GIS-aided Analysis of Ecological Water Requirement of Dry Land System in Yanhe Watershed

摘要

In this research,based on continuous 30-year weather condition report data and 10-year soil water content data in Yanhe watershed,a comparatively accurate method for measuring the minimum,moderate and maximum ecological water requirement of dry land ecosystem has been put forward by using experiential models and GIS spatial analysis.Additionally,the change characters of ecological water requirement for plantsoil landscapes have been addressed from spatialtemporal dimensions.The results show that:(1) Toward the dry land system in Yanhe watershed,the ecological water requirement of plant-soil landscapes is more in summer than in other seasons;(2) The locations of ecological water holding higher requirement mainly lie in the loess undulating ground with beam-figure in the south of Yanhe watershed;(3) The locations of ecological water keeping lower requirement mainly lie in river valley terrace;(4) The mean annual precipitation can only satisfy the minimum ecological water requirement,but cannot meet the moderate or maximum ecological water requirement.