BMP_C234_-_Vegetated

1.39.1 Purpose

Vegetated strips reduce the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow.

1.39.2 Conditions of Use

Vegetated strips may be used downslope of all disturbed areas.

Vegetated strips are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Convey concentrated flows to a sediment pond. The only circumstance in which overland flow can be treated solely by a strip, rather than by a sediment pond, is when the criteria shown in Table 3 - 13: Vegetated Strips are met.

Table 3 - 13: Vegetated Strips
Average Slope	Slope Percent	Flowpath Length
1.5H:1V or less	67% or less	100 feet
2H:1V or less	50% or less	115 feet
4H:1V or less	25% or less	150 feet
6H:1V or less	16.7% or less	200 feet
10H:1V or less	10% or less	250 feet

1.39.3 Design and Installation Specifications

The vegetated strip shall consist of a minimum of a 25-foot wide continuous strip of dense vegetation with permeable topsoil. Grass-covered, landscaped areas are generally not adequate because the volume of sediment overwhelms the grass. Ideally, vegetated strips shall consist of undisturbed native growth with a well-developed soil that allows for infiltration of runoff.

The slope within the strip shall not exceed 4H:1V.

Delineate the uphill boundary of the vegetated strip with clearing limits.

1.39.4 Maintenance Standards

Seed any areas damaged by erosion or construction activity immediately and protect with mulch.

If more than 5 feet of the original vegetated strip width has had vegetation removed or is being eroded, install sod.

If there are indications that concentrated flows are traveling across the vegetated strip, surface water controls must be installed to reduce the flows entering the vegetated strip, or install additional perimeter protection.