水文指数法确定河流生态需水

河流水文情势是河流生态系统的自然动力学特征，而径流情势是水文情势的重要特征。根据生物种群和环境因子之间的关系，从反映河流水文情势的径流情势中筛选水文指数，构建河流生态需水的计算方法。从径流情势中提取流量、频率、历时、发生时间、变化率5个水文指数确定河流生态需水。采用水文指数法实际计算了广东省河流的生态需水，并和Tennant法进行比较分析，结果表明，采用水文指数法计算河流生态需水是可行的。

Estimation of instream flow based on hydrological indexes

Hydrological regimes play a major role in determining the biotic compoisition, structure, function of aquatic, wetland, and riparian ecosystems. Human land and water uses are substantially altering hydrologic regimes. According to the characteristic of the change is the motive power of maintaining river ecosystem river ecosystem, the view that river hydrology integrality is pointed out alter having expatiated on a relation between fiver ecological environmental and fiver hydrology change. It turned out that the hydrology change of the fiver is reflected through the change of the flow. Hydrological indexes based on ecological relevant factors in the flow-quantity, time, frequency, lasting and rate of change are selected. A new method of instream flow is put forward. The relation between the regional ecosystem health and composite index of hydrology has been studied to make certain the degree of hydrology change of river, which will offer the theoretical foundation for sustainable utilization of the water resource. The case in Guangdong Province has proved that the hydrology index method applied to instream flow is feasible.