The Effect of Groundwater Table Lowering on Ecological Environmentin the Headwaters of the Yellow River

Abstract

Owing to climate change and human activities, regional groundwater table and ecological water table are generally decreasing, resulting in a series of environmental geological problems, such as degradation of swampy meadow and vegetation, and desertification. On the base of field survey, the cause of the groundwater table decreasing is analyzed, and the relationship between the ecological environmental effect and groundwater table lowering is discussed. It is found that groundwater table has greatly changed. The groundwater outcrop in mountain areas are moving downwards with decreasing runoff. The groundwater table of civil well in river valleys has fallen 0.52 to 1.18 m. Meanwhile, lake shrinking causes groundwater table lowering around the basin and the outcome in alluvial and diluvium deposits also moves downwards. The groundwater table lowering is caused by permafrost degradation, geological structure action, lake shrinking and human activities. The survey results show that permafrost is in degradation in the headwaters of the Yellow River, discontinuous permafrost degrades into thawed area, the lower boundary of permafrost is rising, and permafrost table is decreasing. The permafrost degradation results in cryogenic waterproof layer moving downward and groundwater table obviously lowering. With groundwater table lowering, a series of ecological environmental problems appear. Swampy meadow and vegetation is in degradation and biological diversity is on the decrease owing to the ecological water table lowering and the depth of seasonal thaw layer increasing. Desertification is enlarging.