基于SWAT分布式水文模型的河道内生态基流

河道内生态基流是保证河流健康和基本功能不退化的最小流量,但是,现有的一些研究方法很少从流域内水循环的角度考虑.为此,以赣江袁河流域为例,运用SWAT分布式水文模型,根据逐日降雨量等资料进行了情景设计,模拟得到了10％～50％多年平均降雨量下的河流径流、基流等数据,根据生态基流的概念和内涵,重点分析了袁河中上游特定生态功能保护区的生态基流.计算得到芦溪和茅洲2个保护断面的生态基流分别为1.25和17.0 m3/s,占多年平均流量的11.1％和17.4％,并将该结果与其它方法计算得到的生态基流进行了对比分析,结果表明,通过情景设计,使用SWAT模型模拟数据计算得到的河道内生态基流与其它方法计算得到的结果基本一致,说明了使用SWAT模型研究生态基流的可行性.

River Ecological Base Flow Based on Distributed Hydrological Model of SWAT

Ecological base flow (EBF) is a minimum channel flow to maintain a healthy river system and to avoid deteriorating its functions. Recently, research methods in this field are seldom considering this flow from the standpoint of water cycle in a river basin. For this purpose, a case study was conducted in the Yuanhe River which belongs to the Ganjiang River, a branch river of the Yangtze River. In this study, a distributed hydrological model of SWAT was adopted to simulate runoffs and base flows based on daily precipitations and designed scenarios of rainfalls. According to the concept of EBF and the content of base flows, the EBF at the important ecological function zones of the middle to the upper stream of the Yuanhe River was analyzed. Results of the EBF at the Luxi and Maozhou hydrological stations are 1.25 m3/s and 17.0 m3/s, accounting for 11.14% and 17.39% of their averaged annual flows, respectively. In order to verify the reasonableness of these results, they were compared with the results calculated by other methods. Results indicate that they are very close. In addition, EBFs based on a distributed hydrological model of SWAT have the mechanism of water cycle and they should be more reasonable than the values determined by other methods.