Stormwater Management & Drainage Engineering Flashcards
7 cards from real CME practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Stormwater Management & Drainage Engineering flashcards as text
A Stormwater Pollution Prevention Plan (SWPPP) is required under which regulatory framework for construction sites disturbing one or more acres?
Answer: NPDES Construction General Permit
The NPDES Construction General Permit requires construction sites disturbing one or more acres to develop and implement a SWPPP that identifies potential pollutant sources and describes Best Management Practices (BMPs) to reduce pollutants in stormwater discharges.
A bioswale is best described as:
Answer: A vegetated channel designed to slow stormwater runoff and filter pollutants through plants and soil
A bioswale is a landscaped channel with dense vegetation that slows stormwater runoff, promotes infiltration, and removes pollutants through filtration, adsorption, and biological uptake.
In the Rational Method, which factor primarily reflects the land use and surface characteristics of a drainage area?
Answer: Runoff coefficient (C)
The runoff coefficient (C) represents the fraction of rainfall that becomes surface runoff and varies by land use — for example, C ≈ 0.90 for impervious pavement versus C ≈ 0.25 for lawns with sandy soil.
An MS4 (Municipal Separate Storm Sewer System) permit under Phase II NPDES regulations applies to municipalities with populations below:
Answer: 100,000
Phase II MS4 regulations extended NPDES permit requirements to regulated small MS4s serving populations under 100,000, requiring six minimum control measures to reduce stormwater pollutants.
The 'first flush' phenomenon in urban stormwater refers to:
Answer: The disproportionately high concentration of pollutants in the initial portion of a storm runoff event
The first flush effect describes how pollutants accumulated on impervious surfaces between storms are washed off in high concentrations during the early part of a runoff event, making initial runoff volumes particularly important to treat for water quality.
A storm hydrograph depicts the relationship between:
Answer: Discharge rate (flow) over time at a specific point in a watershed
A storm hydrograph is a plot of discharge rate versus time at a measurement point, showing how streamflow rises to a peak and recedes in response to a rainfall event.
Low Impact Development (LID) is a stormwater management approach that primarily aims to:
Answer: Replicate the pre-development hydrologic condition of a site using distributed, small-scale controls
LID seeks to maintain or replicate pre-development hydrology by using distributed practices such as bioretention cells, rain gardens, permeable pavement, and green roofs to manage stormwater at the source.