LARE LARE Stormwater Management 4

Question 1

Which soil hydrologic group has the highest infiltration rate and lowest runoff potential?

Accepted Answer

Group A

Answer

Hydrologic Soil Group A soils (typically sandy or gravelly) have the highest infiltration rates and lowest runoff potential due to their large pore sizes.

Question 2

A landscape architect is designing a rain garden with a ponding depth of 6 inches. The measured soil infiltration rate is 0.5 inches/hour. Approximately how many hours will it take to drain after a storm?

Accepted Answer

12 hours

Answer

Dividing the ponding depth (6 inches) by the infiltration rate (0.5 in/hr) gives a drain time of 12 hours.

Question 3

Which of the following is a characteristic of a 'first flush' in urban stormwater runoff?

Accepted Answer

The highest concentration of pollutants typically occurs early in a storm event

Answer

The 'first flush' phenomenon describes the elevated pollutant concentrations found in the initial portion of stormwater runoff as pollutants accumulated between storms are mobilized.

Question 4

What is the function of an anti-seep collar (seepage collar) in a stormwater pond embankment?

Accepted Answer

To prevent piping failure along the outlet pipe through the embankment

Answer

Anti-seep collars increase the seepage path length along the pipe-embankment interface, preventing piping failure — a major cause of embankment dam failure.

Question 5

Which stormwater management strategy best addresses the problem of stream temperature increase caused by urban runoff?

Accepted Answer

Directing runoff through shaded riparian buffers or infiltrating it before it reaches streams

Answer

Infiltrating runoff or routing it through shaded riparian buffers reduces thermal loading to streams by preventing sun-heated impervious surface runoff from direct discharge.

LARE Test Practice Test

LARE Test Practice Test

LARE LARE Stormwater Management 4