Sustainable water resources in intricate urban environments
Date
2020
Authors
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Publisher
University of Delaware
Abstract
This dissertation analyzes the urban water resources in northwestern Delaware from hydrology and water use perspectives. Three journal articles examine stream response to historical climate extremes at urban environments, develop hourly streamflow simulation at the local scale, and analyze water use determinant factors. The first article studies the impacts of historical extreme climates on watersheds of White Clay Creek and upper Christina River with today’s land cover. Both watersheds are vulnerable to hazards of drought and flooding. Meteorology inputs of extreme wet (1996) and dry years (1964–65) were selected to simulate daily streamflow of historical climates on the present land surface using the Soil and Water Assessment Tool (SWAT). SWAT is a physically-based hydrologic model rooted in a water balance approach that has been used effectively to examine problems in non-urban and urban environments. The historical wet year simulation revealed the baseflow decrease in the upper Christina River in comparison to 1996 gage records. The dry year simulation indicate urban development over the last 55 years leads to lower baseflow and greater streamflow variability in both watersheds. ☐ The second article delivers an unprecedented study of hourly streamflow simulation using the SWAT model for the same two watersheds in northwestern Delaware. There is lack of development of the hourly SWAT model in the northeast US with its humid continental to subtropical climate conditions and intensive urbanization which is subject to high flood risk. Calibration of the hourly SWAT model is a critical step to reproduce the seasonality of streamflow and achieve meaningful result. Careful examination of the influence of the model parameters on hourly simulated streamflow allowed the identification of sensitive parameters to accurately reproduce the seasonality of discharge at an hourly time step. In this study, the model parameters that control runoff travel time such as the Manning roughness required considerable adjustment to accurately simulated the peak flow dynamics. With careful model calibration, we found hourly SWAT is a reliable modelling tool for local level watersheds. ☐ The third article uses statistical and GIS models to analyze single-family water use at census block level in Newark, Delaware. Variables are gathered from three data sources: census, structure detail (building information), and landuse. The statistical results show water consumption is best explained by number of housing units or total water use fixture with 84 percent accuracy. The spatial autocorrelation analysis indicates the water use spatial pattern is rather disperse across the city of Newark with a few high water use clusters in northeast portion of the city and low water use clusters in the city center and western part of the city. ☐ Together, these three articles examine the impacts of urban development and climate extreme on urban water resources. An improved understanding of the hydrologic response to urbanization and climate change along with water use in urban environment will assist with sustainable water resources management and planning.
Description
Keywords
Urban hydrology, Urban water use, Sustainable water resources, Delaware, Soil and Water Assessment Tool, Flood risk