西北内陆盆地浅层地下水温度场及动态类型:以酒泉东盆地为例

Temperature field and dynamic types of shallow groundwater in the northwest inland basin: A case study of the Jiuquan East Basin

温度是地下水的固有属性,地下水温度场和动态特征是地下水流系统的外在表现。为揭示地下水开采等人类活动影响下西北内陆盆地浅层地下水温度场特征与地下水流系统的关系,基于多点位、长序列、高精度的地下水温度监测数据,在酒泉东盆地开展了地下水温度场及动态特征研究。结果表明:酒泉东盆地浅层地下水温度9.33~20.77℃不等,平均水温为13.54℃,自地下水补给区至排泄区,沿地下水径流方向,浅层地下水温度逐渐升高;循环深度相近的不同地下水流系统对比表明,浅层地下水温度与地下水动力条件呈负相关,地表水入渗补给大、水动力条件强的水流系统地下水平均温度低,入渗补给小、水动力条件弱的地下水平均温度高;浅层地下水温度动态受自然地下水循环和地下水开采等人类活动共同影响,从山前地下水补给区到中游绿洲区再到下游排泄区,浅部地下水温度动态可划分为4种基本类型,依次分别为河流补给型、水温稳定型、开采相关型、正弦波动型。

Temperature is an inherent property of groundwater.Groundwater temperature field and dynamic characteristics are objective manifestations of groundwater flow system.Based on multi-point, long series and high precision groundwater temperature monitoring data, the characteristics of shallow groundwater temperature distribution and dynamic type of water temperature in Jiuquan East Basin are studied, in order to reveal the relationship between the characteristics of shallow groundwater temperature field and groundwater flow system under the influence of human activities such as groundwater exploitation in northwest inland basin.The results show that the shallow groundwater temperature ranges from 9.33℃ to 20.77℃,and the average water temperature is 13.54℃.From the recharge area to the discharge area, the shallow groundwater temperature increases gradually along the direction of groundwater runoff, and the average groundwater temperature in January is higher than that in July.The comparison of different groundwater flow systems with similar circulation depth shows that the shallow groundwater temperature is negatively correlated with groundwater dynamic conditions.The average groundwater temperature of the water flow system with large surface water recharge and strong hydrodynamic conditions is lower, and that of the water flow system with small recharge and weak hydrodynamic conditions is higher.The temperature dynamics of shallow groundwater are affected by human activities such as natural groundwater circulation and groundwater exploitation.From groundwater recharge area to oasis area in the middle reaches and drainage area in the lower reaches, the temperature dynamic of shallow groundwater can be divided into four basic types, which are river recharge type, water temperature stability type, groundwater exploitation related type and sinusoidal fluctuation type respectively.