河川枯水径流与极值形成机理研究

主要论述了河川枯水径流与极值的基本特征——枯水流量、枯水发生时间等,重点分析研究了枯水径流与极值形成的机理,即影响枯水径流极值形成机理的地带性因素——气候、植被等,以及枯水径流产生机理的非地带性因素——地质(包括水文地质)、地形地貌和人为因素。通过综合分析认为:不同地带的降水量对枯水径流产生重要的影响;土壤、植被是影响河川枯水径流不可低估的因素;地形对枯水极值有较大的影响;不同地质岩性,因透水性能等的差异,对枯水量及其变化都有不同程度的作用。

Forming Mechanism of River Low Flow and Its Extremum

This paper mainly expounds the hydrographical features of the river low water runoff and its extremum, including discharge variation, occurring time, water quality and water temperature of river low water runoff In the paper, discussion is emphsized on the mechanism of river low water runoff and its influencing factors such as: ① zonal elements, including climate, vegetation, etc.; ② non zonal elements, including hydrogeological condition, geomorphological element, etc.; ③ human made factors The above mentioned mechanism factors interact each other and synthetically affect the river low water runoff and its basic geo distribution The following conclusions could be drawn after a synthetic analysis procedure: (1) River low water runoff is heavily affected by the rainfall of its watershed. The statistic result from the minimum month's flow, shows that river low water runoff has almost the same geo zone as the year's rainfall distribution. In China, river low water flow decreases and presents zonal distribution from rainy area of south east foreland to drought area of north west backland. (2) Soil and vegetation affecting the rainfall's infiltration and speed, are the most important elements to river low water flow. For example, the rate between minimum month's flow and whole year's flow(%) would also increase while the vegetation's covering area in watershed increases. (3) Topography is another important element affecting low water's extremum. The minimum month's flow in highland area would be richer than that in plain area. It also changes proportionally with the size of water assemblage area. This geo referenced law is demonstrated in humid area and semi humid area, or drought area and semi drought area. (4) The rocks, with differential permeability function, would also play a role in low water flow. The minimum month's flow would increase with the rock with high lacuna, and decrease with the low. The research on mechanism or regularity of river low water runoff's formulation, motion and storage, and the geo analysis on relationship between low water's generation procedure and underlayer's hydrological storage system, are most important to estimate or predict low water hydrological parameters. It plays a positive role in rationally developing water resources.