Urbanization causes various environmental issues including water pollution, air pollution, and solid waste. Urbanization of watersheds has a profound influence on the quality of stormwater runoff. The quality of stormwater runoff is highly associated with land use. This study analyzed the exceedance frequency of stormwater quality in five watersheds of Denton over eleven years and also analyzed the relationship between stormwater quality and land use/cover of each watershed. The results showed that the most of the water quality parameters that were examined in the Lower Pecan watershed exceeded their threshold most frequently. The higher frequency of exceedance in this watershed can be attributed to the wastewater treatment plant and landfill site. Total suspended solids and turbidity were frequently exceeded in Hickory and Clear Creek watersheds. Conductivity was found to have highest percentage of exceedance in Upper Pecan and Cooper watersheds. Thus, rural watersheds were related with higher exceedance of TSS and turbidity whereas urban watersheds were related with higher exceedance of conductivity.

Rain gardens are low impact developments designed to mitigate a suite of issues associated with urban stormwater runoff. The site for this study was a Denton City rain garden at the Denton Waste Water Treatment Plant. Nitrogen and phosphorus removal was examined in light of two overflow events comprised of partially treated wastewater from an upslope anaerobic digester pond. Nitrate removal efficiency was examined across differing dry spell intervals of 5, 8, and 12 d, displaying a moderate negative correlation (r2 = 0.59). Continued phosphorus removal capacity was assessed, showing phosphorus removal in cases where P was in excess of 0.8 mg/L, reflecting an equilibrium phosphorus concentration. A high expanded shale component in the soil media (25%) was likely a factor in the continued removal of phosphorus. Overall the rain garden proved to be a large source of nitrate (+425%) and total nitrogen (+61%) by mass. The study showed that while the rain garden intercepted a large volume of partially treated wastewater during the overflow events, preventing it from reaching a nearby creek, the mitigation of an acute event has extended to a chronic one as nitrogen is gradually processed and flushed from the system as nitrate.

In order to better understand runoff characteristics from natural gas well sites in north central Texas, the City of Denton, with assistance through an EPA funded 104b3 Water Quality Cooperative Agreement, monitored storm water runoff from local natural gas well sites. Storm water runoff was found to contain high concentrations of total suspended solids (TSS). Observed TSS concentrations resulted in sediment loading rates that are similar to those observed from typical construction activities. Petroleum hydrocarbons, in contrast, were rarely detected in runoff samples. Heavy metals were detected in concentrations similar to those observed in typical urban runoff. However, the concentrations observed at the gas well sites were higher than those measured at nearby reference sites. Storm water runoff data collected from these sites were used to evaluate the effectiveness of the water erosion prediction project (WEPP) model for predicting runoff and sediment from these sites. Runoff and sediment predictions were adequate; however, rainfall simulation experiments were used to further characterize the portion of the site where drilling and extraction operations are performed, referred to as the "pad site." These experiments were used to develop specific pad site erosion parameters for the WEPP model. Finally, version 2 of the revised universal soil loss equation (RUSLE 2.0) was used to evaluate the efficiency of best management practices (BMPs) for natural gas well sites. BMP efficiency ratings, which ranged from 52 to 93%, were also evaluated in the context of site management goals and implementation cost, demonstrating a practical approach for managing soil loss and understanding the importance of selecting appropriate site-specific BMPs.

Modern cities are often perceived as the antithesis of nature; the built environment is understood as the transformation of raw and untamed nature into a rationalized human landscape. However, a variety of scholars since the nineteenth century have noted the persistence of nature in cities, not only in providing essential services but also resisting human control. Most recently, urban geographers and environmental historians have argued that processes of urbanization do not entail the replacement of natural with artificial environments, but are more accurately understood as a reconfiguration of human/nature relations. In this dissertation, I employ this relational perspective to study a specific form of urban nature: stormwater flows. Urban drainage or stormwater management activities in US cities are a vivid example of the tensions between nature, society, and technology. In this study, I present a comparative case study of two US cities--Austin, Texas and Seattle, Washington--where stormwater issues have been a central focus of public debate over the last four decades. Using textual analysis, in-depth interviews, and experiential research methods, I argue that stormwater management practices involve not only the rational management of technological networks but also implicate a wide range of seemingly unrelated issues, such as local governance, environmental protection, land use decisionmaking, community development, aesthetics, and social equity. To describe the relational implications of urban nature, I present a framework of ecological politics to characterize drainage activities as rational, populist, or civic. I argue that the latter form of politics has the greatest potential to relieve the tensions between urban residents and their material surroundings by embracing a systems perspective of human/nonhuman relations and engaging local residents in the hands-on management of environmental flows. It is through the development of deliberative and grounded forms of civic politics that urban residents can forge new relationships between technology and nature, and in the process, understand their place in the world. / text