Water Quality & Watershed Management Flashcards

Which management practice is most effective at reducing sediment delivery from construction sites to nearby waterways?

Answer: Installing silt fences and sediment basins

Silt fences intercept sheet flow and trap sediment, while sediment basins allow larger particles to settle before water leaves the site, collectively reducing off-site sediment loading.

The Universal Soil Loss Equation (USLE) estimates annual soil loss as a function of six factors; which of these represents land management practices?

Answer: C factor (cover-management) and P factor (support practice)

The C factor accounts for vegetation cover and management effects on erosion, while the P factor reflects conservation practices like contour farming and strip cropping.

A stream classified as 'ephemeral' is characterized by which flow regime?

Answer: Flow only during and shortly after precipitation events

Ephemeral streams flow only in direct response to precipitation; they lack a connection to the water table and go dry between storm events.

Which chemical form of nitrogen is most readily taken up by algae and is therefore most responsible for promoting algal growth in surface waters?

Answer: Nitrate (NO3⁻) and ammonium (NH4⁺)

Algae preferentially assimilate dissolved inorganic nitrogen in the form of nitrate and ammonium, both of which are bioavailable and drive eutrophication in nitrogen-limited waters.

In watershed management, which approach involves purchasing development rights from landowners to permanently protect land from conversion?

Answer: Conservation easements

Conservation easements are voluntary legal agreements where landowners sell or donate development rights while retaining ownership, providing permanent land protection in a watershed.

Which drinking water treatment process is specifically designed to remove taste- and odor-causing compounds such as geosmin and methylisoborneol (MIB)?

Answer: Activated carbon adsorption (GAC or PAC)

Granular activated carbon (GAC) and powdered activated carbon (PAC) effectively adsorb geosmin and MIB, which are produced by cyanobacteria and actinomycetes and cause earthy/musty tastes.

Which naturally occurring process in lakes causes thermal stratification to break down seasonally, redistributing oxygen and nutrients throughout the water column?

Answer: Thermal turnover driven by seasonal temperature changes

Seasonal cooling (in fall) and warming (in spring) equalize surface and bottom water temperatures, eliminating density differences and allowing wind-driven mixing to overturn the water column.