滴水湖是一个面积约4.5 km2的人工湖,位于上海海港新城的市中心.降雨期间,城市地表径流经过规划的网状水系汇入到滴水湖,经过与湖沟通的海闸排到东海.根据远景规划,滴水湖的水质需要满足城市娱乐和景观用水要求.因此,维持滴水湖良好的水质显得尤为重要.耦合一个简单的城市降雨-径流模型,CE-QUAL-W2 水质模型被用来模拟远景年滴水湖的水质.模拟了3个不同年降雨概率的典型年,即2003(90%)、2004(50%)和2002(10%)年.模拟的污染指标主要有溶解氧(DO)、藻类、生化需氧量(BOD5)、总磷(TP)、氨氮(NH3-N)和总氮(TN).结果显示,在3个典型年里滴水湖的综合水质能够维持在地表水Ⅲ～Ⅳ类.比较而言,在90%降雨保证率年,滴水湖的水质最好,因为地表径流最小以至携带的地面污染负荷最少.从各污染指标的日平均值来看,在各个典型年里DO优于Ⅲ类, 因此远景年的水质对湖中的鱼类等生物几乎没有负面影响.%The Dishui Lake, a 4.5 km2 round central man-made lake, lies in the city centre of new harbour town, Shanghai. It will receive all drainage from the urban catchment before discharging to the sea via sea gates. The water quality in the lake become specific concerns in the present study. In this paper, coupled with a simple urban rainfall-runoff model, CE-QUAL-W2 model was employed to simulate its water quality. Simulations were carried out in three representative years with annual rainfall probabilities of 90%(2003), 50%(2004), and 10%(2002)). The simulated pollution loadings mainly included DO, algae, BOD5, TP, NH3-N and TN. Results show that comprehensive water quality in the lake can be maintained at national surface water quality class Ⅲ～Ⅳ in each representative year. Comparatively speaking, the best water quality occurs with the probability of 90%(2003) because the least pollution loads have been washed off along with storm water runoff in the year. From the perspective of daily average value, DO levels are all better than Ⅲ class, which nearly exerts no adverse impacts on fish survivals.
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