Water Quality & Management Flashcards

A Total Maximum Daily Load (TMDL) allocates pollutant loads among which sources?

Answer: Point sources, nonpoint sources, and a margin of safety

A TMDL divides the allowable pollutant load among wasteload allocations (point sources), load allocations (nonpoint sources), and a margin of safety.

Which sampling method is preferred for collecting water quality samples to represent average stream conditions at a cross-section?

Answer: Depth-integrated sampling across the stream width

Depth-integrated samples collected at multiple verticals across the cross-section provide a flow-weighted composite representative of total stream conditions.

The US EPA's National Pollutant Discharge Elimination System (NPDES) regulates which type of water pollution source?

Answer: Point source discharges to navigable waters

NPDES permits regulate point source discharges—those from a discrete conveyance such as a pipe or ditch—to waters of the US.

Which process most effectively removes phosphorus from stormwater in a constructed wetland?

Answer: Sedimentation and biological uptake by vegetation

Phosphorus is removed in wetlands primarily through particle settling and assimilation by aquatic plants and algae.

A stream's assimilative capacity refers to its ability to:

Answer: Receive and break down pollutants without violating water quality standards

Assimilative capacity is the amount of waste a water body can absorb through natural processes without exceeding water quality criteria.

Which parameter is the best indicator of fecal contamination from warm-blooded animals in recreational waters?

Answer: Escherichia coli (E. coli) or Enterococcus bacteria

E. coli and Enterococcus are fecal indicator bacteria used by the EPA to assess microbial water quality for recreational standards.

When collecting water samples for volatile organic compound (VOC) analysis, the sample bottle should be:

Answer: Filled completely with no headspace and kept chilled

VOCs escape to headspace readily, so bottles must be completely filled, zero-headspace preserved, and chilled to minimize volatilization losses.