Construction Site Best Management Practices Flashcards

What is the purpose of a rock check dam in a drainage channel?

Answer: To slow flow velocity, reduce channel erosion, and trap sediment in the channel between storm events

Rock check dams reduce flow velocity in channels, decreasing erosive shear stress and trapping sediment between the dam and the next upstream dam during and after storm events.

Coir logs are most commonly used for:

Answer: Shoreline and streambank stabilization and as check dams in shallow swales

Coir logs are biodegradable rolls of coconut fiber used to stabilize streambanks, shorelines, and shallow swales, providing temporary structural support while vegetation establishes.

What is a wattle or straw roll used for on construction sites?

Answer: A linear sediment barrier or flow check installed on slopes or in swales to slow runoff and trap sediment

Wattles are installed perpendicular to flow on slopes or in swales to interrupt sheet flow, slow runoff velocity, promote infiltration, and trap sediment.

What does it mean to daylight a drainage pipe on a slope?

Answer: Bring the pipe outlet to the surface at the base of the slope, requiring outlet protection to prevent scour

Daylighting a pipe means bringing its outlet to the surface, typically at the base of a slope, where outlet protection such as riprap must be installed to dissipate energy and prevent scour.

Which BMP is most appropriate for protecting a storm drain inlet in a parking lot?

Answer: A curb inlet protection device or filter bag designed to fit the specific inlet type

Curb inlet protection devices and sediment filter bags are engineered to fit standard curb inlet dimensions, effectively trapping sediment while allowing flow to continue into the drainage system.

What is the correct installation practice for silt fence to prevent undermining?

Answer: Bury the bottom 6 to 8 inches of fabric in a trench that is backfilled and compacted

Silt fence must have the bottom 6 to 8 inches of fabric buried in a compacted trench to prevent water from undercutting beneath the fence and bypassing the sediment control.