河口生态环境需水量计算方法研究

Study on the methods for quantifying the environmental flow in estuaries

提出了河口生态环境需水量的计算方法.计算中考虑了水循环消耗、生物循环消耗、生物栖息地等不同类型需水及其随时间的变化,根据“加和性”和“最大值”原则计算了河口生态环境需水年度总量,以保持河口径流自然状态为目标确定了生态环境需水量年内随时间的变化率.根据“生态环境需水量阈值性”的要求,将计算结果划分为最低、适宜和高3个等级.对海河流域主要河口的计算结果表明,海河口、滦河口和漳卫新河口最低等级生态环境需水量分别为5 97×10 8m3、6 81×10 8m3和4 96×10 8m3.河口径流量的减少将首先影响泥沙的输运。

Considering the requirement of the water cycle, the biological cycle and the habitat in estuaries, the methods for quantifying the environmental flow with different functions and the temporal variation respectively are presented. Annual water demands are determined based on the adding and the maximum principle. Month variation of environmental flow is settled to be close to the variation of natural river discharge. Different levels are established in case of the limited requirement for ecological water demands. Calculating methods for quantifying the environmental flow in estuaries are applied in Haihe River Basin. The results indicated that the minimum ecological water demands for Haihe estuary, Luanhe estuary and Zhangweixin estuary were 5.97×10~8 m^3, 6.81×10~8 m^3 and 4.96×10~8 m^3 respectively. Sediment transport will be impacted directly by the reduction of the river discharge, and the balance of salinity will be changed in the estuarine ecosystem.