基于水文学法的漓江生态流量研究

Ecological flow of Lijiang River based on hydrological method

为了计算漓江的生态流量及确定适宜的生态流量计算方法,基于1954~2017年桂林水文站的逐月平均径流量数据,采用Q90法、年内展布法、Texas法、逐月频率法、NGPRP法和Tessman法6种水文学方法计算漓江的生态流量,从需水程度、水文节律和满足程度3个方面分析了各种计算方法的适用性。结果表明:①在需水程度方面,Q90法在鱼类产卵期和全年范围不满足基本需水量,年内展布法在全年范围不满足基本需水量,Tessman法在一般用水期需水量最大,逐月频率法在鱼类产卵期和全年范围需水量最大;②在水文节律方面,Q90法无法体现丰枯季节性变化;③在满足程度方面,逐月频率法在鱼类产卵期保障率较低,Tessman法在一般用水期、枯水期和全年范围保障率较低;④综合考虑需水程度、水文节律和满足程度3个方面,Texas法是最适用于漓江生态流量计算的水文学方法。最终确定桂林水文站生态流量的逐月取值范围应为11.4~124.0 m^(3)/s。

To calculate the ecological flow of Lijiang River and determine the appropriate calculation method of ecological flow,based on the monthly average runoff data of Guilin hydrology station from 1954 to 2017,six hydrological methods,namely Q90 method,annual distribution method,Texas method,monthly frequency method,NGPRP method and Tessman method were used to calculate the ecological flow of Lijiang River.The applicability of each calculation method was analyzed from three aspects of water demand,hydrological rhythm and satisfaction degree.The results showed that:①In terms of water demand,Q90 method was less than the basic water requirement during spawning period and the whole year,annual distribution method was less than the basic water requirement in the whole year,Tessman method was the largest in the general water consumption period,and monthly frequency method was the largest in the spawning period and the whole year.②In terms of hydrological rhythm,Q90 method could not reflect the seasonalvariation of wetand dry season.③In terms of satisfactiondegree,monthly frequency method had a lower guarantee rate in spawning period,while Tessman method had a lower guarantee rate in general water use period,dry season and annual range.④Considering the degree of water demand,hydrological rhythm and satisfaction degree,Texas method is the most suitable hydrological method for the calculation of ecological flow of Lijiang River.The monthly value range of ecological flow of Guilin hydrology station should be 11.4~124.0 m^(3)/s.