Watershed Impervious Surface Storm Water Assessment (original) (raw)
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Managing Stormwater Using Low Impact Development (LID) Techniques
As more land is covered by impervious surfaces, less rainfall infiltrates into the ground and instead becomes runoff. Too much runoff is problematic. Flooding increases, streambanks erode, and water quality is reduced. An increase of impervious area of as little 10 percent has been shown to negatively impact streams. The purpose of this publication is to explain low impact development strategies and how they can be used to improve stormwater management by reducing impacts on streams.
Evaluating the Performance of Low Impact Developments on Runoff Volume in Washington DC
2012
1. ABSTRACT The effectiveness of LID practices in reducing the stormwater runoff load in an area in the east side of the District of Columbia is evaluated. The EPA Stormwater Management Model (SWMM) is used for this evaluation. A few major simplifications have been made to make modeling of storm water possible over a large and highly heterogeneous area.
Evaluating Management Strategies for Urban Stormwater Runoff
2014
Urban stormwater runoff, a leading cause of waterway impairment, has become a focal point of urban stormwater management strategies. As urbanization increases, regulations demanding preservation of pre-development peak flow rates or runoff volumes have been implemented and low impact development (LID) is encouraged as a strategy to achieve this stormwater runoff reduction requirement. While the success of LID has been proven at the site-scale, limited watershed-scale assessment of LID has been conducted. This research explores the potential benefit of watershed-scale LID implementation on two common urban stormwater issues: degraded stream health and combined sewer overflows (CSOs). Assessment results indicate that both stream health and CSO volume reduction are possible for the 1-yr storm event if the percent impervious cover (%IC) can be reduced by 20%. Since a reduction of 20%IC is lofty in a dense urban setting, the practical extent of LID implementation in an existing urban watershed is scrutinized to determine if, based on the constraints of the built environment, LID should be realistically considered by watershed management. In a dense urban environment with typical constraints-requirement to maintain traffic flow, preexisting utility location, public vs. privately owned land, etc.-a 20% IC reduction is unreasonable using one stormwater management best management practice (BMP). To achieve maximum stormwater runoff reduction potential, an integrated, watershed-scale stormwater management approach is encouraged. The results of this
2021
Storm events and soil erosion can adversely impact flood control, soil conservation, water quality, the recreation economy, and ecosystem biodiversity in urban systems. Urban Low Impact Development practices (LIDs) can manage stormwater runoff, control soil losses, and improve water quality. The Water Erosion Prediction Project (WEPP) model has been widely applied to assess the responses of hydrology and soil losses to conservation practices in agricultural and forested areas. This research study is the first to calibrate the WEPP model to simulate streamflow discharge in the Brentwood watershed in Austin, Texas and apply the calibrated WEPP model to assess the impacts of LIDs. The costs and impacts of various LID scenarios on annual water balance, and monthly average, and daily runoff volumes, and sediment losses at hillslopes and at the watershed outlet were quantified and compared. The LID scenarios identified that native planting in Critically Eroding Areas (CEAs), native planti...
Impervious Surfaces in Urban Watersheds
2005
Urbanization causes profound changes in the hydrology of the area, specifically the timing of the runoff, the water use, runoff volume and flow rates, channel complexity, and especially pollution in receiving waters. Water quality problems increase with increasing imperviousness of the watershed. Impervious areas cause increased runoff and contaminated discharges from these areas and also contribute to receiving water contamination. Although much interest has been expressed concerning impervious areas in urban areas, actual data for the patterns of use of these surfaces is generally lacking. In this study, 125 neighborhoods were surveyed to determine the critical development characteristics representing 16 major land use areas located in the Little Shades Creek Watershed, near Birmingham, AL. The details of the impervious surfaces in these areas are described in this paper. Future project activities will include detailed stormwater modeling of each of these areas, so that the expect...
ISPRS International Journal of Geo-Information, 2021
Green Infrastructure (GI) practices are being implemented in numerous cities to tackle stormwater management issues and achieve co-benefits such as mitigating heat island effects and air pollution, as well as water augmentation, health, and economic benefits. Tucson, Arizona is a fast-growing city in the semiarid region of the southwest United States and provides a unique landscape in terms of urban hydrology and stormwater management, where stormwater is routed along the streets to the nearest ephemeral washes. Local organizations have implemented various GI practices, such as curb cuts, traffic chicanes, roof runoff harvesting, and retention basins, to capture the excess runoff and utilize it on-site. This study models the 3.31 km2 High School watershed in central Tucson using the Automated Geospatial Watershed Assessment (AGWA) tool and the Kinematic Runoff and Erosion (KINEROS2) model. Each parcel in the watershed was individually represented using the KINEROS2 Urban element to ...
Proceedings
The present work aims at quantifying the benefit of Low Impact Development (LID) practices in reducing peak runoff and runoff volume, and at comparing LID practices to conventional stormwater solutions. The hydrologic-hydraulic model used was the Storm Water Management Model (SWMM5.1). The LID practices modeled were: (i) Green roofs; and (ii) Permeable pavements. Each LID was tested independently and compared to two different conventional practices, i.e., sewer enlargement and detention pond design. Results showed that for small storm events LID practices are comparable to conventional measures, in reducing flooding. Overall, smaller storms should be included in the design process.
Modeling flood reduction effects of low impact development at a watershed scale
Journal of Environmental Management, 2016
Low impact development (LID) is a land development approach that seeks to mimic a site's predevelopment hydrology. This study is a case study that assessed flood reduction capabilities of largescale adoption of LID practices in an urban watershed in central Illinois using the Personal Computer Storm Water Management Model (PCSWMM). Two flood metrics based on runoff discharge were developed to determine action flood (43 m 3 /s) and major flood (95 m 3 /s). Four land use scenarios for urban growth were evaluated to determine the impacts of urbanization on runoff and flooding. Flood attenuation effects of porous pavement, rain barrel, and rain garden at various application levels were also evaluated as retrofitting technologies in the study watershed over a period of 30 years. Simulation results indicated that increase in urban land use from 50 to 94% between 1992 and 2030 increased average annual runoff and flood events by more than 30%, suggesting that urbanization without sound management would increase flood risks. The various implementation levels of the three LID practices resulted in 3e47% runoff reduction in the study watershed. Flood flow events that include action floods and major floods were also reduced by 0e40%, indicating that LID practices can be used to mitigate flood risk in urban watersheds. The study provides an insight into flood management with LID practices in existing urban areas.
2016
Abstract: This is the abstract section. Although recent studies have emphasized the benefits of Low Impact Development (LID), the influence of LID on impervious surface connectivity to downstream drainage has not yet been fully investigated by using quantitative measurements. Some previous studies have attempted to measure correlates between discharged stormwater volume and the directly connected impervious areas (DCIA), a fraction of the impervious area that is hydraulically connected to downstream drainage by a piped route. They found that DCIA could be a more accurate predictor of urban development impacts on stream ecosystems than is the total impervious area. This study measured the DCIA of urban watersheds in the Energy Corridor District, Houston, Texas, where rapid urbanization and increasing impervious surfaces have caused urban stream degradation during the past decades. This study primarily prioritized land use into four types based on the contribution of hypothetically im...