基于生态保护目标的武江流域生态流量定值研究

Research on Ecological Discharge Based on Ecological Protection Objective in the Wujiang River Basin

基于武江河道内的生物多样性和物种特征,提出适宜水力学指标法计算维持河道生态系统稳定性所需的生态流量。该方法以代表鱼类为生态保护目标,根据湿周、流速与流量的关系,求得鱼类不同生命周期的生态流量。结果表明:(1)越冬期鱼类所需流速下限为0.2m/s,产卵期平均流速为0.5~0.7m/s,肥育期流速范围为0.3~0.6m/s;(2)产卵期河道生态流量为116.3~150.3 m/s,越冬期与肥育期中后阶段生态流量为49.55 m^3/s;肥育期初期(8月)生态流量为71.97 m^3/s;(3)提出的适宜水力学指标法以维持鱼类良好的生境条件为生态保护目标,计算结果符合Tennant法河流生态用水标准,且更能反映河流的丰枯变化,可为流域水资源开发利用提供参考。

Based on the biodiversity and species characteristics in the Wujiang River,this paper proposed an appropriate hydraulic index method to calculate the required ecological flow to maintain its ecosystem stability.It took the representative fish as the ecological protection target,and obtained the ecological discharge of fish in different life periods according to the relationship between wetted perimeter,velocity and discharge.The results indicate that(1)the lower limit of flow velocity required for fish in the winter period is 0.2m/s,the average flow velocity in the spawning period is 0.5~0.7m/s,and the flow velocity range in the fattening period is 0.3~0.6m/s;(2)the ecological flow is 116.3~150.3 m^3/s during the spawning period,49.55m^3/s in the winter and middle and late stage of fattening periods,and 71.97m3/s in the early stage of fattening period;(3)the method takes the maintenance of a better habitat condition as the goal of ecological protection,and the calculated results are in line with the Tennant method standard.In addition,the results could better reflect the changes of river abundance and drought.