NATURAL RESOURCES CONSERVATION SERVICE

**Idaho**

# CONSTRUCTION SPECIFICATIONS

**FOR**

# STRUCTURES FOR WATER CONTROL

**(CULVERT)**

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(Owner/Operator)

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(Project Title)

GENERAL

Installation shall be in accordance with an approved design and plan.
Details of construction shown on the drawings but not included herein
are considered as a part of this specification.

Construction operations shall be carried out in a manner to ensure that
erosion and air and water pollution are minimized. All equipment shall
be fueled at locations away from the edge of streams or other water
bodies. Sediment control fencing or other measures shall be used to
prevent storm water generated sediment from entering water bodies.

Construction activities shall be in accordance with applicable OSHA
regulations.

SITE PREPARATION

The foundation area for the culvert pipe and headwalls as applicable
shall be cleared of all trees, roots, stumps, brush, boulders, sod and
debris.

EXCAVATION

Excavation will be to the depths and widths needed to install the
culvert to the lines and grades shown on the drawings. Any over
excavation will be backfilled with selected material and compacted to
the density of the surrounding undisturbed materials. The pipe will be
placed on a firm foundation.

##### 

MATERIALS

[Pipe]{.underline}. Corrugated metal pipe shall be zinc-coated meeting
the requirements listed in one of the following standards.

> ASTM A 760 Pipe, Corrugated Steel, Zinc Coated
>
> Federal Specification WW-P-402C Pipe, Corrugated (Aluminum Alloy
> Amend. 1)
>
> Federal Specification WW-P-405B Pipe, Corrugated Iron or Steel, Zinc
> Coated (Amend.1)
>
> AASHTO M 36 Zinc Coated (Galvanized) Corrugated Iron or Steel Culverts
> and Underdrains
>
> AASHTO M 196 Corrugated Aluminum Alloy Culverts and Underdrains (Amend
> AASHTO 196)
>
> AASHTO M 245 Precoated, Galvanized Steel Culverts and Underdrains
>
> AASHTO M 257 Steel Sheet, Aluminum Coated (Aluminum Type II) by the
> Hot Dip Process for Sewer & Drainage Pipe

High density polyethylene pipe (HDPE) shall meet one of the following
standards:

> AASHTO M 294, Standard Specification for Corrugated Polyethylene Pipe,
> 300 to 1200 mm diameter (12"-48")
>
> AASHTO MP7, Standard Specification for Corrugated Polyethylene Pipe,
> 1350 to 1500 mm diameter (54"-60")

Pipe bands or couplers shall meet the requirements of the applicable
pipe specification, except that no flange (channel), smooth slab or
dimple band shall be used. Gaskets shall meet the requirements of ASTM C
443 or ASTM F 477 as appropriate.

Other pipe materials when specified shall meet the requirements as
listed on the drawings or in the "ADDITIONAL SPECIFICATIONS".

[Coatings]{.underline}. All metal items, with the exception of aluminum
and galvanized metal, shall be painted with two coats of synthetic
primer paint and one coat of aluminum paint or an approved equal
coating. Any damage to zinc coating shall be repaired by thoroughly
brushing and cleaning the damaged area and painting.

HEADWALLS

Headwalls when specified on the drawings shall be of the type and
materials and be constructed to the lines and grades as shown on the
drawings. Refer to drawings and/or "ADDITIONAL SPECIFICATIONS" for
applicable construction specifications.

BACKFILL

Backfill materials shall be free of rocks, stones, sod, brush, roots, or
other perishable or unsuitable material. Cobble and rock fragments
having a maximum dimension of more than two inches shall not be used
within 1 foot of the pipe. To the extent they are suitable excavated
materials will be used to complete the necessary backfill. No fill shall
be placed on a frozen surface. Snow or ice shall not be incorporated
into any fill.

The moisture content of fine grained fill material shall be maintained
within the limits required to prevent the adherence of the fill material
to the compacting equipment and ensure the crushing and blending of the
soil clods. Generally when soil material is squeezed in the hand it will
retain a ball shape, but there will not be free water on the surface.
Supplemental water, when required, shall be applied to get water
uniformly dispersed throughout the fill materials.

Required backfill will be brought up at approximately uniform height
along both sides of the pipe.

Hand directed tamper compacted fills shall be placed in layers not
exceeding 4 inch thickness prior to being compacted. The backfill
material shall be compacted to a density equal to that of the adjacent
ground. Hand directed tampers or compactors shall be used on areas not
accessible to heavy compaction equipment and within 2 feet of the pipe
and headwalls. The passage of heavy equipment will not be allowed over
the pipe until the compacted backfill has been placed a minimum of two
feet over the top of the pipe. The layer thickness for equipment
compacted fills shall not exceed 8 inches prior to compaction.

RIPRAP

Rock when specified shall be angular to subangular in shape, dense and
durable stone of the size and gradation shown on the drawings.

ADDITIONAL SPECIFICATIONS