CES Water Quality & Watershed Management 1 — Questions and Answers
Question 1: What is the primary federal law governing water quality in the United States?
- Clean Water Act (CWA) (Correct answer)
- Safe Drinking Water Act
- National Environmental Policy Act
- Water Resources Development Act
Correct answer: Clean Water Act (CWA)
The Clean Water Act (1972) is the principal federal law regulating the discharge of pollutants into US waters and establishing water quality standards for surface waters.
Question 2: What is a Total Maximum Daily Load (TMDL)?
- The maximum amount of a pollutant a water body can receive and still meet water quality standards (Correct answer)
- The total amount of water a treatment plant can process daily
- The maximum daily water usage allowed per household
- The total weight of sediment in a river per day
Correct answer: The maximum amount of a pollutant a water body can receive and still meet water quality standards
A TMDL calculates the maximum pollutant load a water body can assimilate while meeting water quality standards, allocating that capacity among point and nonpoint sources with a margin of safety.
Question 3: What is the difference between point source and nonpoint source water pollution?
- Point sources discharge from identifiable locations (pipes, outfalls); nonpoint sources come from diffuse areas (runoff, atmospheric deposition) (Correct answer)
- Point sources are natural; nonpoint sources are man-made
- Point sources affect groundwater; nonpoint sources affect surface water
- There is no meaningful distinction between the two
Correct answer: Point sources discharge from identifiable locations (pipes, outfalls); nonpoint sources come from diffuse areas (runoff, atmospheric deposition)
Point sources have discrete, identifiable discharge locations (factory pipes, sewage outfalls) regulated by NPDES permits. Nonpoint sources are diffuse (agricultural runoff, urban stormwater) and are harder to regulate.
Question 4: What does BOD (Biochemical Oxygen Demand) measure in water quality assessment?
- The amount of dissolved oxygen consumed by microorganisms to decompose organic matter in water (Correct answer)
- The total number of bacteria in a water sample
- The pH level of the water
- The concentration of heavy metals in water
Correct answer: The amount of dissolved oxygen consumed by microorganisms to decompose organic matter in water
BOD measures the oxygen required by aerobic microorganisms to break down organic material in water over a specified time (usually 5 days at 20°C). High BOD indicates high organic pollution.
Question 5: What is a riparian buffer zone and why is it important for water quality?
- A vegetated area along waterways that filters pollutants, stabilizes banks, and provides wildlife habitat (Correct answer)
- An underwater structure that slows water flow
- A concrete channel that directs stormwater
- A fence that prevents livestock from entering waterways
Correct answer: A vegetated area along waterways that filters pollutants, stabilizes banks, and provides wildlife habitat
Riparian buffers are vegetated strips along streams and rivers that filter sediment and pollutants from runoff, stabilize streambanks, reduce erosion, moderate water temperature, and provide ecological habitat.
Question 6: What is eutrophication and what causes it?
- Excessive nutrient enrichment of water bodies causing algal blooms and oxygen depletion (Correct answer)
- The natural aging process of all water bodies over geological time
- Contamination of water with heavy metals from industrial discharge
- Salinization of freshwater bodies due to evaporation
Correct answer: Excessive nutrient enrichment of water bodies causing algal blooms and oxygen depletion
Eutrophication occurs when excess nutrients (primarily nitrogen and phosphorus) enter water bodies, stimulating excessive algae growth. When algae die and decompose, dissolved oxygen is depleted, harming aquatic life.
CES Water Quality & Watershed Management 1
What is the primary federal law governing water quality in the United States?