Section Cover Sheet
Section 02234
Topsoil and Subsoil Stripping
2006-10-31
Use this section to specify requirements for Topsoil and Subsoil stripping. This section applies
to stripping requirements for Site areas that will be affected by the Temporary and Permanent
Work including excavation and borrow areas; fill placement areas; temporary roads: including
temporary access roads, haul roads, detours; construction facilities, lay down and parking
areas, Minister’s site office access; and stockpile areas, including Topsoil stockpiles.
Normal practice is to reclaim areas that will be returned to its original or equivalent land use in
the foreseeable future, and where productivity of the land is a concern. This will typically
require that topsoil and subsoil, if present, are stripped and subsequently replaced on areas
where significant disturbance has occurred (i.e. excavation or fill placement). Reclamation will
usually also apply to any private lands.
For areas that will not be returned to original or equivalent land use, and where productivity of
the land is not a concern, these areas are normally landscaped. For landscaped areas, only
the topsoil is stripped and replaced. This will usually also apply to lands within the permanent
right-of way for the project.
This approach is consistent with the Environmental Protection and Enhancement Act which
specifies that topsoil must be conserved, and that the lands be returned to equivalent
productivity. The Act is silent on the question of subsoil stripping, however practice has
shown, that in most situations, stripping and replacing of subsoil is required in order to meet
that objective.
For canal rehabilitation projects, the typical approach is to strip only topsoil within the canal
right of way, and to strip topsoil and subsoil within those borrow areas that will be returned to
its original or equivalent land use. For a dam and reservoir project, typically only topsoil is
stripped from required excavation areas including the footprint of the dam and spillway
channels, while topsoil and subsoil is stripped within borrow areas that will be returned to its
original or equivalent land use.
For sites that are sufficiently large or complex, the involvement of a soils specialist as part of
the environmental study phase or preliminary design phase to survey the site and develop
stripping recommendations may be warranted. This requirement, as well as the criteria that
will be used to establish topsoil and/or subsoil stripping areas, should be reviewed with Alberta
Transportation.
Edit this section to suit the Contract requirements.
Heading of Specification Text
Part 1
General
1.1
Definitions
Specification Note
CWMS Civil Works Master Specification
Alberta Transportation
Master Specification System
Page 1
Section Cover Sheet
Section 02234
Topsoil and Subsoil Stripping
2006-10-31
Heading of Specification Text
Specification Note
.1 & .2
Edit as required to suit the site conditions.
[.3]
Include and co-ordinate with clause 3.3 if required.
1.2
References
[1.3]
[Submittals]
Part 2
Products
Part 3
Execution
3.1
Protection of Existing Facilities
3.2
Stripping
If frozen conditions cannot be avoided, specify the
location where frozen materials are to be stockpiled
and determine the eventual use of the material
recognizing that the material may be a mixture of
Topsoil and Subsoil. Edit the clauses as required to
recognize the mixture of Topsoil and Subsoil.
.3
Edit as required.
[.4] & [.6]
Include for winter construction of canals or other
similar works in order to minimize freezing of the
underlying materials (mineral soils) which will be
excavated and, if suitable, incorporated in fills.
.5
Edit as required.
.7
Identify specific borrow areas where Subsoil
stripping is required after Topsoil stripping.
.8
Delete “or as established by the Minister” when
stripping is performed under a Lump Sum method
of payment.
3.3
Include this clause where a large amount of
stripping is required.
-
Not Used
[Removal of Unsuitable Organic
Soils]
Include and co-ordinate with clause 1.1.3 if
required.
Co-ordinate with Section 02315 –
Excavation or Section 02316 – Excavation [Canal].
CWMS Civil Works Master Specification
Alberta Transportation
Master Specification System
Page 2
Section Cover Sheet
Section 02234
Topsoil and Subsoil Stripping
2006-10-31
Heading of Specification Text
.1 & .2
3.4
Specification Note
Edit as required.
Stockpiling
Edit to recognize the mixture of Topsoil and Subsoil
as noted above.
.1 .2 & .3
Edit as required.
.4
Edit as required.
.7
Edit as required.
.8
Edit as required.
END OF COVER SHEET
CWMS Civil Works Master Specification
Alberta Transportation
Master Specification System
Page 3
Tender No.: [
]
PART 1
GENERAL
1.1
DEFINITIONS
1.2
Section 02234
Topsoil and Subsoil Stripping
Page 1
.1
“Topsoil” means the uppermost part of the soil, ordinarily moved in tillage, or its
equivalent in uncultivated soils, and normally ranging in depth from [50 mm to
450 mm] [
]. It corresponds to the surface “A” (organo–mineral)
horizon of the soil profile as defined by the Canadian System of Soil
Classification.
.2
“Subsoil” means the portion of soil material that lies immediately beneath the
Topsoil extending to root depth. In exceptional cases, subsoil may be up to
[1500 mm] [
] in depth. It corresponds to the “B” horizon and
the upper portion of the parent material as defined by the Canadian System of
Soil Classification. In some soils there is no “B” horizon.
[.3]
“Unsuitable Organic Soils” means soils that contain organic materials and are not
suitable for use as earthwork materials or as Topsoil and Subsoil. These soils
would include soils that contain too much organic matter for earthwork materials,
are contaminated, or do not meet the requirements of Soil Quality Criteria
Relative to Disturbance and Reclamation.
REFERENCES
.1
Provide Topsoil and Subsoil stripping in accordance with the following standards
(latest revision) except where specified otherwise.
.2
Canadian Soil Survey Committee, 1998, Research Branch, Canada Department
of Agriculture, Publication 1646
.1
.3
Soil Quality Criteria Working Group, Soil Reclamation Subcommittee, Alberta
Soils Advisory Committee, Alberta Agriculture, March 1987 – Reprinted
November 1993, Conservation and Development Branch, Alberta Agriculture
.1
[1.3]
Canadian System of Soil Classification
Soil Quality Criteria Relative to Disturbance and Reclamation
[SUBMITTALS]
.1
Provide the following submittals.
.2
A stripping plan at least 15 days prior to commencing stripping operations that
indicates the limits of stripping in each area; the schedule for such work; and, the
methods and procedures that will be used for stripping and handling stripped
materials; and for preventing wind and water erosion.
Tender No.: [
Section 02234
Topsoil and Subsoil Stripping
Page 2
]
–
PART 2
PRODUCTS
PART 3
EXECUTION
3.1
PROTECTION OF EXISTING FACILITIES
.1
3.2
NOT USED
Locate and protect utility lines, survey reference points, instrumentation, culverts,
and all other existing facilities before commencing stripping operations.
STRIPPING
.1
Do not strip any area without prior authorization of the Minister.
.2
Do not drive on undisturbed areas except for performance of the stripping
operation. Stay on temporary roads: including temporary access roads, haul
roads, detours; construction facilities, lay down and parking areas, Minister’s site
office access, and do not disturb grassed or natural areas.
.3
Strip Topsoil from the areas where [Common Excavation, Structure Excavation,
and Borrow Area Excavation] and fill placement are required.
[.4]
Do not strip Topsoil from areas more than [500] m in advance of [canal]
excavation and fill placement operations.
.5
Strip Topsoil from [temporary roads: including temporary access roads, haul
roads, detours; construction facilities, lay down and parking areas, Minister’s site
office access; and stockpile areas including Topsoil stockpiles].
[.6]
Sequence Topsoil and Subsoil stripping to minimize the exposed areas and
protect underlying mineral soil from freezing. Where frost penetration has
occurred prior to the commencement of Topsoil and Subsoil stripping in a
particular area, the Minister will adjust the depth of stripping to include the frozen
material.
.7
Within [borrow areas] [
.8
Strip Topsoil and Subsoil to the depths specified in the Contract Documents [or
as established by the Minister].
.9
Strip Topsoil and Subsoil separately to prevent admixing.
.10
Sequence, stagger, and conduct stripping and excavation operations so that
undesirable mineral soil does not become mixed with Topsoil or Subsoil.
.11
Use equipment with precise depth control, such as a grader, when stripping
shallow or variable depths of material.
], strip Subsoil after the topsoil has been removed.
Tender No.: [
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Section 02234
Topsoil and Subsoil Stripping
Page 3
.12
Suspend stripping operations during rain, snow, wet ground conditions, high
winds, or other conditions that may result in contamination or loss of material.
.13
Drain surface water away from the stripped areas to prevent ponding and
infiltration in fill placement areas.
[3.3]
[REMOVAL OF UNSUITABLE ORGANIC SOILS]
.1
Excavate Unsuitable Organic Soil in accordance with Section [02315] [02316] –
[Excavation] [Excavation [Canal]]. The Minister will determine the extent of
Unsuitable Organic Soil.
.2
Dispose of Unsuitable Organic Soil at [waste disposal area [nos.
] [Waste Fill
zones] [or at locations established by the Minister], and bury under a minimum
cover of 1 m of mineral soil.
3.4
STOCKPILING
.1
Stockpile Topsoil from [Common Excavation, Structure Excavation, and Borrow
Area Excavation], and fill placement areas [adjacent to the stripped area and
within the Site Limits as authorized by the Minister] [at locations specified in the
Contract Documents] [or as established by the Minister].
.2
Stockpile Topsoil from [ temporary roads: including temporary access roads, haul
roads, detours; construction facilities, lay down and parking areas, Minister’s site
office access; and stockpile areas except for Topsoil stockpiles] adjacent to the
stripped area and within the Site Limits as authorized by the Minister.
.3
Stockpile Subsoil from [Borrow Area Excavation] and [
] areas [adjacent
to the stripped area and within the Site Limits as authorized by the Minister] [at
locations specified in the Contract Documents] [or as established by the
Minister].
.4
Separately stockpile Topsoil, Subsoil, [Topsoil with frozen materials,] [and
Subsoil with frozen materials].
.5
Maintain a minimum separation of 3 m between stockpiles of differing materials.
.6
Use silt fences and other erosion control measures to prevent soil loss from the
stockpiles due to wind or water erosion.
.7
Do not interfere with drainage courses with stockpiled material. Keep stockpiles
a minimum distance of [30] m from a river, stream, lake, reservoir or other
surface bodies of water.
Tender No.: [
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Section 02234
Topsoil and Subsoil Stripping
Page 4
.8
Do not stockpile material at slopes steeper than [3H:1V].
.9
Maintain stockpiles in a condition meeting the above requirements.
END OF SECTION