDMS, 'http://www.haddms.co.uk'
Ref 2.N
National Highways. GG 101, 'Introduction to the Design Manual for Roads and
Bridges'
7
CS 551 Version 1.0.0
E/3.
E/3. Informative references
Informative references
The following documents are informative references for this document and provide supporting
information.
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Ref 1.I
National Highways. CD 535, 'Drainage asset data and risk management'
8
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© Crown copyright 2021.
You may re-use this information (not including logos) free of charge in any format or medium, under the terms of the
Open Government Licence. To view this licence:
visit www.nationalarchives.gov.uk/doc/open-government-licence/,
write to the Information Policy Team, The National Archives, Kew, London TW9 4DU,
or email psi@nationalarchives.gsi.gov.uk.
Design Manual for Roads and Bridges
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Drainage
Inspection & Assessment
CS 551
Northern Ireland National Application Annex to
CS 551 Drainage surveys
(formerly SD 15/03)
Revision 0
Summary
There are no specific requirements for Department for Infrastructure Northern Ireland
supplementary or alternative to those given in CS 551.
Feedback and Enquiries
Users of this document are encouraged to raise any enquiries and/or provide feedback on the content and usage of
this document to the dedicated team in the Department for Infrastructure, Northern Ireland. The email address for all
enquiries and feedback is: dcu@infrastructure-ni.gov.uk
This is a controlled document.
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CS 551 Revision 0
Contents
Contents
Release notes
2
1
CS 551 Revision 0
Release notes
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Release notes
Version
Date
Details of amendments
0
Jun 2019
Department for Infrastructure Northern Ireland National Application Annex to
CS 551.
2
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© Crown copyright 2019.
You may re-use this information (not including logos) free of charge in any format or medium, under the terms of the
Open Government Licence. To view this licence:
visit www.nationalarchives.gov.uk/doc/open-government-licence/,
write to the Information Policy Team, The National Archives, Kew, London TW9 4DU,
or email psi@nationalarchives.gsi.gov.uk.
Design Manual for Roads and Bridges
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
Drainage
Inspection & Assessment
CS 551
Scotland National Application Annex to CS
551 Drainage surveys
(formerly SD 15/03)
Revision 0
Summary
Please contact Transport Scotland for the application of CS 551. The email address is:
TSStandardsBranch@transport.gov.scot
Feedback and Enquiries
Users of this document are encouraged to raise any enquiries and/or provide feedback on the content and usage
of this document to the dedicated Transport Scotland team. The email address for all enquiries and feedback is:
TSStandardsBranch@transport.gov.scot
This is a controlled document.
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
CS 551 Revision 0
Contents
Contents
Release notes
2
1
CS 551 Revision 0
Release notes
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
Release notes
Version
Date
Details of amendments
0
Jun 2019
Transport Scotland National Application Annex to CS 551.
2
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
© Crown copyright 2019.
You may re-use this information (not including logos) free of charge in any format or medium, under the terms of the
Open Government Licence. To view this licence:
visit www.nationalarchives.gov.uk/doc/open-government-licence/,
write to the Information Policy Team, The National Archives, Kew, London TW9 4DU,
or email psi@nationalarchives.gsi.gov.uk.
Design Manual for Roads and Bridges
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
Drainage
Inspection & Assessment
CS 551
Wales National Application Annex to CS 551
Drainage surveys
(formerly SD 15/03)
Revision 0
Summary
There are no specific requirements for Welsh Government supplementary or alternative to those
given in CS 551.
Feedback and Enquiries
Users of this document are encouraged to raise any enquiries and/or provide feedback on the content and usage
of this document to the dedicated Welsh Government team. The email address for all enquiries and feedback is:
CustomerHelp@wales.gsi.gov.uk
This is a controlled document.
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
CS 551 Revision 0
Contents
Contents
Release notes
2
1
CS 551 Revision 0
Release notes
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
Release notes
Version
Date
Details of amendments
0
Jun 2019
Welsh Government National Application Annex to CS 551.
2
Downloaded from https://www.standardsforhighways.co.uk on 02-Apr-2025, CS 551 Version 1.0.0, published: 28-Oct-2021
© Crown copyright 2019.
You may re-use this information (not including logos) free of charge in any format or medium, under the terms of the
Open Government Licence. To view this licence:
visit www.nationalarchives.gov.uk/doc/open-government-licence/,
write to the Information Policy Team, The National Archives, Kew, London TW9 4DU,
or email psi@nationalarchives.gsi.gov.uk.