Kim Sang M, Brannan Kevin M, Zeckoski Rebecca W, Benham Brian L
a Department of Agricultural Engineering (Institute of Agriculture and Life Science) , Gyeongsang National University , Jinju , Gyeongnam , Republic of Korea.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2014;49(9):1077-89. doi: 10.1080/10934529.2014.895567.
The objective of this study was to develop bacteria total maximum daily loads (TMDLs) for the Hardware River watershed in the Commonwealth of Virginia, USA. The TMDL program is an integrated watershed management approach required by the Clean Water Act. The TMDLs were developed to meet Virginia's water quality standard for bacteria at the time, which stated that the calendar-month geometric mean concentration of Escherichia coli should not exceed 126 cfu/100 mL, and that no single sample should exceed a concentration of 235 cfu/100 mL. The bacteria impairment TMDLs were developed using the Hydrological Simulation Program-FORTRAN (HSPF). The hydrology and water quality components of HSPF were calibrated and validated using data from the Hardware River watershed to ensure that the model adequately simulated runoff and bacteria concentrations. The calibrated and validated HSPF model was used to estimate the contributions from the various bacteria sources in the Hardware River watershed to the in-stream concentration. Bacteria loads were estimated through an extensive source characterization process. Simulation results for existing conditions indicated that the majority of the bacteria came from livestock and wildlife direct deposits and pervious lands. Different source reduction scenarios were evaluated to identify scenarios that meet both the geometric mean and single sample maximum E. coli criteria with zero violations. The resulting scenarios required extreme and impractical reductions from livestock and wildlife sources. Results from studies similar to this across Virginia partially contributed to a reconsideration of the standard's applicability to TMDL development.
本研究的目的是为美国弗吉尼亚州的硬件河流域制定细菌的总最大日负荷（TMDL）。TMDL计划是《清洁水法》要求的一种综合流域管理方法。制定TMDL是为了满足当时弗吉尼亚州关于细菌的水质标准，该标准规定大肠杆菌的日历月几何平均浓度不应超过126 cfu/100 mL，且单个样本的浓度不应超过235 cfu/100 mL。细菌损害TMDL是使用水文模拟程序 - FORTRAN（HSPF）制定的。利用硬件河流域的数据对HSPF的水文和水质组件进行了校准和验证，以确保该模型能充分模拟径流和细菌浓度。经过校准和验证的HSPF模型用于估算硬件河流域中各种细菌源对河流中细菌浓度的贡献。通过广泛的源特征描述过程估算细菌负荷。现有条件的模拟结果表明，大部分细菌来自牲畜和野生动物的直接排泄物以及透水土地。评估了不同的源削减方案，以确定符合几何平均和单个样本最大大肠杆菌标准且无违规情况的方案。结果显示，所得到的方案需要对牲畜和野生动物源进行极端且不切实际的削减。弗吉尼亚州其他类似研究的结果部分促成了对该标准在TMDL制定方面适用性的重新考量。
