Abstract: Taking Shaba Reservoir of Liangping in Chongqing as research object and use the ArcGIS hydrologic analysis mod- el,the sub—watershed after the procedure iS divided and the data of the river network basin are collected and an alyzed．The analysis results indicate tIlat when the drainage area threshold amounts to 3000,the extracting river net is most close to the actual distribution of water system．On the basis of this relationship．13 sub-basins are divided．Moreover,according to a- nalysis 0n eonditions of land use．it is suggested that No．1～5 sub—watersheds around the reservoir are disturbed bv human ’ s activities，especially No．1 sub-watershed，which needs countermeasures to recover．The characteristics derived from the extraction of the lake type water source provide convenience for the management of watershed grading an d recovering，and provide a basis for environment protection of the drinking water source watershed at the same time．

Key words: drinking water sources, lake reservoirs, watershed characteristics, Shaba Reservoir, hydrologic analysis

摘要： 以重庆市梁平县沙坝水库饮用水源为研究对象，利用ArcGIS水文分析模块，对水源地流域的河网进行提取和 子流域划分。结果表明：选用集水面积阈值为3 000时提取的河网与实际水系分布最相近，在此基础上共划分得到 13个子流域。通过对13个子流域土地利用情况的分析，发现人类活动影响主要集中在水库周边的1～5号子流域， 尤其是1号子流域受人类影响最严重，需要采取相应措施对其进行治理。湖库型饮用水源地流域特征提取结果为 流域分级管理和治理提供便利，为饮用水源地流域环境保护提供基础。

关键词: 饮用水源地, 湖库, 流域特征, 沙坝水库, 水文分析