Graduation Semester and Year




Document Type


Degree Name

Master of Landscape Architecture


Landscape Architecture

First Advisor

Taner R. Ozdil


Recognizing environmental problems associated with sprawl, North Texas communities are looking at options for future growth. Higher density mixed-used developments (MXDs) are being considered as an alternative to the continuation of current trends and adopted plans, yet little is known how they impact the region environmentally (Vision North Texas, 2008). More specifically, it is not clear how these developments perform in regard to stormwater runoff and water pollution. This research evaluates the stormwater runoff and water pollution of two mixed-use developments (MXDs) in order to understand their environmental role in the future of North Texas. The research question in this study is two-fold. First, how the varying designs, planning and land management characteristics of two MXDs impact stormwater runoff and pollution. Second, is the Soil and Water Assessment Tool (SWAT) an effective tool to measure such an impact? Two local mixed-use developments, Southlake Town Square and Addison Circle, are chosen based on urban form typology, common design elements and a similar mix of land uses (Ozdil, et al.; 2009; New Urban News, 2003). The study utilizes Geographic Information Systems (GIS), site reconnaissance, and the Soil and Water Assessment Tool (SWAT) to evaluate stormwater runoff and pollution and its relation to land use density and the imperviousness of exterior design elements. Orthophotographic interpretation, using GIS, is used primarily to inventory, categorize and calculate design element areas and permeability. The inventory is followed by site inspection to: (1) assess the mitigation potential of exterior design elements, and (2) clarify ambiguities resulting from orthophotograph interpretation. Results of the hydrologic modeling are evaluated in relation to land use density and the imperviousness of exterior design elements. They are further validated through a comparison of observed data reported in regional and national stormwater runoff studies. Based on the level of imperviousness, the land management scenarios and the site design, results of the two cases studies indicate higher concentrations of nitrate (NO3) in the surface runoff compared to commercial, industrial and residential land uses reported in other urban stormwater studies. Yearly average organic nitrogen (N) and soluble phosphorus (P) concentrations varied when compared to tested event mean concentrations of different land uses, but were lower than residential sites tested. This suggests that higher density urban areas, with significant levels of imperviousness, can produce lower amounts of pollutants in stormwater runoff than lower density residential developments. Findings from the two case studies covered in this research lead to the conclusion that design, land-use density, and land management practices all affect the stormwater runoff performance in mixed-use developments. Careful planning and design combined with stormwater best management practices can help to improve the water quality and quantity of stormwater runoff. This research also illustrates that the Soil and Water Assessment Tool (SWAT) provided a reasonable assessment for stormwater runoff performance in higher density urban areas. With further research, SWAT can be a valuable tool for landscape architects in the pre-construction planning and design phases of development.


Architecture | Landscape Architecture


Degree granted by The University of Texas at Arlington