sh.a .
U
K
Sh k o d ë r
Ujësjelles Kanalizime Qytet Shkoder
Kreditanstalt für Wiederaufbau
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WATER & SEWERAGE PROJECT SHKODRA
FEASIBILITY STUDY
PROJECT CONCEPT DRAFT REPORT
ANNEX No. 2
Hydraulic Modelling of the
Storm Water Drainage Network
June 2006
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i
TABLE OF CONTENTS
1
2
HYDRAULIC MODELLING OF THE STORM WATER SYSTEM ................................... 1
1.1
Generalities .............................................................................................................. 1
1.2
Software ................................................................................................................... 2
METHODOLOGY ........................................................................................................... 2
2.1
2.1.1
Topographic Survey ........................................................................................... 2
2.1.2
Modelised Storm Water Drainage System .......................................................... 2
2.1.3
Sub-Systems, Main and Sub-Catchment Areas ................................................. 3
2.2
3
Preparation of the Hydraulic Model ........................................................................... 2
Design and Calculation Criteria ................................................................................ 4
2.2.1
Slope adjustment factors .................................................................................... 4
2.2.2
Surface Sealing Rate ......................................................................................... 5
2.2.3
Rainfall Intensity ................................................................................................. 5
RESULTS ...................................................................................................................... 7
3.1
Existing Storm Water Drainage System .................................................................... 7
3.1.1
Results of the Hydraulic Modelling ..................................................................... 7
3.1.2
Conclusions with Regard to the Future Storm Water Concept ............................ 8
3.2
Future Storm Water Drainage System ...................................................................... 8
3.2.1
SW0 ................................................................................................................... 9
3.2.2
SW1: (Industrial Area) ........................................................................................ 9
3.2.3
SW2 ................................................................................................................... 9
3.2.4
SW3 ..................................................................................................................10
3.2.5
SW4 ..................................................................................................................10
3.2.6
SW5 ..................................................................................................................11
3.2.7
SW6 ..................................................................................................................11
3.3
Storm Water Drainage System Extension ................................................................11
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TABLES
Table 2-1: Slope classification categories according to DWA-A-118 ...................................... 5
Table 2-2: Characteristic Rainfall Intensities .......................................................................... 5
APPENDICES
Appendix 1:
Assessment of Surface Sealing Rate in Representative Urban Areas
Appendix 2- 1:
Hydraulic Calculation of the Existing Storm Water Drainage System
Period of Return1 in 2 years
Appendix 2- 2:
Hydraulic Calculation of the Existing Storm Water Drainage System –
Period of Return1 in 1 years
Appendix 3:
Hydraulic Calculation of the Future Storm Water Drainage System
Appendix 4:
Hydraulic Calculation of the Storm Water Drainage Network Extensions
–
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1
HYDRAULIC MODELLING OF THE STORM WATER SYSTEM
In order to assess the capacity of the existing storm water drainage system for the
planning horizon 2030 and to elaborate a suitable concept for the future storm water
drainage system, a computerised detailed hydraulic modelling of the primary and part
of the secondary storm water drainage network has been carried out.
1.1
Generalities
The verification of hydraulic capacity of a storm water system can be executed with
different methods.
Recommended are hydrodynamic computerised models, which are in position to
calculate permanently the relations between runoff and water level based on the
simulation of a dynamic model rainfall. This method is capable to simulate realistically
the conditions of overcharged collectors, partly submerged outlets and reversal of flow
directions. The storage capacity of the sewers and manholes, which have big influence
on the results, is considered within in the program. However, a reasonable application
of sophisticated hydrodynamic models requires detailed knowledge on the existing
secondary and tertiary sewerage network. Since these data are not available with the
required level of detail in the framework of this feasibility study, the hydraulic
calculation of the storm water system is based on the rational method as described
hereafter.
An hydrodynamic calculation has been carried out to cross-check the results of the
modelling based on the "Rational Method" and to investigate special conditions of the
storm water drainage system such as the impact of partly flooded discharge outlet
(outlet under the level of the Lake in condition of high water level).
The “Rational Method” is a hydrological method, which simulates the deformation of the
flood wave on its way inside the sewer pipe and takes into account the temporal
coincidences of flood-overlaps of lateral influents. It cannot be used to verify the
influence of overcharged sewers and submerged sewer outlets.
This method is based on the assumption that the biggest storm water flow in the sewer
occurs for a rainfall corresponding to the flow duration into the considered sewer
section. The rainfall intensity r(D,N) is function of the duration and frequency (period of
return) of the rain. On the basis of a rainfall with a duration of 15 min. and a selected
frequency, the relevant rainfall intensity is determined by the time coefficient factor
f.The storm water flow is calculated according to the following formula:
Q (l/s) = r(D,N) * y * f * A
The rational method uses “block” rains with constant intensities during the duration of
the rain. In the German guideline DWA – A118 (German Sewerage Association) this
method is recommended for rough verification of sewer systems as well as the
dimensioning of new sewer networks. The analysis of the existing storm water system
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as well as verification of the pre-designed concept is based on the results of the
rational method. These results have been cross-checked later with the hydrodynamic
model.
1.2
Software
The hydraulic modelling of the storm water system has been carried out with the
specialised programme HYSTEM-EXTRAN, developed at the University of Hanover,
Germany, for the run-off simulation and their transport in the sewer system. For the
verification and calculation of the storm water system according to the "rational
method", the hydrological module ZEBEV has been applied.
For the preparation of the hydraulic database the programme Barthauer BASYS has
been applied, serving as an interface to AutoCAD and the simulation programmes. The
preparation of the database as well as the hydraulic verification based on the following
methodology
2
METHODOLOGY
2.1
Preparation of the Hydraulic Model
The computerised hydraulic modelling focuses on the analysis of the existing storm
water drainage system with regard to the suitability for planning horizon 2030. The
database for the hydraulic calculation has been prepared on the basis of the
investigation and survey of the existing system as well as existing topographic maps,
satellite photographs and the Austrian Feasibility Study from 1997.
2.1.1
Topographic Survey
A topographic survey of the complete existing main storm water system has been
carried out. X and Y coordinates of the manholes, as well as cover and invert levels
and diameters or sections of the pipes have been registered. In the cases that
manholes could not be opened, the invert level has been estimated on the basis of the
average slope of the pipe between the preceding and following manhole.
A total length of approximately 54 km of the existing storm water drainage network,
including 583 manholes, has been surveyed.
2.1.2
Modelised Storm Water Drainage System
In principle all surveyed manhole have been included into the database. In the case of
two sewer running in parallel on both sides of a street, these two sewers have been
replaced in the hydraulic calculation by one single sewer with the same hydraulic
capacity.
In some cases it was necessary for some bigger catchment areas with long flow length,
in order to simulate a realistic flow duration, to add fictive sewer sections. They are
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located mainly along main roads of the city and correspond to missing secondary storm
water sections. Assumed top- and bottom levels of these fictive manholes have been
defined on the basis of the available topographic data. These manholes are numbered
with a suffix “Fi” (Example: SW1.1a_Fi).
2.1.3
Sub-Systems, Main and Sub-Catchment Areas
2.1.3.1 Existing Storm Water System
Sub-Systems of the existing storm water drainage system
The existing storm water drainage system has been divided in seven separate and
independent sub-systems discharging to separate outlets in Kir River or Shkodra Lake,
as follow:

SW0: South-eastern part of the city, drained towards Kir River;

SW1: Industrial area and urban quarter between the hospital and the catholic
cemetery, north-east of the city, discharging in Kir River;

SW2: eastern and south-eastern part of the city discharging into the Fermes
Channel;

SW3: area including the northern part of the town centre and including also the
area around Isa Boletini square and Kondi street. This sub-system discharges
into the Fermes Channel;

SW4: area including the whole town centre of Shkodra as well as the area northeast of Bishanaku street (stadium) and connected to the new Austrian Channel in
Zog 1st / Vasil Shanto street, which discharges into Shkodra Lake south-west of
the city;

SW5: western part of the city around the stadium, south-west of Bishanaku
street, discharging in Shkodra Lake;

SW6: north-western part of the city around Reshit Rusi street.
An overview of the existing storm water drainage situation, with the delimitation of the
above mentioned sub-systems, is given in Drawing no. 002-06-00.
Main and sub-catchment areas of the existing storm water drainage system
In each of the above mentioned sub-systems, main catchment areas (e.g. SW1.1,
SW1.2, etc…) have been defined according the to the up-dated drawing of the existing
sewer network, topographic data, site investigations and information provided by local
experts acquainted with the existing storm water system.
For each main catchment area has been determined the surface and other main
characteristics relevant for the hydraulic calculation as described in section 2.2.
Each of the main catchment area is divided in single sub-catchment area (e.g.
SW1.1.1. to SW1.1.5.) corresponding to a pipe section between two manholes. The
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name of the sub-catchment area correspond to the number of the upper manhole. The
area of each sub-catchment area is calculated according to the ratio of the length of the
considered sewer section to the total length of the sewer in the main catchment area.
The catchment areas have been distributed in four categories:

Existing Housing Area connected to the existing storm water system

Existing Housing Area, not yet connected to the existing system

Industrial Area connected to the existing storm water system

Future Extension Area (planning horizon 2030).
The modelised storm water network and catchment areas are shown in Drawing no.
002-06-01 and 002-06-02.
2.1.3.2 Storm Water System Extensions
Extension areas of the storm water network have been defined according to the
forecasted increase of the population and urban development in Shkodra and in the
surrounding villages as well as the proposed concept for the storm water drainage of
the city of Shkodra.
Extension areas of the storm water network, include mainly the informal areas north
and west of the city which are not equipped with a proper and functional storm water
drainage system. These sub-systems are numbered with the prefix “EX” followed by
the numbers of the sub-system and main catchment area (e.g. EX1.1 to EX1.7).
Furthermore, extensions of the storm water system have also been considered for the
village of Dobraci.
For the hydraulic calculation of the sewer extension hydraulic calculation system points
have been defined. The ground level of each of theses system points has been
measured on the available topographic maps. The number of each sub-catchment area
correspond to the number of the upper system point.
An overview of the proposed concept for the future storm water drainage of the city of
Shkodra, including the extension areas of the storm water system is given in Drawing
no. 002-09-00. Details of the sub-systems and main catchment areas which have been
considered for the hydraulic modelling of the future storm water system are shown in
Drawing no. 002-09-01 until 002-09-04.
2.2
Design and Calculation Criteria
2.2.1
Slope adjustment factors
To take into account that the run-off time on the surface of the drained area depends
on the slope, a slope adjustment factor must be defined for each catchment area. The
German guideline DWA A-118 foresees the following four different categories:
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Slope classification
category
1
2
3
4
Slope
<1%
1%-4%
4 % - 10 %
> 10 %
Table 2-1: Slope classification categories according to DWA-A-118
With regard to the topographic situation, classification category 1 has been assumed
for the complete city area. Only the hilly area in the south of the city has been classified
in category 2.
2.2.2
Surface Sealing Rate
The surface sealing rates (run-off coefficient) express the percentage of impervious
(sealed) areas leading to a storm water run-off and connected to the storm water
drainage network. This percentage has been assessed on the basis of the satellite
photograph (scale 1:1.000) for different representative areas as shown in Appendix 1.
The following rates have been found to be characteristic for the town of Prizren:
A. Town centre: ...................................................................................................65 %
B. Industrial area:.................................................................................................50 %
C. Densely urbanised areas around the town centre with detached houses ........45 %
D. Low densely urbanised sub-urban areas .........................................................35 %
In reference to the expected city development, lower surface sealing rates (15%-30%)
have been assumed for future extension area.
The surface sealing rate of each catchment area is given in the Drawings no. 002-0901 until 002-09-04.
2.2.3
Rainfall Intensity
According to the statistical analysis of rainfall data for the city of Shkodra, the hydraulic
calculation of the storm water drainage system has been carried with the following
rainfall intensities:
Period of Return
Duration
[min]
Rainfall intensity
[l/s/ha]
1 in 1 year
15
112,20
1 in 2 year
15
179,95
Table 2-2: Characteristic Rainfall Intensities
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For the hydraulic calculation using the "Rational Method", a rainfall with constant
intensity is used.
For the hydrodynamic modelling a dynamic model rainfall, is used in order to see the
propagation of the wave in the sewer pipes or channels. According to the German DWA
guidelines a model rain from the so-called Euler-II Type is recommended. An Euler-II
rainfall with a duration of 90 minutes and a period of return 1 in 2 years has been
elaborated. Characteristics of this rain are as follow:
Period of return:
n=2a
Euler-I-Regen
Euler-II-Regen
D
HN
HN
D=30min.
D=60min
D=90min
[min]
[mm]
[mm]
[mm]
[mm]
[mm]
5
9,4
9,4
3,9
2,3
2,3
10
13,3
3,9
9,4
2,9
2,3
15
16,2
2,9
2,9
3,9
2,3
20
18,5
2,3
2,3
9,4
2,9
25
20,7
2,3
2,3
2,3
3,9
30
23,0
2,3
2,3
2,3
9,4
35
24,6
1,6
-
1,6
1,6
40
26,2
1,6
-
1,6
1,6
45
27,8
1,6
-
1,6
1,6
50
29,3
1,6
-
1,6
1,6
55
30,9
1,6
-
1,6
1,6
60
32,5
1,6
-
1,6
1,6
65
33,6
1,1
-
-
1,1
70
34,8
1,1
-
-
1,1
75
35,9
1,1
-
-
1,1
80
37,0
1,1
-
-
1,1
85
38,1
1,1
-
-
1,1
90
39,3
1,1
-
-
1,1
23,0
32,5
39,3
Total:
46,0
Table 2-3: Characteristics of the Euler-II-Model Rainfall
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3
RESULTS
3.1
Existing Storm Water Drainage System
3.1.1
Results of the Hydraulic Modelling
The results of the hydraulic calculation of the existing storm water network for the
current situation are given in the attached Appendices no.1-1 (period of return 2 year),
and no. 1-2 (period of return 1 year).
These results are also shown in Drawing no. 002-08-01 (period of return 2 years) and
Drawing no. 002-08-02 (period of return 1 year).
The hydraulic modelling for the current situation shows that the existing sewer network
is completely surcharged, especially with regard to the results of the return period 1 in 2
years. Main bottlenecks are as follow:
 SW1: The complete old collector of the existing industrial area (SW1.1 to SW1.3
and SW1.7 to SW1.10);
 SW2: Almost all of the existing storm water system (SW2.5 to SW2.12), due to the
size of the connected catchment area and the missing secondary storm
water drainage;
 SW3: Major parts of the “Old line” (SW3.2 to SW3.18). However most part of the
“Old Line” sections show sufficient hydraulic capacity for a period of return of
1 year. Nevertheless, with regard to the general bad condition of the sewer
and the fact that on its major length it is running in private areas and under
existing houses, a rehabilitation is considered necessary;
 SW4: Nearly the complete storm water collector along the street “Buja Bishanaku”
(SW4.3 to SW4.9) as well as some sections along the street “Zog the 1 st”
(SW4.14 and SW4.15).
 SW5: Only two sections of the existing storm water collector (SW5.1) are
surcharged. A verification of projected new ring road collector relate to the
proposed concept, has shown some overloads near to the discharge (SW5.1
and SW5.2)
 SW6: The complete existing storm water drainage of the sub-system (SW6.2 to
SW6.8) is surcharged in cause of small diameters. It should be further
pointed out, that the designed capacities of the projected new ring road
collector have absolutely insufficient capacity.
For some sections, which are overloaded for the period of return 2 years, the
hydrodynamic calculation shows that however no water is running out of the systems
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(no flooding of the streets). The concerned sections include most of the more recently
built sewer as follow:
3.1.2

SW1:
Collector SW1.4 to SW1.6 (industrial area)

SW3:
Collector SW3.23 to SW3.25

SW4:
Collector SW4.17 to SW4.18 (funded by the Austrian Government)
Collector SW4.20 to SW4.21
Conclusions with Regard to the Future Storm Water Concept
Main conclusions of the hydraulic modelling of the existing system for the elaboration of
the future concept are as follow:
3.2

Where possible areas connected to the existing systems shall be discharged by
gravity in the receiving waters by the nearest way;

Collectors with are in good condition and have sufficient capacity will be
maintained in future;

It should be tried, as much as possible to keep existing comparatively newly
built storm water collectors (e.g. Austrian channel, Industria Area, Kelmendi
street) suitable for the future situation. Therefore where necessary, part of the
connected areas shall be diverted to other drainage areas;

In special case, existing collector which are in good condition and have
adequate capacity for a rainfall intensity with a period of return less than 2 years
but more than 1 year can be considered as suitable, especially if the
hydrodynamic calculation show that no flooding of the street occur or only for a
very short period of time;

Ongoing storm water projects, especially the one in the scope of the
construction of the new ring road, will be included in the concept as planned;
Future Storm Water Drainage System
Drawing No. 002-09-00 to 002-09-04 show the future storm water drainage concept
including rehabilitation and replacements of the existing storm water system as well as
construction of main new storm water collectors, together with the main secondary
sewers of developed area. Extension area are further incorporated in this drawings.
The results of the hydraulic modelling for the future concept (2030) are given in
Appendix no. 3.
The proposed concept for the storm water drainage of the areas currently drained by
the existing systems is as follow. It should be underlined that extension and new
construction of missing secondary and tertiary storm water collectors is required in
almost all of the areas.
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3.2.1
SW0
This area covers the south eastern part of the city along railway embankment and
discharges to the Kir River. No real and proper storm water drainage is available for the
current situation. The proposed concept is as follow:
3.2.2

New construction of primary and secondary storm water collectors (SW0.3 to
SW0.6 and SW0.10 to SW0.11) for the drainage of the developed area;

Replacement of the existing storm water collector SW0.1 which will be
surcharged due to the connection of additional areas.
SW1: (Industrial Area)
Sub System SW1 is located in the north east of Shkodra and covers the storm water
disposal of the existing industrial area. In order to maximise the utilisation of existing
assets it will be a benefit to separate the system into two drainage area (SW1-A and
SW1-B). Approximately 85% of the total area will be covered by the new Sub-System
SW1-A. Furthermore it will be pointed out, that the comparatively new constructed
storm water collector (SW1.4 to SW1.6) is surcharged for a rainfall intensity of 180
l/s/ha and a period of return 1 in 2 years (see Appendix no. 3; “utilisation ratio of
rational method”). The hydrodynamic model showed that this sections are surcharged,
but no storm water is discharging out of the system. With regard to this aspect a further
utilisation of this collector is foreseen in the future concept. Following additional
measures have been proposed in the future concept.
3.2.3

The system will be separate at manhole SW1.7.7

Replacement of the old industrial collector from SW1.1.1 to SW1.6.15

Construction of the new discharge SW1-A crossing the railway embankment
near the catholic cemetery.

Construction of a new primary storm water collector from SW1.6 to the new
discharge SW1-A.

Tertiary storm water network within the area of private industrial areas will be
provided by the owner.

Rehabilitation measures for sub-system SW1-B will be the replacement of the
existing storm water collectors SW1.9 and SW1.10.
SW2
This area covers the southern and south eastern parts of the city, where the existing
main drainage system is limited in both extend and capacity. Following measures have
been foreseen for the improvement of the current situation.

Construction of new main secondary collectors for the extension of missing storm
water drainage in developed areas (SW2.2; SW2.4; SW2.6 and SW2.8).

Most of the existing main collectors will be replaced with an increased capacity,
especially with regard to the above mentioned extension measures.
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
3.2.4
Increase of capacity of the existing open channel (SW2.15 to SW2.19) as well as
stabilisation measures of the embankment.
SW3
Consider the hydraulic results of the current situation, sub-system SW3 is absolutely
surcharged, especially the “Old Line”. This is due to the importance of the connected
catchment areas. In order to maximise the utilisation of the comparatively new
constructed main storm water collector (SW3.23 to SW3.24), parts of the lower area
will be diverted to sub-system SW4. The benefit of this measure will be the utilisation of
the capacity reserves from the Austrian funded main collector. The northern part of the
existing catchment area will be add to sub-system SW6. With regard to this aspects
following additional rehabilitation measures have to be implemented in the future
concept.
3.2.5

Construction of new main secondary collectors relate to the extension of missing
storm water drainage in developed areas (SW3.2 and SW3.3)

Some sections of existing collectors will be replaced with an increased capacity,
especially parts of SW3.5
SW4
This sub-system covers the complete town centre area. Existing capacity reserves of
the Austrian Collector is completely used for the connection of part of the existing subsystem SW3 as described above. For that reason and in order to reduce the storm
water flow to this collector and to avoid the need to replace the Austrian Collector, parts
of the north western area SW4.1 to SW4.4 (see existing situation Drawing no. 002-0600) will be diverted to sub-system SW5. Considering also the results of the
hydrodynamic verification, following measures have to be implemented within the
proposed concept:

Re-utilisation in future of the Austrian Collector (SW4.17 to SW4.18);

Replacement of some sections of the existing main collectors along street “Zog the
1st” with collectors of increased capacity (SW4.14 and SW4.15);

Extension of the storm water collector along street “Zog the 1st” from SW4.15
towards north;

Extension of new main secondary collectors according to the proposed
development of the storm water drainage in the northern part of the city areas;

Re-utilisation of the recently constructed storm water collector in the south (SW4.20
to SW4.21

Implementation of the projected new ring road collector,
recommendation to increase the capacity of section SW4.24c.
including
the
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3.2.6
SW5
Considering the connection of part of the existing sub-system SW4 to this system, as
described above, (SW5.3 to SW5.5) as well as the inadequate existing storm water
drainage, following measures have been defined:
3.2.7

Implementation of the projected new ring road collector, including
recommendation to increase some diameters of section SW5.1 and SW5.2.

Extension of a new primary collector (SW5.3 to SW5.6), designed for the drainage
of the diverted areas of sub-system SW4
the
SW6
In comparison to the the existing situation, it is foreseen to connect in future the
northern catchment areas of sub-system SW3 to sub-system SW6. This concerns the
catchment area SW3.1 to SW3.5 (see Drawing no. 002-06-00). With regard to the
insufficient capacities of the projected new ring road design following recommendations
are made:
3.3

Construction of the new ring road collector with incvreased sections compard to the
existing design;

New construction of a primary main collector along street “Reshit Rusi” (SW6.9 to
SW6.6 and SW6.6 to SW6.8)
Storm Water Drainage System Extension
The definition of extension areas based on the methodology described in
Section2.1.3.2. The forecasted future development of city of Shkodra as well as the
proposed storm water concept (2030) is shown in Drawings no. 002-09-00 to 002-0904.
Forecasted extension area are mainly located in the north as well as the existing
housing area along the shore of Lake Shkodra (west side of the new ring road).
Additional extension area are located in the south and south east of the city, where no
storm water drainage exists at the moment. Furthermore, the storm water drainage of
the villages Bahcallek (South) and Dobraci (North) have been included in the future
concept (horizon 2030).
Fifteen additional Sub-Systems have been defined for the storm water drainage of the
future extension area, which discharge directly to the Lake Shkodra or Kir River. They
have been numbered with a prefix and a suffix (for example EX1.1 to EX1.7). The
hydraulic calculation of the storm water flow for each of these areas is given in
Appendix no. 3.
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Water and Sewerage Project Shkodra – Feasibility Study
Project Concept Report – Annex 2: Storm Water Drainage Modelling
June 2006
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APPENDICES
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Water and Sewerage Project Shkodra – Feasibility Study
Project Concept Report – Annex 2: Storm Water Drainage Modelling
June 2006
_________________________________________________________________________
Appendix 1: Assessment of Surface Sealing Rate in Representative Urban Areas
Area A – Town Centre
area
rates
[m²]
[%]
Green Area
50.757
65
Roof Area
35.672
45
Yard Area
4.120
5
Street Area
10.965
14
Total:
78.669
100 %
Impervious Area
50.757
64,5 %
A
Surface Sealing Rate:
65 %
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Water and Sewerage Project Shkodra – Feasibility Study
Project Concept Report – Annex 2: Storm Water Drainage Modelling
June 2006
_________________________________________________________________________
Area B – Industrial Area
area
rates
[m²]
[%]
Green Area
57.766
65
Roof Area
33.520
29
Yard Area
8.364
7
Street Area
15.086
13
Total:
114.736
100 %
Impervious Area
56.970
49,7 %
B (Industrial Area)
Surface Sealing Rate:
50 %
___________________________________________________________________________
Water and Sewerage Project Shkodra – Feasibility Study
Project Concept Report – Annex 2: Storm Water Drainage Modelling
June 2006
_________________________________________________________________________
Area C – Densely urbanised Area with detached Houses
area
rates
[m²]
[%]
Green Area
58.775
55
Roof Area
Yard Area
28.894
7.798
28
7
Street Area
10.843
10
Total:
106.310
100 %
Impervious Areas
47.535
44,7 %
C
Surface Sealing Rate:
45 %
___________________________________________________________________________
Water and Sewerage Project Shkodra – Feasibility Study
Project Concept Report – Annex 2: Storm Water Drainage Modelling
June 2006
_________________________________________________________________________
Area D – Low densely urbanised Sub-urban Area
area
rates
[m²]
[%]
Green Area
53.531
65
Roof Area
19.375
23
Yard Area
2.280
3
Street Area
7.738
9
Total:
82.924
100 %
Impervious Areas
29.393
35,4 %
D
Surface Sealing Rate:
35 %
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Water and Sewerage Project Shkodra – Feasibility Study
Project Concept Report – Annex 2: Storm Water Drainage Modelling
June 2006
_________________________________________________________________________
Appendix 2- 1: Hydraulic Calculation of the Existing Storm Water Drainage
System – Period of Return1 in 2 years
Appendix 2- 2: Hydraulic Calculation of the Existing Storm Water Drainage
System – Period of Return1 in 1 years
Appendix 2: Hydraulic Calculation of the Future Storm Water Drainage System
Appendix 3:
Hydraulic Calculation of the Storm Water Drainage Network
Extensions
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Water and Sewerage Project Shkodra – Feasibility Study
Project Concept Report – Annex 2: Storm Water Drainage Modelling
June 2006