长湖水环境需水量与引清济湖研究

Research on Environmental Water Requirement and Clean Water Diversion from Rivers to Changhu Lake

以长湖为研究对象,在对长湖水环境现状和流域污染负荷进行充分调查分析的基础上,结合流域水系特征,采用水质模型分析计算了长湖水环境需水量;针对水环境需水量亏缺的状况,提出了引清济湖方案。最后,预测分析了引清调水的环境效果与制约性因素,为开展长湖流域水环境综合治理与长湖调水工程的实施提供重要的科学依据。结果表明:为达到长湖Ⅲ类水质控制目标,2010年现状污染负荷与2020年削减污染物负荷后两种情况下长湖的最小水环境需水量分别为40.63、3.26亿m3,水环境缺水量分别为33.12、1.26亿m3。为保证2020年长湖达到Ⅲ类水质目标,从外流域实施引水流量应达到21.30m3/s。控制污染源、减少入湖污染负荷是长湖水污染综合治理的基础和根本,而实施引清补水是水污染防治和水生态修复潜能均得以充分发挥作用下的有益补充,是改善水环境质量的辅助及应急措施。

Taking Changhu Lake as the object of study, based on a full investigation and analysis of present water environment, pol- lution load as well as characteristics of water networks in Changhu Lake Basin, this paper calculates and analyzes environmental wa- ter requirement in Changhu Lake by means of water quality model. In view of the shortage of water requirement for environment in Changhu Lake, it comes up with a scheme for clean water diversion from rivers to Changhu Lake. Finally, it predicts environmental effect of clean water diversion and analyzes some restrictive factors. The paper provides an important scientific basis and technical support for the comprehensive treatment, and implementation of water diversion projects in Changhu Lake Basin. The results show that： if water quality of Changhu Lake is up to the standard of Grade Ⅲ, the minimal environmental water demand is 40. 63 × 10^8 m3 in 2010 with current pollutants load, and 3.26× 10^8 m3 in 2020 with reduction in pollutants load, which leads to the water shortage in quantity of environment in Changhu lake is 33.12 × 10^8 m3 , 1.26× 108 m^3 respectively in 2010 and in 2020. In order to ensure that water quality of Changhu Lake is up to the standard of Grade Ⅲ, the flow of water diversion from outside watershed to Changhu Lake should reach 21.30 m3/s. On the one hand, t control of sources of pollution and reduction in pollutants load which inflow into the lake is the basis of comprehensive treatment for water pollution in Changhu Lake, on the other hand, the implementation of clean water supplement is not only a beneficial supplement to the prevention and control of water pollution as well as the restoration of wa- ter ecosystem which are at their best, but also the subsidiary and an emergent measure to improve quality of water environment.