Water Quality & Management Flashcards

Which parameter is most commonly used to assess the oxygen-demanding organic load in a water body?

Answer: Biochemical Oxygen Demand (BOD)

BOD measures the amount of oxygen consumed by microorganisms decomposing organic matter, directly indicating organic pollution levels.

The Clean Water Act Section 303(d) requires states to identify waters that are:

Answer: Impaired and do not meet water quality standards

Section 303(d) lists impaired waters that fail to meet water quality standards and requires development of Total Maximum Daily Loads (TMDLs).

Eutrophication in lakes is primarily caused by excess loading of which nutrients?

Answer: Nitrogen and Phosphorus

Excess nitrogen and phosphorus stimulate algal blooms that deplete oxygen and degrade aquatic habitat, causing eutrophication.

What does a Secchi disk measurement indicate in water quality monitoring?

Answer: Water clarity/transparency

A Secchi disk is lowered into water until it disappears from view; the depth at which it vanishes indicates water transparency.

Which water quality standard category protects human health through drinking water consumption and fish ingestion?

Answer: Human health criteria

Human health criteria establish maximum contaminant concentrations protective of people who drink water and consume fish from a water body.

A hydrographer notes a sudden drop in dissolved oxygen below 2 mg/L in a river reach. This condition is described as:

Answer: Hypoxic

Hypoxia refers to low dissolved oxygen conditions (typically below 2–3 mg/L) that stress or kill aquatic organisms.

Conductivity measurements in streams primarily reflect the concentration of:

Answer: Dissolved ions and salts

Electrical conductivity increases with dissolved ion concentration; high conductivity often signals elevated salinity or mineral content.