CEPSCI Water Quality Monitoring and Testing 2 — Questions and Answers
Question 1: What is the purpose of collecting a background (upstream) sample during stormwater monitoring at a construction site?
- To determine the flow rate of the receiving stream
- To establish baseline water quality and isolate site contributions from natural conditions (Correct answer)
- To satisfy NPDES permit record-keeping requirements only
- To measure the dilution factor of the receiving water body
Correct answer: To establish baseline water quality and isolate site contributions from natural conditions
An upstream background sample establishes pre-existing water quality conditions so that the site's contribution to turbidity or other parameters can be accurately identified.
Question 2: A construction inspector observes that discharge turbidity is 320 NTU and the benchmark is 250 NTU. What is the required response under the EPA CGP?
- No action is required unless the exceedance occurs three consecutive times
- Document the exceedance and immediately review and modify the SWPPP and BMPs (Correct answer)
- Suspend all construction activity until turbidity returns to below benchmark
- Notify the local fire department and health department within 24 hours
Correct answer: Document the exceedance and immediately review and modify the SWPPP and BMPs
A benchmark exceedance under the EPA CGP triggers a requirement to review the SWPPP, identify causes, and modify or add BMPs to reduce sediment discharge.
Question 3: What does the term 'effluent limit' mean in the context of construction stormwater monitoring?
- A suggested target value for turbidity that triggers BMP review
- A legally enforceable maximum concentration that must not be exceeded in discharge (Correct answer)
- The minimum flow rate at which samples must be collected
- A voluntary industry standard for water quality at construction exits
Correct answer: A legally enforceable maximum concentration that must not be exceeded in discharge
An effluent limit is a legally binding numeric standard in an NPDES permit; exceeding it constitutes a permit violation, unlike a benchmark which is a trigger for corrective action.
Question 4: Which federal regulation requires construction sites disturbing one or more acres to obtain NPDES permit coverage and implement water quality monitoring?
- Clean Air Act Section 112
- Safe Drinking Water Act
- Clean Water Act Section 402 (Correct answer)
- Resource Conservation and Recovery Act
Correct answer: Clean Water Act Section 402
Clean Water Act Section 402 establishes the NPDES permit program, which requires stormwater discharge permits and water quality monitoring for construction sites of one acre or more.
Question 5: When recording water quality monitoring data in a field logbook, which piece of information is NOT typically required?
- Date and time of sample collection
- Name of the sampler
- Weather conditions during sampling
- The GPS coordinates of the nearest downstream municipality (Correct answer)
Correct answer: The GPS coordinates of the nearest downstream municipality
Standard field monitoring records require date, time, sampler identity, weather, location, and measurement values — the coordinates of a downstream municipality are not a required data field.
Question 6: A construction site is located adjacent to a cold-water fishery. Which additional water quality parameter may be especially important to monitor beyond standard turbidity?
- Dissolved oxygen (Correct answer)
- Total dissolved solids
- Electrical conductivity
- Color units
Correct answer: Dissolved oxygen
Cold-water fisheries are highly sensitive to dissolved oxygen depletion, which can be exacerbated by elevated sediment loads and organic matter in runoff.
Question 7: How frequently must stormwater monitoring typically be performed under the EPA Construction General Permit when there is a qualifying storm event?
- Once per construction season regardless of number of storm events
- Within 4 business days after the storm event
- Once every 7 calendar days and within 24 hours of a 0.25-inch or greater storm (Correct answer)
- Only when visible sediment discharges are observed by the inspector
Correct answer: Once every 7 calendar days and within 24 hours of a 0.25-inch or greater storm
The EPA CGP requires inspections at least every 7 days and within 24 hours following a storm event of 0.25 inches or greater to check BMP performance and document conditions.
CEPSCI Water Quality Monitoring and Testing 2
What is the purpose of collecting a background (upstream) sample during stormwater monitoring at a construction site?