Stormwater Runoff Management Flashcards
7 cards from real CESSWI 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 Runoff Management flashcards as text
A grassed swale is most appropriately used in place of a curb-and-gutter system when which site condition is present?
Answer: Flat to gently sloping areas with adequate vegetative cover
Grassed swales work best on gentle slopes where vegetation can establish and flow velocities remain non-erosive, allowing infiltration and pollutant removal.
Which metric is used to evaluate whether a stormwater BMP has maintained its designed pollutant removal performance over time?
Answer: Effluent monitoring data compared to influent concentrations
Comparing influent and effluent pollutant concentrations (or loads) through monitoring data is the direct measure of a BMP's pollutant removal performance.
What is the significance of the '2-year, 24-hour storm' in stormwater management design?
Answer: It represents the storm that controls channel-forming flows and is often used for channel protection design
The 2-year, 24-hour storm approximates the channel-forming or 'bankfull' flow and is commonly used as the design event for stormwater channel protection criteria.
An inspector notices that a construction site's stabilized construction entrance is tracked out onto a public road. What is the correct immediate response?
Answer: Require immediate road sweeping or washing of tracked sediment and improvement of the entrance BMP
Tracked sediment on public roads must be removed immediately to prevent it from washing into storm drains, and the entrance BMP must be improved to prevent recurrence.
Which post-construction stormwater requirement is commonly mandated by MS4 permits to address volume and water quality goals?
Answer: On-site retention or infiltration of runoff from a specified design storm
MS4 post-construction programs typically require retention or treatment of the water quality volume on-site, often the 1-inch storm or 90th percentile event, to meet volume and pollutant load reduction goals.
What does the term 'hydromodification' refer to in stormwater management?
Answer: Changes in watershed hydrology caused by land development that alter flow frequency, duration, and magnitude
Hydromodification refers to alterations in the hydrologic regime of streams resulting from land development, including changes in peak flows, flow duration, and total runoff volume.
Which inspection finding would indicate that a dry extended detention pond is NOT functioning as designed?
Answer: Permanent pool of water remains in the pond bottom weeks after the last storm
A dry extended detention pond is designed to drain completely between storms; a permanent pool indicates a clogged outlet, high water table, or improper grading that prevents full drainage.