闸坝对重污染河流水质水量作用规律的分析与讨论

Analysis and Discussion about the Mechanisms of the Impacts of Dams on Water Quality and Quantity of Heavily Polluted Rivers

在人口密度较大、生产生活相对集中、水质污染较严重的流域(如淮河),如果闸坝(或水库)调度不当,常常会导致突发性水污染事故发生。目前,国内在典型闸坝的水质水量作用规律方面的研究还很不足。本文以作者在淮河流域沙颍河槐店闸的前期工作为基础,发现河道实际水质变化情况与先前认识的闸坝作用规律并不完全一致。综合分析其原因,认为以前很少考虑底泥因素。因此,本文预测了考虑底泥之后闸坝对重污染河流的水质水量作用规律,把COD、氨氮浓度变化沿河流位置分别划分为Ⅶ段、Ⅳ段;并提出了在实验结果基础上构建水质模型,进行闸坝扰动河流底泥的模拟研究,重新全面分析闸坝的作用规律;并对闸坝作用规律研究的4个关键问题进行讨论。这对于重污染河流闸坝水质水量联合调度研究将具有重要的指导作用。

The watershed （such as the Huaihe River watershed） characterized by relatively high population density, production centers and serious water pollutions can often suffer abrupt pollution accidents if dams are not operated appropriately. However, studies on the mechanisms of the impacts of typical dams on water quality and quantity are currently insufficient to deal with associated problems. The earlier work performed by the authors in the Huaidian Dam of Shaying River （in the Huaihe River watershed） showed large differences in change mechanisms of water quality which are universally accepted. The results showed that we need to pay more attention to the sediment. Then the mechanisms of the impacts of dams on water quality and quantity in consideration of sediment were discussed in the paper. The change mechanisms of COD and NH4-N along the river where the Huaidian Dam is located, could be divided into seven and four sections to reasonably depict the characteristics of concentration changes in COD and NH4-N along the river, respectively. The framework of the water quality model based on the experiment results was established to simulate the impacts of dams on sediment. Also, four critical issues associated with the studies of functions of dams were discussed in the paper. The first issue is how to clarify river sediment characteristics in an integrated experiment, the second one is how to simulate hydraulic processes of water discharge of dams, the third one is how to consider the influence of sediment in water quality models, and the last one is how to develop scenario simulations and to examine the impacts of dams on water quality and quantity in a heavily polluted river. The potential solutions to these issues would be very useful to understand, simulate and control the functions of dams in heavily polluted rivers.