Watershed protection, and associated in situ water quality improvements, has received considerable attention as a means for mitigating health risks and avoiding expenditures at drinking water treatment plants (DWTPs). This study reviews the literature linking source water quality to DWTP expenditures. For each study, we report information on the modeling approach, data structure, definition of treatment costs and water quality, and statistical methods. We then extract elasticities indicating the percentage change in drinking water treatment costs resulting from a 1% change in water quality. Forty-six elasticities are obtained for various water quality parameters, such as turbidity, total organic carbon (TOC), nitrogen, sediment loading, and phosphorus loading. An additional 29 elasticities are obtained for land use classification (e.g., forest, agricultural, urban), which often proxy source water quality. Findings indicate relatively large ranges in the estimated elasticities of most parameters and land use classifications. However, average elasticities are smaller and ranges typically narrower for studies that incorporated control variables consistent with economic theory in their models. We discuss the implications of these findings for a DWTP's incentive to engage in source water protection and highlight gaps in the literature.

中文翻译：

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原水水质对饮用水处理成本的影响：实证文献综述与综合

流域保护以及相关的原位水质改善，作为减轻健康风险和避免饮用水处理厂 (DWTP) 支出的一种手段，已受到相当多的关注。本研究回顾了将源水水质与 DWTP 支出联系起来的文献。对于每项研究，我们都会报告有关建模方法、数据结构、处理成本和水质的定义以及统计方法的信息。然后我们提取弹性，表明水质变化 1% 导致饮用水处理成本的百分比变化。对于各种水质参数，如浊度、总有机碳 (TOC)、氮、沉积物负荷和磷负荷，获得了 46 种弹性。为土地利用分类（例如，森林、农业、城市），通常代表水源水质。结果表明，大多数参数和土地利用分类的估计弹性范围相对较大。然而，对于在模型中纳入与经济理论一致的控制变量的研究，平均弹性较小，范围通常较窄。我们讨论了这些发现对 DWTP 参与源水保护的激励的影响，并强调了文献中的空白。