基于鱼类栖息地盐度需求的汛期河口生态需水研究

Estuarine Ecological Water Requirement for Flood Season Based on the Salinity Demand of Fishes Habitat

海河流域枯水期中下游河道基本干涸,汛期来水基本上是河口全年生态维持水量的惟一来源。根据汛期河口水生态系统的特点,选择鱼类为河口水生态系统的关键种群,以盐度作为关键生态因子,构建基于生态学和水动力学的汛期河口生态需水计算模型。以海河流域漳卫新河河口为例,采用改进熵值法进行河口及邻近海域鱼类优先保护次序评价,确定蓝点马鲛(Scomberomorus niphonius)和半滑舌鳎(Cynoglossus semilaevis)作为优先保护对象。在此基础上,运用1维水流和盐度数学模型模拟河口盐度与流量相关关系,以优先保护鱼类产卵和育幼的适宜盐度为控制条件,计算得到汛期漳卫新河河口最小和适宜生态流量分别为10.1、57.5 m3/s,揭示水动力特性变化导致鱼类栖息地盐度及其生态需水的变化规律。

Based on ecology and hydrodynamics,a model for evaluating the estuarine ecological water requirement for flood season was established.Fishes was chosen as estuarine aquatic ecosystems key populations,and salinity was determined as the key ecological factor based on characteristics of estuarine aquatic ecosystems.The model was tested on the data from the Zhangweixin River Estuary（ZRE） in Haihe basin.The improved entropy method was used to evaluate the priority conservation order of fishes,and Scomberomorus niphonius and Cynoglossus semilaevis was identified as the priority conservation target in the ZRE and its adjacent sea area.On this basis,the relationship between estuarine salinity and discharge was simulated by using one-dimensional flow and salinity mathematical model.Under the condition of suitable salinity of target species spawning and nursery,minimum and medium ecological flow for flood season was 10.1 and 57.5 m3/s,respectively in the ZRE.The result revealed the change law of fish habitat salinity and estuarine ecological water requirement caused by hydrodynamic characteristic changes.