钱塘江河口抗咸流量预报模式及其检验

Prediction model of salinity-resisting discharge in Qiantang Estuary and its validation

钱塘江河口咸水入侵的影响因素有径流、潮汐、江道地形、取水量等,其中径流和潮汐的相互作用是取水口盐度是否超标的决定因素。基于咸水入侵的主要影响因素,分析抗咸流量预报的关键点,建立了取水口盐度超标时间与径流、潮差的定量响应关系,构建了抗咸流量预报模式,给出了模式中各参数的计算方法。将该预报模式应用于钱塘江河口2012—2014年的最小抗咸流量模拟预报,经实践检验,按照预报值调度下泄流量,可满足杭州市抗咸要求。抗咸实践表明,不仅大潮期需保证足够的抗咸流量,中、小潮期泄放流量也不得小于预报流量。

Runoff, tides, riverbed morphology, and water intake influence saltwater intrusion in the Qiantang Estuary. Of these factors, runoff and tides are the decisive factors that determine whether the salinity at the intake exceeds the standard. Based on the main factors in saltwater intrusion, key issues in predicting the salinity-resisting discharge were analyzed, and a quantitative relationship regarding the response of the standard-exceeding time to the runoff and tidal range was established. A model for predicting the salinity-resisting discharge was built, and computational methods for parameters in the model were proposed. The prediction model was applied in the prediction of minimum salinity-resisting discharge in the Qiantang Estuary from 2012 to 2014. The validation results show that reservoir operation based on the predicted discharge can satisfy the salinity-resisting demand of Hangzhou City, and a discharge sufficient to resist saltwater intrusion must be guaranteed not only during spring tides but also during mid-and neap tides.