Doctoral Dissertation Research: Exurban Land-Use Change, Watershed Management, and Surface-Water Quality

城市快速扩张是美国常见的城市化形式，但其环境影响受到的关注有限。 从空间的角度来看，扩张开始于郊区边缘，通常是通过取代农业用地，但对郊区和农业环境之间地表水质量的差异知之甚少。 许多社会制度影响着扩张的环境影响，其中之一就是流域管理。 大量资源用于地方流域管理，但其有效性仍不确定。 因此，本博士论文研究改进项目旨在澄清郊区和农业环境之间的地表水质量差异，以及参与式和分散式流域管理（而不是以国家为中心的管理）对郊区和农业地表水质量的影响程度。 这项研究将采用定量生物物理和定性社会数据和方法。 对俄亥俄州克利夫兰大都市区82个小流域的普通最小二乘回归分析将以卫星图像、水生生物评估和其他空间数据为基础，从而为量化水生生物多样性与土地利用之间的关系奠定基础。 一个密集的，基于历史的四个流域的比较案例研究将分析流域管理在水质中发挥的作用。 该项目中使用的数据包括回归结果、额外的高分辨率空间数据、对俄亥俄州流域组的调查、与关键流域利益相关者的半结构化访谈以及评估利益相关者主观性的排名和因素分析。 工作假设是：（1）农业土地利用通常比郊区土地利用促进相对更大的水生生物多样性，尽管由于特定的当地生物物理和社会因素而产生显著的变化;（2）参与式和分散式流域管理比更集中的管理促进更大的水生生物多样性。城市增长。 城市扩张是一个具有国家经济和环境重要性的问题，它加剧了这一难题。 预计研究结果将有助于澄清城市扩张对地表水质量的影响，为目前关于城市持续增长和环境质量的辩论提供更多的科学证据。 这项研究还将阐明哪些影响水质的特定因素最适合流域管理做法或其他政策举措，从而帮助确定在哪里最好地分配有限的流域管理资源。 作为博士论文研究改进补助金，该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。

Rapid urban expansion is a form of urbanization common in the United States, yet its environmental impacts have received limited attention. From a spatial perspective, expansion begins in the exurban fringe, often by replacing agricultural land, yet differences in surface-water quality between exurban and agricultural environments are poorly understood. Numerous social institutions influence expansion's environmental impacts, one being watershed management. Significant resources are devoted to local watershed management, yet uncertainty remains concerning its effectiveness. This Doctoral Dissertation Research Improvement project therefore aims to clarify surface-water quality differences between exurban and agricultural environments and the degree to which participatory and decentered watershed management, as opposed to state-centered management, influences exurban and agricultural surface water quality. The study will employ both quantitative biophysical and qualitative social data and methods. An ordinary least-squares regression analysis for 82 small watersheds in the Cleveland, Ohio, metropolitan area will be based on satellite imagery, aquatic bioassessments, and other spatial data, thereby forming a basis for quantifying relationships between aquatic biodiversity and land use. An intensive, historically based comparative case study of four watersheds will analyze the role watershed management plays in water quality. Data to be used in the project include the regression findings, additional high-resolution spatial data, a survey of Ohio watersheds groups, semi-structured interviews with key watershed stakeholders, and rankings and factor analyses evaluating stakeholder subjectivity. Working hypotheses are that (1) agricultural land use generally fosters relatively greater aquatic biodiversity than exurban land use, although notable variation results from particular local biophysical and social factors, and (2) participatory and decentered watershed management fosters greater aquatic biodiversity than more centralized management.Many Americans want the best possible environmental quality, but they also desire continued economic, population, and urban growth. Urban expansion, an issue of national economic and environmental importance, exemplifies this conundrum. Research findings are expected to help clarify the impacts of urban expansion on surface-water quality, offering additional scientific evidence to the ongoing debate concerning continued urban growth and environmental quality. This study also will shed light on which particular factors affecting water quality are most amenable to watershed management practices or other policy initiatives, thereby helping to determine where best to allocate limited watershed management resources. As a Doctoral Dissertation Research Improvement grant, this award will also provide support to enable a promising student to establish a strong independent research career.