嘉兴市是水资源短缺且源水水质较差的地区 ,每到多雨季节因河网水系的调蓄量不足 (仅为 2 .79× 10 8ｍ3 ａ)而造成大量的雨水外排 (达 16× 10 8ｍ3 ａ)。为避免淡水资源流失 ,采取较合理的方法是在沿河流域(主河道上 )开挖一些大型人工湖泊。若开挖 2 0 0个表面积约为 1ｋ Jiaxing City is a region with a shortage of water resources and poor water quality. Due to the shortage of water storage capacity (only 2.79 × 10 8 m 3 a) in rainy seasons, a large amount of rainwater discharge (up to 16 × 10 8m3 a). In order to avoid the loss of freshwater resources, a more reasonable method is to excavate some large-scale artificial lakes in the river basins (the main rivers). If excavation 200 surface area of ​​about 1k