CSM Inspection Monitoring & Maintenance Procedures 2

Question 1

During a post-storm inspection of a wet detention pond, an inspector notices the outlet structure's trash rack is 60% clogged with debris. What is the most appropriate immediate action?

Accepted Answer

Remove debris immediately to restore hydraulic function and prevent flooding risk

Answer

A heavily clogged trash rack significantly restricts outflow and can cause upstream flooding, so immediate debris removal is required to restore design hydraulic capacity.

Question 2

A stormwater inspector finds that sediment has accumulated to 40% of the design storage volume in a dry detention basin. According to standard CSM maintenance thresholds, what action is triggered?

Accepted Answer

Sediment removal is required, as the threshold is typically 25–33% capacity loss

Answer

Most stormwater management standards require sediment removal when accumulation reduces storage capacity by 25–33%, and 40% clearly exceeds that threshold.

Question 3

Which monitoring parameter is MOST critical to measure at the inlet and outlet of a bioretention cell to assess its pollutant removal performance?

Accepted Answer

Total suspended solids (TSS) and nutrient concentrations

Answer

TSS and nutrient (nitrogen and phosphorus) concentrations measured at inlet and outlet allow calculation of pollutant removal efficiency, the primary performance metric for bioretention.

Question 4

An inspector observes seepage emerging from the downstream face of a stormwater pond embankment two feet below the crest. This condition MOST likely indicates:

Accepted Answer

Internal erosion or piping — a potentially critical structural failure mode

Answer

Seepage on the downstream face of an embankment, especially near the crest, is a warning sign of internal erosion or piping that can lead to catastrophic embankment failure.

Question 5

When inspecting a grass-lined swale for maintenance needs, which condition would MOST warrant immediate corrective action?

Accepted Answer

Rilling and erosion channels cutting through the swale bottom longitudinally

Answer

Longitudinal rilling in a grass swale indicates flow velocities are exceeding the protective capacity of the vegetative cover, leading to accelerating erosion that must be corrected.

(CSM) Certified Stormwater Manager Practice Test

(CSM) Certified Stormwater Manager Practice Test

CSM Inspection Monitoring & Maintenance Procedures 2