Dietz Michael E, Clausen John C
Department of Environment and Society, Utah State University, Logan, UT 84322-5215, USA.
J Environ Manage. 2008 Jun;87(4):560-6. doi: 10.1016/j.jenvman.2007.03.026. Epub 2007 May 4.
Development continues at a rapid pace throughout the country. Runoff from the impervious surfaces in these watersheds continues to be a major cause of degradation to freshwater bodies and estuaries. Low impact development techniques have been recommended to reduce these impacts. In this study, stormwater runoff and pollutant concentrations were measured as development progressed in both a traditional development, and a development that used low impact development techniques. Increases in total impervious area in each watershed were also measured. Regression relationships were developed between total impervious area and stormwater runoff/pollutant export. Significant, logarithmic increases in stormwater runoff and nitrogen and phosphorus export were found as development occurred in the traditional subdivision. The increases in stormwater runoff and pollutant export were more than two orders of magnitude. TN and TP export after development was 10 and 1 kg ha(-1) yr(-1), respectively, which was consistent with export from other urban/developed areas. In contrast, stormwater runoff and pollutant export from the low impact subdivision remained unchanged from pre-development levels. TN and TP export from the low impact subdivision were consistent with export values from forested watersheds. The results of this study indicate that the use of low impact development techniques on a watershed scale can greatly reduce the impacts of development on local waterways.
全国各地的开发仍在快速推进。这些流域不透水表面产生的径流仍是淡水水体和河口退化的主要原因。已建议采用低影响开发技术来减少这些影响。在本研究中，随着传统开发区域和采用低影响开发技术区域的开发进程推进，对雨水径流和污染物浓度进行了测量。还测量了每个流域不透水总面积的增加情况。建立了不透水总面积与雨水径流/污染物输出之间的回归关系。在传统分区开发过程中，发现雨水径流以及氮和磷的输出呈显著对数增长。雨水径流和污染物输出的增加超过两个数量级。开发后的总氮（TN）和总磷（TP）输出分别为10和1千克·公顷⁻¹·年⁻¹，这与其他城市/已开发地区的输出情况一致。相比之下，低影响分区的雨水径流和污染物输出与开发前水平相比保持不变。低影响分区的总氮和总磷输出与森林流域的输出值一致。本研究结果表明，在流域尺度上采用低影响开发技术可大大减少开发对当地水道的影响。
