基于极度干旱的喀斯特高原山地与峡谷水资源优化配置方式对比——以贵州花江峡谷南岸和毕节朝营小流域为例

Water Resources Optimal Allocation Mode for Extremely Arid Mountains and Valleys on Karst Plateau——A case study of the South Bank of Huajiang Canyon and Chaoying Small Watershed of Bijie City,Guizhou Province

以喀斯特峡谷和山地地貌典型缺水山区为例,基于气候极度干旱条件,在弄清区域水资源赋存特征和降雨时序基础上,分析了不同干旱情景下供需平衡情况。结果显示:一般干旱情景下,喀斯特峡谷区靠水窖(池)储水能满足饮水需求,喀斯特山地区地表水资源量和储存水量也达到饮水需求量,但由于利用效率低,缺水现状成为常态。气候极端干旱情况下,峡谷区地表水干枯,极度缺水时间超过2个月;山地环境地表水量大幅度减少,可用水量不足需水量50%,人畜饮水极为困难。根据区域水资源时空分布及人居格局特点,采用"集中引水,分散供水"方式,从花江示范区6km外引入流量稳定的地下水,经多级分流向南岸整个区域自流供水,解决3 850人和435头牲畜饮水安全;通过从朝营流域外5km引入稳定水供给上游使用,从而将上游水源腾出来调入中下游区域,并与当地水资源工程结合起来利用,采用多级收集洼地泉点、堵截-地下河提水方式,集中向洼地周边供水,使流域3 449人和3 446头牲畜饮水得到保障。

This paper took the typical water-deficient mountain areas in Karst mountains and valleys as examples to find out the occurrence characteristics of water resources and rainfall time distribution in the areas based on the climate conditions of extreme drought,and then analyzed the co-ordination of supply and demand under different drought levels.The results showed that under the circumstances of moderate drought,the demand for drinking water in the Karst valley area could be met by using cisterns（pools）to store water,and the available surface water and stored water in the Karst mountain area could also meet the demand for drinking water;however,due to the low utilization rate,water shortage in the areas had became the normal state.Under the circumstances of extreme drought,the surface water in the valley area dried up and the extreme drought lasted for more than 2months;the surface water in the mountain area lost greatly,both people and livestock severely lacked drinking water,and the available water quantity was less than 50% of the water demand.According to the time-space distribution of water resources and the dweller-distributing characteristics in the areas,the project adopted the mode of＂centralized water diversion and decentralized water supply＂,diverted the underground water with constant flow 6km away from Huajiang demonstration area to supply the entire south bank by gravity flow after multi-level branching;in this way,the drinking water safety of 3 850 people and 435 domestic animals was guaranteed.By diverting stable water resource 5km away from Chaoying watershed to supply the upstream,the upstream water was transferred to the middle and lower reaches;the project combined the upstream water with the local water projects and mainly supplied water to the places around depressions by collecting water from depression spring points at multiple levels,cutting off and drawing water from underground rivers;by these measures,the drinking water for 3 449 people and 3 446 domestic animals in the watershed was finally guaranteed.