引水改善平原感潮河网水质效果评估

以张家港市三大水循环体系为例,构建一维河网水动力水质数学模型,揭示了不同长江潮位与内河引水量的响应关系,不同引水量与河网水质改善效果、引水服务面积的响应关系。结果表明:随着长江高潮位的升高,内河引水量呈现线性增长趋势;当中部水系引水量达到1.4×10~7m~3时,氨氮浓度改善率达到50%以上,浓度变化指数达到0.6以上,且整体提升了1个水质类别;引水服务面积随着引水量的增大呈现线性增长趋势,而单位引水量服务面积呈现对数函数下降趋势,其中东北部水系单位引水量服务面积最大,为0.352～0.891 km~2/万m~3。

Effect evaluation of water diversion to water quality improve in plain tidal river network

Taking the three water circulation systems of Zhangjiagang City as an example, a one-dimensional river network mathematical model of hydrodynamic force and water quality was constructed, which revealed the response relationship between different tidal levels of the Yangtze River and the amount of water diverted from the inland river, and the response relationship between different amounts of water diverted and the effect of water quality improvement and the service area of water diversion. The results show that with the rising of the high tide level of the Yangtze River, the water diversion volume of the inland river presents a linear growth trend. When the water diversion volume of the middle water system reaches 1. 4×10⁷ m³, the improvement rate of ammonia nitrogen concentration is more than 50%, the concentration change index is more than 0. 6, and the overall water quality category is improved by one degree. The service area of water diversion shows a linear growth trend with the increase of water diversion volume, while the service area of unit water diversion volume shows a logarithmic function decline trend. The service area of unit water diversion volume of northeast water system is the largest, which is 3. 52×10^-5~8. 91×10^-5 km²/m³.