Title: ET Influence on Urban Stormwater Runoff Estimation
Abstract: Evapotranspiration (ET) generally receives little attention in urban stormwater modeling, which often assumes a constant ET at monthly or seasonal intervals for an entire city area. However, unlike natural environments uniformly covered by pervious areas that accumulate and store rainwater for ET and infiltration, using the constant ET value to estimate runoff for the much more heterogeneous urban surfaces with checkered impervious areas and vegetation covers may lead to inaccurate estimates of ET and thus inaccuracies in long-term runoff volume estimates. And as new stormwater management approaches implementing green infrastructure and urban planning philosophies promoting green spaces advance, the impact of vegetation and ET on urban hydrology is increasing. To investigate this uncertainty related to ET, we test how finer consideration of ET in terms of spatial and temporal variations influence urban runoff estimation both in amount and time. We hypothesize that diverse types of land use/cover areas generate different impacts on ET and then the stormwater runoff due to their difference in storage capacity and ET rates. To test the hypothesis, the case study selected is a drainage catchment in Murray, Utah, located in the center of the Salt Lake City metropolitan area. EPA SWMM is employed in this study to simulate the water budget and estimate the runoff. The Eddy Covariance, Hargreaves method, and Penman Monteith equation are adopted to estimate the ET for different vegetation species and applied to different subcatchments in the city. The ET estimation results are imported into the SWMM model and used to test the influence of spatial and temporal variation of ET on the city's runoff reduction.
Publication Year: 2013
Publication Date: 2013-05-28
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 3
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