长江三峡花岗岩区坡面糙率系数研究

Study on the Roughness Coefficient of Slope Face in the Granitic Region of Three- Gorge of the Yangtze River

利用Ｍａｎｎｉｎｇ流量公式基本理论，探讨了花岗岩地区５种不同土地利用类型下的糙率系数ｎ值。研究结果表明：松栎混交林下的ｎ值为０．２２８２，其次为马尾松纯林地、灌草坡面、农耕地和裸地，ｎ值分别为０．１８０６，０．１３２８，０．０７２３和０．０５４６。研究还表明：糙率系数ｎ值较大的地表，其渗透性能亦较好。我国南方花岗岩风化壳上形成的土壤影响糙率系数ｎ值的因子较多，而且其关系较为复杂。

According to the basic theory of Manning equation,the roughness coefficient of 5 kinds ofdifferent land use have been researched. The result shows that the roughness coefficient mixed forestby Pinus massoniana with Quercus acutissima is 0.2282,Pinus massoniana forest land is 0.1806,shrub-grass land is 0.1328,cultivated land is 0.0723,and bare land is 0. 054 6.The result alsoshows that the higher the roughess coefficient of the land is,the bigger its infiltration is. The factorswhich affect the roughness coefficient are more in granitic areas of South China than other areas,therelationships among the factors are also complicated.