CSM Best Management Practices (BMPs) & Design 2

Question 1

Which BMP type removes pollutants primarily through settling and sedimentation rather than biological uptake?

Accepted Answer

Wet detention pond

Answer

Wet detention ponds rely on extended hydraulic retention time to allow suspended solids and associated pollutants to settle out.

Question 2

When sizing a bioretention cell, the typical ponding depth is limited to avoid anaerobic conditions in the media. What is the commonly accepted maximum ponding depth?

Accepted Answer

12 inches

Answer

Most design guidelines limit bioretention ponding depth to 12 inches to prevent anaerobic conditions that inhibit plant survival and pollutant treatment.

Question 3

A site designer wants to use a dry extended detention basin. Which pollutant removal mechanism is least effective in this BMP compared to a wet pond?

Accepted Answer

Biological nutrient uptake by aquatic plants

Answer

Dry basins drain between storms and lack a permanent pool, so aquatic vegetation cannot establish and biological nutrient uptake is minimal.

Question 4

Under the 'runoff volume reduction' approach to stormwater management, which BMP best addresses the water quality volume by retaining and infiltrating the first flush?

Accepted Answer

Infiltration basin sized to drawdown within 72 hours

Answer

An infiltration basin that fully drawdowns the water quality volume within 72 hours achieves maximum volume reduction by returning runoff to groundwater.

Question 5

Which soil characteristic most directly limits the feasibility of infiltration BMPs at a given site?

Accepted Answer

Saturated hydraulic conductivity (Ksat)

Answer

Saturated hydraulic conductivity determines how quickly water moves through soil; sites with Ksat below 0.5 in/hr are typically poor candidates for infiltration BMPs.

(CSM) Certified Stormwater Manager Practice Test

(CSM) Certified Stormwater Manager Practice Test

CSM Best Management Practices (BMPs) & Design 2