Module 10: Stormwater and its Management exam questions fully solved & updated 2024

Stormwater water generated from a rainstorm or snowstorm that makes its way to a nearby waterbody shortly after precipitation reaches the surface. 5 statements about stormwater a. generated during heavy precipitation events b. larger watershed take a longer time to fnnel stormwater to waterbodies than small ones. c. some watersheds and drainage systems such as hilly or urban environments efficiently and quickly transport stormwater to water bodies. d. most stormwater moves across the surface. however some can move through subsurface before reaching a water body e. stormwater can be generated in a variety of environments. However, it is an acute issue in cities because of impervious surfaces--> reducing ET and soil/groundwater infiltration. Impacts of stormwater 1. runoff can impact aquatic ecosystems by dgrading rivers/streams from urban runoff 2. threaten human health 3. increase chances of flooding in an urban development 4. managing stormwater is expensive How does stormwater impact water bodies? alter water quality, flow regimes and energy inputs Most common water quality problems caused by stormwater metals, pathogens/bacteria, sediment, nutrients. oxygen depletion, pH, temperature, habitat alteration, pesticides, salinity/chlorine, PCBs. Although 1972 CWA helped reduced nations water quality problems, why has urban stormwater been recorgnized as an unsolved problem? a. urban stormwater comes from virtually everywhere, not geographically concentrated. b. production is episodic and fluctuations are difficult to predict. Efforts that have been made lead to a series of other problems in water bodies c. transports a variety of chemicals, nutrients, bacteria, metals, trash, heat energy d. expensive from storm drain installations to maintenance to monitoring flows and quality. What are some pollutants that stormwater carries sediment and floatables, pesticides/herbicides, organic materials, metals, oil/grease, bacteria/viruses, nitrogen/phosphorus A National Pollution Discharge Elimination System (NPEDS) a program that dischargers were required to participate which they are required to obtain permits to discharge. Section 402 (p) broadens the scope of the NPDES for a range of activities that were barely regulated. permits are obtained from construction sites >1acre, industrial facilities, landfills, concentrated feelots, MS4s. what are 5 framework problems of stormwater? 1. CWA focuses on pollutants, not volume of discharge. Although water quality is high, volume of stormwater can impact receiving water bodies. 2. governing sotrmwater left to disharger's discreation. 3. EPA has not exercised its authority to limit/ban products that contribute to pollution 4. too expensive to cope with 10,000 point source facilities discharging stormwater 5. most agricultural activity does not require NPDES Steps to developing and implementing a sound stormwater management plan a. work with stakeholders to identify problems and define outcome. b. determine financial,legal, political and social constraints to possible solutions. c. formulate a technical approach d. using best management practice. Either build structures and systems to store and partially treat stormwater or educate public to reduce problem at its source. e. Physical aspects of improving water quality such as sedimentation, floatation, filtration, infiltration, adsorption, biological uptake f. construct specific structural features including wetlands, roadside swales, infiltration trenches, storage vaults green infrastructure and stormwater use of green infrastructure to mimic nature's way of absorption. examples include rainwater harvesting and storing, rain gardens, porous pavements, green streets (promotes infiltration), green roofs that feature grass, soil, and shallow rooted plants--> reduce and purify runoff. Baseflow Streamflow coming from groundwater seepage into a stream or river. It can appear days, weeks, months after precipitation event. Interflow Water that percolates just below the land surface and moves in the same direction as overland flow