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Tailoring Green Infrastructure Implementation Scenarios based on Stormwater Management Objectives
Citation:
Lee, J. AND C. Nietch. Tailoring Green Infrastructure Implementation Scenarios based on Stormwater Management Objectives. Presented at World Environment and Water Resource Conference 2016, West Palm Beach, FL, March 22 - 26, 2016.
Impact/Purpose:
We have developed modeling approaches using the Stormwater Management Model (SWMM) to study the consequences of achieving specific GI objectives, some of which may be unintended. We demonstrate our model methods for tailoring a GI implementation scenario in a well monitored suburban headwatershed outside of Cincinnati, OH.
Description:
Green infrastructure (GI) refers to stormwater management practices that mimic nature by soaking up, storing, and controlling onsite. GI practices can contribute reckonable benefits towards meeting stormwater management objectives, such as runoff peak shaving, volume reduction, flood control, pollutant removal, and/or rainwater reuse. However, there may be unexpected consequences of achieving specific objectives pending the chosen GI alternative. For example, if rooftop runoff is directed through vegetated strips/swales, the runoff peak and volume contributed by the rooftop area should be decreased, but the stormwater ultimately discharged may be enriched from natural or artificially applied soil nutrients (i.e., fertilizers). If elevated stream nutrient concentrations are an issue, this type of GI implementation may actually exacerbate the problem. Another example might be a realized increase in localized flooding, resulting in basement inundation when GI is situated near housing foundations. This type of unintended consequence may arise where not-so-intense, but sizable, storms have a long duration. The pervious area reaches hydrologic saturation and all rainfall converts to runoff, GI effects are nullified, and engineered conveyance is under designed to handle the higher risk of local inundation. We have developed modeling approaches using the Stormwater Management Model (SWMM) to study these effects. Stormwater management objectives and how those objectives are ultimately realized are very site-specific. Even a similar objective may result in very different GI prescriptions pending the site-specific physiogeography. Here we demonstrate our model methods for tailoring a GI implementation scenario in a well monitored suburban headwatershed outside of Cincinnati, OH.
