基于多种水文学方法的赣江下游生态流量估算

气候变化和人类活动改变了天然径流的时空分配过程,水文情势的改变成为水生态系统退化的主要原因之一。开展生态流量研究,可为赣江流域水资源的优化配置、可持续开发利用和水生态系统的恢复提供科学依据。运用RVA(range of variability approach)、90%保证率下月最小日平均流量法、最枯月平均流量多年平均值法、NGPRP法、Texas法、多年日流量排频法(90%)6种水文学方法对赣江流域60多年的逐日流量资料进行研究,分析了赣江流域的生态流量过程,利用Tennant法对比分析,最终选择结合汛期RVA和非汛期多年日流量排频法(90%)下的适宜生态流量为赣江下游各月的适宜生态流量值。其中4—6月为赣江的主汛期,所需生态流量值最大,分别为1 520、1 988、1 924 m~3/s。与外洲站实测流量对比发现,赣江下游枯水期河道生态流量难以得到保障,不达标比例高于13%,尤其以1月和11月最为严重。

Study on ecological flow of Gan River based on hydrology methods

Climate change and human activities have changed the temporal and spatial distribution of natural runoff, and the change of hydrological conditions has become one of the main reasons for the degradation of aquatic ecosystems. The research on ecological discharge can provide scientific basis for the optimal allocation of water resources, sustainable development and utilization and restoration of aquatic ecosystem in Ganjiang River Basin. Using RVA, Q90 (90% guaranteed minimum daily average flow method next month), NGPRP and other hydrological methods, the daily flow data of Ganjiang River basin for more than 60 years were studied, and the ecological flow process of Ganjiang River basin was analyzed. Tennant method was used for comparative analysis. Finally, the suitable ecological flow under the combination of RVA in flood season and multi-year daily flow drainage frequency method in non-flood season (90%) was selected as the lower reaches of Ganjiang River. Appropriate monthly ecological flow value. Among them, April to June is the main flood season of Ganjiang River, and the ecological flow value required is the largest, 1520 m3/s, 1988 m3/s and 1924 m3/s, respectively. Compared with the measured flow of Waizhou Station, it is found that the ecological flow of rivers in the lower reaches of the Ganjiang River is difficult to be guaranteed. The proportion of non-compliance is higher than 13%, especially in January and November.