敦煌月牙泉湖近百年水位变化及其原因分析

敦煌月牙泉形成于第四纪全新世，距今约12 ka。因泉湖地处鸣沙山环抱之中，形似月牙并兼具沙水共生的淡水泉湖特征，成为世界瞩目的自然地理环境的重要地质遗迹。对月牙泉湖近百年水位动态变化进行了综合分析，认为月牙泉湖水位动态变化的综合原因可归结为气候和人为因素。1960年开始农业打井灌溉、党河水库和渠系的修建导致地下水补、排失衡，到2001年月牙泉湖水位下降9. 98 m，年均下降0. 24 m，致使区域性地下水位的下降是造成月牙泉湖水位下降的主要原因，气温的升高加大蒸发量是月牙泉湖水位动态变化的次要原因。通过月牙泉人工补水工程，2018~2019年月牙泉湖水位上升1. 58 m，湖水域面积由9472. 59 m2逐渐扩大到13334. 75 m2，昔日古人心中美丽的月牙泉面貌再次展现在我们的眼前。

The change of water level and its causes in Crescent Lake in Dunhuang area in the last 100 years

The Dunhuang Crescent Spring (Crescent Moon Spring, Yueya Spring, Crescent Lake) was formed in the Holocene of the Quaternary Period, about 12 ka ago. Because the spring lake is surrounded by the Mingsha Mountain, it looks like a crescent moon and has the characteristics of freshwater spring lake with the sand and water symbiosis, which has become an important geological heritage in the world. Based on the comprehensive analysis of the dynamic changes of water level in Crescent Springin in the last 100 years, it is considered that the comprehensive reasons for the dynamic change of water level in Crescent Spring can be attributed to climate and human factors. From 1960, agricultural well irrigation and the construction of the Danghe Reservoir and canal system led to the imbalance of groundwater recharge and discharge. By 2001, the water level of Crescent Spring had decreased by 9.98 m, with an average annual decrease of 0.24 m. The decline of regional groundwater level was the main reason for the decline of water level in Crescent Spring, and the increase of temperature and evaporation is the secondary reason for the dynamic change of water level in Crescent Spring. Through the artificial water supplement project of Crescent Spring, the water level has risen by 1.58 m from 2018 to 2019, and the water area of the lake has gradually expanded from 9472.59 m2 to 13334.75 m2. The beautiful appearance of Crescent Spring in the minds of the ancients has displayed again.