Construction Site BMPs and Implementation Flashcards

What is the primary function of a silt fence?

Answer: To act as a barrier that slows sheet flow and allows sediment to settle out before runoff passes through

Silt fences intercept sheet flow runoff, ponding water temporarily so sediment settles out before the filtered water passes through the geotextile fabric.

Which of the following is a correct installation requirement for a silt fence?

Answer: Bury the bottom of the fabric in a trench and backfill to prevent undercutting

Trenching and backfilling the fabric bottom prevents water from tunneling under the fence, which is the most common cause of silt fence failure.

What is a 'construction entrance' or 'stabilized pad' BMP designed to do?

Answer: Remove mud and dirt from vehicle tires before they exit the site onto public roads

Stabilized construction entrances use crushed stone or other coarse material to knock mud off tires, preventing sediment tracking onto public streets.

Hydroseeding is most effectively used as:

Answer: A temporary or permanent vegetative stabilization method applied as a slurry to exposed slopes

Hydroseeding delivers a mixture of seed, mulch, fertilizer, and water in a slurry that adheres to slopes, providing rapid vegetative cover for erosion control.

When should temporary BMPs be removed from a construction site?

Answer: After the disturbed area has achieved adequate permanent stabilization with established vegetation

Temporary BMPs should remain in place and be maintained until permanent vegetation or other stabilization is established and capable of controlling erosion without them.

What is the recommended maximum drainage area for a silt fence installation?

Answer: 0.25 to 1 acre per 100 linear feet, typically with slopes less than 50%

Silt fences are designed for small drainage areas and gentle to moderate slopes; exceeding design limits causes premature failure and loss of sediment control effectiveness.