Climate and Human-Induced Changes in Dunefield Dammed Lakes of Western Mongolia

Abstract

Comparative studies examining the influence of climate change and human factors on the morphometric dynamics of small dunefeild dammed lakes remain limited. This study focuses on Sangiin Dalai and Ereen lakes, located in the southern part of the Great Lakes Depression, Govi-Altai Province, western Mongolia. The study investigates how climate variability and human activities have influenced lake morphometric changes over the past 30 years. The methodology integrated the Normalized Difference Water Index (NDWI), Automated Water Extraction Index (AWEI), Random Forest (RF) machine-learning classification, Mann–Kendall (MK) trend analysis, Innovative Trend Analysis Method (ITAM), Shoreline Development Index (SDI), lake volume estimation, and statistical analyses. The results indicate that lake morphometry has generally decreased during the study period under the influence of regional climate change. Morphometric decline in Sangiin Dalai Lake was primarily associated with climatic variability, whereas changes in Ereen Lake were more strongly controlled by river discharge variations and anthropogenic influences. In particular, satellite image analysis revealed that the rapid decline of Ereen Lake between 2007 and 2011 coincided with the water impoundment period of Gegeen Reservoir. This study highlights the comparative influence of climatic and anthropogenic drivers on the morphometric evolution of dune-dammed lakes in arid regions of western Mongolia and provides new insights into the environmental sensitivity of small inland lake systems under ongoing climate change and human activities.