This work shall consist of providing and placing a geocomposite prefabricated drain system as described in the plans. The drainage system shall be installed in accordance with these specifications and in close conformity with the locations and dimensions as shown on the plans or specified by the engineer. The quantities of drain as shown on the plans may be increased or decreased at the direction of the engineer based on actual site conditions that occur during construction of the project. Such variations in quantity will not be considered as alterations in the details of construction or a change in the character of the work.


The drain conduit shall be of flexible, prefabricated, rounded rectangular shaped, composite product

The drain conduit shall be wrapped with a non-woven geotextile. This non-woven wrap shall be of a needle-punched construction consisting of long-chain polymeric fibers composed of polypropylene, polyethylene or polyamide. The fibers shall be oriented into a multi-directional stable network whereby they retain their positions relative with each other and allow the passage of water as specified. The fabric shall be free of any chemical treatment or coating, which reduces permeability and shall be inert to chemicals commonly found in soil. The geotextile shall conform to the following minimum average roll values.

The drainage core shall be made of a high-density polyethylene. The core shall be constructed using interconnected corrugated pipes that define and provide the flow channels and structural integrity of the drain. The geotextile shall function only as a filter. The core of the edge drain shall conform to the following physical property requirements.

Multi-Flow meets or exceeds these specifications.

The fittings used with the edge drain shall be of a snap together design. In no case shall any drainage product be joined without the use of the manufacturers connector designed specifically for the purpose.

Pipe for edge drain outlet laterals shall be either PVC pipe meeting the requirements of ASTM D-2729 or ASTM F-949, or high-density polyethylene pipe meeting the requirements of AASHTO M252.

A rodent screen made of 0.3 inch by 0.3 inch square opening size, 0.063 inch gauge, stainless steel or galvanized, welded wire mesh shall be installed in each outlet lateral line. When using galvanized welded wire mesh, the rodent screen shall be galvanized after it has been formed to the shape and dimensions shown on the plans or specified by the engineer.


The amount of trench excavated at any time shall not exceed the amount of drain that can be set and backfilled completely in one working day. The trench shall be 4 inches wide and at the depth specified in the plans. The drain product shall be centered in the trench, and backfilled with clean sand whose particle size is defined as less than 5% retained on a #10 screen, and less than 5% passing through a # 30 screen. No more than 1% shall pass a #50 screen. (all US Standard Sieve sizes)

The trench excavations for the drain and outlet laterals shall be to the lines and grades shown on the Plans. Over excavation in the bottom of the excavation shall be backfilled to the proper grade with excavated material or sand prior to the placement of the drain.

Fittings for the drain shall be installed in accordance with the manufacturer’s recommendations.

Backfill shall be placed in maximum of 18-inch loose lifts. Compaction of the backfill shall be done in accordance with the plans or as directed by the engineer.

Any damaged edge drain or outlet lateral shall be replaced or repaired by splicing in an undamaged section of drain.