巴丹吉林沙漠湖泊水分补给机制的模拟——以苏木吉林湖区为例

Research on the recharge of the lakes in the Badain Jaran Desert: Simulation study in the Sumu Jaran lakes area

巴丹吉林沙漠气候干旱,蒸发强烈,与之形成鲜明对比的是沙漠腹地湖泊群的长久不衰,目前对于湖泊水分的补给来源仍存在争议.本文以水量均衡为基础,在苏木吉林湖区开展了降水、蒸发及湖水位和地下水位的动态监测,结合已有的水文地质资料建立地下水流动三维模型,重现湖区地下水位的季节动态变化,并基于模型进行水均衡分析.结果表明:苏木吉林湖区降水入渗补给量不足以平衡湖泊蒸发量,湖泊需要深层承压水的越流补给;湖水位和地下水位均呈现正弦曲线形态,11月最低,4月达到峰值,水位变幅分别为22和18 cm;湖区地下水多年平均总补给量为11620 m3/d,其中降水和承压水越流分别约占13%和87%,降水补给量夏季高、冬季低,承压水越流补给量季节变化不明显;承压水越流补给量可能主要来源于沙漠周边山区降水,未发现明显的水量亏空需要断裂导水来弥补.研究结果为巴丹吉林沙漠地下水资源分析及合理利用提供科学依据.

The Badain Jaran Desert was located at the northwest inland of China with drought and intensive evaporation. In stark contrast, there were dozens of permanent lakes inside the desert hinterland. Water recharge of the lakes in the Badain Jaran Desert has always been controversial. Based on water balance algorithm, this paper investigated the water recharging mechanism of the lakes. Dynamic observations of precipitation, evaporation, lake level and groundwater level were conducted in the Sumu Jaran lakes area. Based on the data analysis, a 3D model of groundwater was set up to reconstruct the seasonal dynamic characteristics of the groundwater level in the lakes area, and the water balance analysis was carried out. The results indicated that the precipitation wasn＇t sufficient to meet the water loss via evaporation, and leakage of deep confined water was important to maintain the lakes. Both the groundwater level and the lake level showed as a sine curve, and the changing range was 18 and 22 cm, respectively. The maximum and minimum value of groundwater level and lake level appeared in April and November, respectively. The average re- charge rate of the Sumu Jaran lakes for many years was approximately 11620 m3/d, to which the rainfall and leakage of the deep confined water contributed 13% and 87% ,respectively. The former was high in summer and low in winter, while the seasonal varia- tion of the latter was not obvious. The deep confined water, ultimately, was probably formed with rainfall in the mountain areas a- round the southeast Badain Jaran Desert. No obvious water deficit needs to be covered by the groundwater that is transported to frac- tured zone from the remote area. The results can provide scientific gist for the rational use of groundwater in the Badain Jaran Desert.