Stormwater engineers have always been involved in capturing rainwater and transferring it offsite as fast as possible. This approach managed to the construction of a vast operation of large, centralized processing facilities managing millions of gallons of stormwater annually – a very efficient, but not very environmentally-minded solution.
There has been a shift in the way we approach this problem. After decades of development that prioritized efficiency and convenience over sustainability, there is now a significant shift. Green Stormwater Infrastructure (GSI), a subset of low impact development solutions, is a method of stormwater management that mimics and/or restores the natural water cycle.
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GSI aims to reduce stormwater flow to large municipal systems, and the flooding and overflows that can be caused by their failures. Stormwater engineers trade pipe flow rates for soil/clay infiltration rates, and design methods that keep rainwater at the site, where it lands. This allows them to return rainfall to the natural environment after it has been cleaned.
This shift has a side effect: not all landowners and developers understand the benefits of green stormwater infrastructure. These systems' success depends on their design, maintenance, and education. To support architects and engineers designing them, site owners and developers need to understand and appreciate the value of these systems.
Low-impact development techniques have a positive impact on the environment, according to evidence ( GSI performance study). GSI encourages the use of infiltration and reduces hardscapes.
This results in less runoff from the surface, more pollution, lower erosion, and less flooding. Infiltration recharges the groundwater table and reduces urban runoff's impact on freshwater bodies (lakes, streams, oceans) and saltwater bodies. It also recharges base flows essential for fish and wildlife.