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

快速的城市扩张是美国常见的一种城市化形式，但其对环境的影响却很少受到关注。从空间角度来看，扩张始于远郊边缘，通常是通过取代农业用地，但人们对远郊和农业环境之间地表水质量的差异知之甚少。许多社会机构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城郊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对城郊和农业地表水质量的影响程度，而不是以国家为中心的管理。该研究将采用定量的生物物理和定性的社会数据和方法。基于卫星图像、水生生物评价和其他空间数据，对俄亥俄州克利夫兰市区82个小流域进行了普通最小二乘回归分析，从而为水生生物多样性与土地利用之间的定量关系奠定了基础。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所起的作用。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、对俄亥俄州流域群体的调查、对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体性的排名和因素分析。工作假设是：(1)农业用地通常比城郊用地促进相对更大的水生生物多样性，尽管特定的当地生物物理和社会因素导致显着差异；(2)参与式和分散式流域管理比集中式管理更能促进水生生物多样性。许多美国人想要尽可能好的环境质量，但他们也希望经济、人口和城市持续增长。城市扩张是一个事关国家经济和环境的重要问题，它体现了这一难题。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，为正在进行的关于持续城市增长和环境质量的辩论提供额外的科学证据。这项研究还将阐明影响水质的哪些特定因素最适合于流域管理做法或其他政策倡议，从而有助于确定在哪些地方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，该奖项还将为有前途的学生提供支持，使他们能够建立强大的独立研究事业。

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.