强潮河口环境和生态需水及其计算方法

Calculation methods of environmental and ecological water demand for macro-tidal estuary

针对钱塘江河口以海域来沙为主的强潮河口特点,提出其环境和生态需水,包括维持河口冲淤平衡需水、防止河口咸水入侵需水、维持河口水功能区水质达标需水及最小生态需水。研究了各部分需水的计算方法,在一定计算条件下给出了定量的计算结果。根据分时段考虑原则、兼容性原则和区域性原则,对环境和生态需水的综合计算方法进行了探讨。研究表明,钱塘江河口环境和生态需水年总量主要由维持河口冲淤平衡需水决定,占多年平均来水量的80%,而年内不同时期需水的主要控制因素不同,并随计算条件发生转化。

The Qiantang estuary is a macro-tidal estuary with heavy landward sedimentation. According to the characteristics and main functions of this estuary, the calculation methods for environmental and ecological water demand including the water demand for balance of sediment transport, water demand for balance of salinity, water demand for diluting the pollutant loads to meet the requirement of water quality and the minimum ecological water demand for habitants in the estuary are suggested, are and the quantitative calculation results for specific targets are derived. The method for integrating these water demands based on the principle of time sharing, compatibility and pertaining to a region is established. The study result shows that the major amount of water demand for Qiantang estuary is the water demand for sediment transport, which is about 80% of the yearly average runoff of the river. However, the total water demand in different seasons is dependent on various water demand components and varies with the calculation conditions.