Hydrology & Watershed Management Flashcards
7 cards from real CSM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Hydrology & Watershed Management flashcards as text
Which method is most appropriate for estimating peak discharge from a small urban watershed (< 200 acres) for a short-duration, high-intensity storm?
Answer: The Rational Method (Q = CiA)
The Rational Method is well-suited for small urban watersheds where simplicity is needed and the assumptions of uniform rainfall and steady-state runoff are reasonably met.
Evapotranspiration (ET) is typically highest in watersheds that have:
Answer: Dense vegetation, warm temperatures, and ample soil moisture
ET requires energy (solar radiation and heat), available water, and leaf area to transpire moisture; dense vegetated watersheds with warm climates and moist soils maximize ET losses.
Stream order classification in the Strahler system defines a third-order stream as:
Answer: A stream formed by the confluence of two second-order streams
In the Strahler ordering system, two streams of equal order joining creates a stream of the next higher order; therefore, two second-order streams joining creates a third-order stream.
Which hydrologic term describes precipitation that is captured by vegetation and never reaches the ground surface?
Answer: Interception
Interception is the process by which precipitation is caught and held by plant canopy, from which it evaporates before reaching the soil surface.
A frequency analysis of annual peak streamflow data is used to:
Answer: Estimate the probability of occurrence of floods of various magnitudes
Flood frequency analysis fits statistical distributions to annual peak flow records to estimate the probability (return period) associated with flood events of various magnitudes.
What is the primary hydrologic impact of replacing natural land cover with impervious surfaces on water quality?
Answer: Increased stormwater runoff volume carrying pollutants accumulated on pavement
Impervious surfaces prevent infiltration, increasing both runoff volume and velocity while washing accumulated pollutants such as oils, metals, and nutrients into waterways.
The 'first flush' phenomenon in urban stormwater hydrology refers to:
Answer: The disproportionate concentration of pollutants in the early portion of a runoff event
During the first flush, pollutants accumulated on impervious surfaces between storms are mobilized in high concentrations in the initial runoff, often representing the majority of the event pollutant load.