湖南四水流域适宜森林覆盖率指标研究

以湖南省湘江、资江、沅江和澧水四大流域为研究对象,探索在大尺度上森林覆盖率对水文效应的影响.通过编制水文特征值得分表和精度检验,确定了径流深(y1)、相对河况系数(y2)、河流含沙量(y3)、侵蚀模数(y4)4个水文因子和森林覆盖率(X1)、水利工程数量(X2)、流域形状系数(X3)、平均坡度(X4)、流域面积(X5)、年降雨量(X6)6个流域因子,并建立了它们之间的关系模型,并求出流域在其它因子一定时的该水文因子所要求的适宜森林覆盖率,综合考虑各水文因子在水文生态环境中的相对重要性并进行加权平均,确定流域内适宜森林覆盖率指标分别为:湘江49%,资江47%,沅江51%,澧水50%.

Index Research on the Suitable Forest Coverage of the Four Main Rivers in Hunan Province

This paper explores on a large scale the effects of the forest coverage on the hydrology of the four main rivers in Hunan Province: Xiangjiang, Zijiang. Yuanjiang and Lijiang. Four hydrological factors such as runoff, relative river coefficient, sand content and erosion coefficient and six watershed factors such as forest coverage, water engineering number, watershed shape, average slope, watershed area. annual rainfall are all determined by the hydrological characteristic score table and precise checking. Four models have also been built. The index of the forest coverage suitable for the four main rivers comes from the hi-derivative of the above hydrological factors. After average consideration of each hydrological factor, the index of the forest coverage suitable for Xiangjiang, Zijiang, Yuanjiang and Lijiang is respectively 49%, 47%, 51% and 50%.