干旱区山地典型流域不同景观结构的水文调节能力分析

在GIS支持下,对祁连山中段典型流域不同景观结构的水文效应进行比较分析.结果表明:以低海拔乔木林占优势的大野口河流域可对其年降水量的36.45%进行调节,雨季径流深是旱季径流深的8.43倍;以较高海拔灌丛占优势的海潮坝河流域可对其年降水量的24.96%进行调节,雨季径流深是旱季径流深的11.8倍.大野口河流域对降水的调控能力强于海潮坝河流域.在降水量不变的情况下,流域森林面积每增加1 km²,流域对降水的综合调节能力将提高0.35 t.100 m^-2(即3.5mm).

Hydrological Adjusting Functions of Different Landscape Patterns in Typical Catchments in Qilian Mountains

The relationship between forest and water budgets of mountain catchments is the subject either in ecology or hydrology.The eco-hydrological effects of the forest landscape pattern in the Qilian Mountains of the northwest China are evaluated with the cases of the Dayekou River catchment(DYK) and Haichaoba River catchment(HCB) in this paper.Forest map(1:50 000) of 2001 and topographic maps(1:50 000) are used as inputs to produce the landscape maps.Using ArcGIS,the landscape pattern and eco-hydrological effects of the two catchments are analyzed.The results show that the forest of Picea crassifolia growing on the lower land in DYK are the main landscape elements,doing more important work in the eco-hydrologic system,and the shrubs distributed on the higher land in HCB are the main landscape elements and of importance in eco-hydrological process.Taking the total of water intercepted by crown canopy,holding water capacity by shatter and soil as indexes to determine the integrate hydrology adjusting function,based on the observations and the mean annual rainfall records,using ArcGIS,the integrate hydrology adjusting function of the two catchments is calculated.DYK can regulate 36% of the annual rainfall,and HCB can regulate 24% of the annual rainfall.The integrate hydrology adjusting function of DYK is more strong than that of HCB.When the forest coverage rises from 38% to 51% in DYK,the integrate hydrology adjusting function will rise from 36% to 44%.This study shows that the large area of forest can raise the hydrological effect,and different forest landscape pattern will bring on different eco-hydrological effect.