Assessing the Effects of Climate Change on Water Quantity and Quality in an Urban Watershed Using a Calibrated Stormwater Model

Abstract

Assessing climate change (CC) impacts on urban watersheds is difficult due to differences in model spatial and temporal scales, making prediction of hydrologic restoration a challenge. A methodology was developed using an autocalibration tool to calibrate a previously developed Storm Water Management Model (SWMM) of Difficult Run in Fairfax, Virginia. Calibration was assisted by use of multi-objective optimization. Results showed a good agreement between simulated and observed data. Simulations of CC for the 2041-2068 period were developed using dynamically downscaled North American Regional CC Assessment Program models. Washoff loads were used to simulate water quality, and a method was developed to estimate treatment performed in stormwater control measures (SCMs) to assess water quality impacts from CC. CC simulations indicated that annual runoff volume would increase by 6.5%, while total suspended solids, total nitrogen, and total phosphorus would increase by 7.6%, 7.1%, and 8.1%, respectively. The simulations also indicated that within season variability would increase by a larger percentage. Treatment practices (e.g., bioswale) that were intended to mitigate the negative effects of urban development will need to deal with additional runoff volumes and nutrient loads from CC to achieve the required water quality goals.

Impaired Water Hazard Zones: Mapping Intersecting Environmental Health Vulnerabilities and Polluter Disproportionality

“…First, surface water CAWMHS only includes industrial surface water toxic releases from the U.S. EPA RSEI database. In addition, surface water CAWMHS does not account for the fate and transport of pollutants as found in a number of hydrological analyses used for assessing total maximum daily loads (TMDL) for U.S. waterways [24][25][26][27][28][29]. Accordingly, questions remain regarding the unequal spatial distribution of a broader set of point and non-point-sources (NPS) in the region.…”

Water supply and runoff capture reliability curves for hypothetical rainwater harvesting systems for locations across the U.S. for historical and projected climate conditions

“…Projections for rainfall across the U.S. from the North American Regional CC assessment program (NARCCAP) [2] were used as input data for historical and projected conditions. The historical hourly observation rainfall data from 1971–1998 were obtained from National Climate Data Center (NCDC) ( https://www.ncdc.noaa.gov/ ); this data was used for bias correction of NARCCAP historical and projected climate simulations for the same locations in a procedure described in [3] . NARCCAP provides model output at three-hourly intervals.…”

“…Biases that could affect the hydrological model simulations were corrected using modified version of the equiratio cumulative distribution function matching method [9] . The reader is referred to [3] for more detail on the bias correction method. NARCCAP provides model output at three-hourly intervals, which is not sufficient temporal scale for precipitation.…”

Effect of Sediment Accumulation on Best Management Practice (BMP) Stormwater Runoff Volume Reduction Performance for Roadways

“…Since a lot of information is missing from reported sites to make this comparison effective, some studies used numerical simulations to evaluate the effect of each parameter on BMP system performance. Some of the numerical simulation studies include the Hydrological Simulation Program-Fortran (HSPF) [3,14], the Soil and Water Assessment Tool (SWAT) [15,16], the Long-Term Hydrologic Impact Assessment-Low Impact Development (L-THIA-LID) [17][18][19], and the Storm Water Management Model (SWMM) [20][21][22][23][24]. This paper seeks to explore BMP performance deterioration due to sediment accumulation using field and numerical simulations.…”