CSM Illicit Discharge Detection & Elimination (IDDE) 3

Question 1

NPDES MS4 permits typically require municipalities to prohibit illicit discharges through a local regulatory mechanism. What is the most common tool used to establish this legal authority?

Accepted Answer

A local stormwater ordinance or municipal code provision that prohibits non-stormwater discharges to the MS4

Answer

A resolution passed by the city council during an open meeting

Answer

A memorandum of understanding with the state environmental agency

Answer

A conditional use permit issued to each property owner

Question 2

Which of the following entities is NOT typically subject to IDDE inspections by an MS4 operator?

Accepted Answer

Federally owned facilities with their own stormwater permits

Answer

Automotive repair shops and car washes

Answer

Restaurants and food service establishments

Answer

Industrial facilities discharging to the municipal storm sewer

Question 3

A field crew finds ammonia levels elevated at a storm drain outfall during dry weather. Which type of illicit discharge source is MOST consistent with this finding?

Accepted Answer

Sanitary sewage or septic system effluent cross-connected to the storm drain

Answer

Runoff from a fertilized lawn area entering the storm drain

Answer

Cooling water discharge from an industrial HVAC system

Answer

Groundwater infiltration into a deteriorated storm pipe

Question 4

What is the recommended minimum dry period (no measurable rainfall) before conducting valid dry-weather outfall screening for illicit discharges?

Accepted Answer

72 hours

Answer

12 hours

Answer

24 hours

Answer

7 days

Question 5

Which of the following best describes the role of public education and outreach in an effective IDDE program?

Accepted Answer

It reduces illicit discharges by informing residents and businesses about what can legally enter storm drains and how to report illegal dumping

Answer

It serves primarily to meet permit reporting requirements with minimal operational impact

Answer

It is only required for Phase I MS4 permits in large urban areas

Answer

It is the responsibility of the state environmental agency, not the MS4 operator

Question 6

When documenting an IDDE field investigation, which of the following is MOST important to record for potential enforcement action?

Accepted Answer

Photographic evidence, GPS coordinates, field measurements, time and date of observation, and the name of the inspector

Answer

The weather forecast for the following week

Answer

Only the address of the suspected source facility

Answer

The estimated annual pollutant load from the discharge

Question 7

A municipality discovers that a private restaurant has been discharging grease trap waste directly into a storm drain inlet for several months. Under a typical NPDES MS4-mandated IDDE program, what sequence of actions should the municipality take?

Accepted Answer

Document the discharge, notify the discharger to cease immediately, issue a formal notice of violation, require elimination within a specified timeframe, and conduct a follow-up inspection to confirm compliance

Answer

Send an educational pamphlet, then wait for the business to self-correct within one year

Answer

Transfer the case to the state environmental agency and take no further action at the local level

Answer

Install a grease interceptor in the storm drain at municipal expense to mitigate the discharge