基于麦穗鱼生境模拟的渭河宝鸡段生态基流估算

Estimation of ecological base flow in Baoji section of Wei River by habitat simulation of Pseudorasbora parva

生境模拟法是水力学方法的进一步发展,该方法考虑了生物因素,选取水文因子,应用水动力模型模拟计算生态基流.基于河道内流量增加法(IFIM)原理,本文使用HEC-RAS水动力模型,以渭河宝鸡段林家村水文站至魏家堡水文站之间70km河段为研究对象进行水力模拟;同时选取麦穗鱼为指示物种,考虑生境中流速和水深2个水文因子,绘制生境适宜性曲线,结合水力模拟结果计算得出麦穗鱼的生境可利用面积(AHU),进一步得到流量与生境可利用面积(Q-AHU)关系曲线,曲线第一个转折点对应的流量为生态基流,最高点为最适宜流量.计算结果显示:为保证麦穗鱼生存,渭河宝鸡段所需的生态基流量为10m^3·s^-1;为使麦穗鱼更好地生活繁殖,所需的最适生态流量为20m^3·s^-1;分别占多年(1961-1986年)平均流量的13.4%和26.8%.

Habitat simulation is a further development from hydraulic method.This method takes into account of biological and hydrological factors,and uses a hydrodynamic model to simulate and estimate ecological base flow.The hydrodynamic model of HEC-RAS is used to simulate river reach(at 70km)between Linjiacun and Weijiapu hydrological stations in Baoji section of the Wei River.With two hydrological factors of flow velocity and water depth in habitat considered,habitat suitability curve and habitat available area(HUA) were examined to correlate flow rate and habitat use area(Q AHU)of indicator species Pseudorasbora parva (Temminck et Schlegel).Flow corresponding to the first turning point in the curve is taken as ecological base flow.The highest point is then the most suitable flow.The ecological base flow for Baoji section of the Wei River should be 10m^3·s^-1 to ensure survival of Pseudorasbora parva (Temminck et Schlegel).The optimum ecological flow for improved living and breeding of Pseudorasbora parva (Temminck et Schlegel)is 20m^3·s^-1. The above two flow rates would account for 13.4% and 26.8% of the average annual flow (1961to 1986) respectively.