道路和交通是城市化的重要内容,但是很少研究它们与流域地表水质量的空间关联。在这项研究中,三个城市化指标在空间上不同的关联,包括道路密度,交通密度,和城市土地的百分比,有二十个水质指标,包括溶解氧(DO),比电导(SC),溶解固体(DS),悬浮固体(SS),生化需氧量(BOD),溶解的营养素,溶解的离子,重金属,和大肠杆菌,横跨佐治亚州北部的流域,美国,已经通过传统的统计方法进行了检查,普通最小二乘回归(OLS),和空间统计方法,地理加权回归(GWR)。OLS的结果表明,城市化指标都与大多数研究的水污染物具有显著的正相关关系,表明与佐治亚州北部城市化有关的人类活动对水污染有很大贡献。相比之下,GWR结果表明,受城市化水平影响的流域之间的关联各不相同。在每个城市化指标和每个研究的水污染物之间发现了显着的正相关,但不是在所有流域。悬浮固体的协会,氮素养分,与所有三个城市化指标的大肠杆菌在城市化程度较低的流域中更为明显,而溶解离子的缔合,BOD,正磷酸盐(PO4)与道路密度和交通密度相比,在城市化程度较高的流域中,具有城市土地的正磷酸盐(PO4)更为明显,这表明,与城市化地区的其他活动相比,与道路和交通相关的人类活动对这些水污染物的贡献更大。作为一项试点研究,探讨地表水质量与道路和交通的关联如何以及为什么在不同城市化水平的流域发生变化,其研究结果表明,流域管理政策,土地利用规划,交通规划应根据当地重要的水污染物及其相关的城市化指标在当地进行调整。
Roads and traffic are important elements of urbanization, but their spatial associations with surface water quality in watersheds have been seldom studied. In this study, the spatially varying associations of three urbanization indicators, including road density, traffic density, and percentages of urban land, with twenty water quality indicators, including dissolved oxygen (DO), specific conductance (SC), dissolved solids (DS), suspended solids (SS), biochemical oxygen demand (BOD), dissolved nutrients, dissolved ions, heavy metals, and coliform bacteria, across the watersheds in the northern part of the state of Georgia, USA, have been examined by a conventional statistical method, ordinary least squares regression (OLS), and a spatial statistical method, geographically weighted regression (GWR). The results from OLS show that the urbanization indicators all have significant positive associations with the majority of the studied water pollutants, indicating that water pollution is significantly contributed by human activities related to urbanization in northern Georgia. In contrast, GWR results show that the associations vary across the watersheds affected by their urbanization levels. Significant positive associations are found between each urbanization indicator and each of the studied water pollutants, but not in all watersheds. The associations of suspended solids, nitrogen nutrients, and coliform bacteria with all three urbanization indicators are more significant in less-urbanized watersheds, while the associations of dissolved ions, BOD, and orthophosphate (PO4) with road density and traffic density are more significant than those with urban land in more-urbanized watersheds, indicating that those water pollutants are more contributed by human activities associated with roads and traffic than other activities in more-urbanized areas. As a pilot study to explore how and why the associations of surface water quality with roads and traffic change across watersheds with different urbanization levels, its findings suggest that the policies of watershed management, land-use planning, and transportation planning should be tailored in local areas based on the locally important water pollutants and their associated urbanization indicators.