中文摘要：

采用小波分析法,对西安市区主要地表供水水源黑河、石头河水库、石砭峪水库年径流序列进行周期性和变化趋势分析.结果表明,各径流序列均具有多时间尺度周期性变化规律并有较显著的下降趋势.即,对应于23,30,8,11 a的周期变化,2020-2030年黑河径流将处于偏枯阶段;从较大时间尺度14 a分析,2023年左右石头河水库径流将处于偏枯阶段;从20 a尺度分析,2022年左右石砭峪河水库径流也可能处于偏枯年份.为了保证该时段西安市区供水,建议提前采取有效措施,积极开发其他供水水源.

英文摘要：

Xi＇ an City is in serious shortage of water resources, and there are some problems in water consumption, such as the irrational exploitation and utilization of water resources, high exploitation and utilization level of groundwater, low utilization efficiency of surface water, and limited volume of exploitable water resources. Xi＇an City is densely populated, but the volume of surface water is 4.7 × 10^7 m^3 only. In this paper, wavelet theory is used for analyzing the periodicity and variation trend of annual runoff volumes of surface water supply in the urban area of Xi＇an City from the Heihe River, Shitou River and Shibianyu River. The results show that there are the multiple variation temporal periods of runoff series of these three water sources, i.e., the 23-year, 30-year, 8-year and ll-year periods, and the runoff volumes of the three rivers are in a significant decrease trend. It is predicted that the steam flow of the Heihe River will be reduced during the period from 2020 to 2030. Analyzing from the 14-year temporal scale, the inflow of the Shitou River Reservoir will be reduced around 2023 ; analyzing from the 20-year temporal scale, the inflow of the Shibianyu River Reservoir will also be reduced around 2022. In order to realize the sustainable .social and economic development in Xi＇an City, it is essential to meet the water demand in the future. So it is suggested to take some effective measures for saving water and exploiting the new water sources.