北三河流域水资源供需平衡对降水变化的敏感性

Sensitivity analysis of water resources supply and demand balance to precipitation changes in Beisanhe River Basin

分析不同区域水资源供需平衡对降水变化的敏感性,并结合考虑云水资源和降水效率的空间分布,有助于常态化人工增雨作业地点的确定,对实现空陆水资源的统筹利用具有重要意义。以北三河流域为研究区域,基于新安江模型和彭曼-蒙特斯公式分析了研究区需水量对降水变化的响应,并探讨了不同计算单元水资源供需平衡对降水变化的敏感性。结果表明:当降水量增加时,流域平水年产水量增加的比例大于枯水年与特枯年,农田灌溉需水量随降水量的增加大致呈线性减小趋势;在不考虑外调水和地下水超采的情况下,自然降水情景的流域资源性缺水量分别为35.46亿m^(3)(降水频率p=50%)、43.17亿m^(3)(p=75%)和46.30亿m^(3)(p=95%),缺水峰值分别出现在5月、7月和8月;各单元缺水量对降水变化的敏感性主要由产水变化主导,空间上呈由北向南逐渐递减的趋势,当平水年降水量增加20%时,北部地区缺水量相对减少率达到150%以上,中部介于30%~50%,南部则小于15%。

Analyzing the sensitivity of water supply and demand balance in different regions to changes in precipitation,based on the spatial distribution of cloud water resources and precipitation efficiency, is helpful to determining the location of normalized artificial precipitation enhancement, and is of great significance to the realization of the coordinated use of air and land water resources. We take the Beisanhe River Basin as the research area, analyze the response of the study area’s incoming water demand to precipitation changes based on the Xin’anjiang Model and Penman-Montes formula, and discuss the sensitivity of the water supply and demand balance of different computing units to precipitation changes. The results show that when precipitation increases, the rate of increase in annual water production in the basin is greater than that in dry years and extreme dry years, and the water demand for farmland irrigation is roughly linear. Without considering external water transfer and groundwater overexploitation, the resource water shortage of the basin under the natural precipitation scenario is 3.546 billion cubic meters(precipitation frequency p=50%), 4.317 billion billion cubic meters(p=75%) and 4.630 billion cubic meters(p=95%), and the peak of water shortage appears in May, July and August, respectively. The sensitivity of each unit’s water shortage to changes in precipitation is mainly dominated by changes in water production, and shows a gradual decrease in space from north to south. When the average annual precipitation increases by 20%, water shortage in the north region will reach 150% or more, the central region will be between 30% and 50%, and the southern region will decrease by less than 15%.