Study on the ecological water level and the ecological groundwater demand in Funing County, Jiangsu Province

The shallow groundwater and surface water in northern Jiangsu plain are interacted and inter-conditioned. Due to the importance of the ecological properties and environmental functions of groundwater, it is essential to study its ecological water level and surplus-deficit characteristics of ecological water demand for ecological protection and restoration. Taking Funing County as an example, based on the analysis of shallow groundwater level dynamics, the index system of ecological water level was determined by the method of statistical analysis and the ecological water level of groundwater was studied, as well as the surplus-deficit characteristics of shallow groundwater ecological water were evaluated on Arcgis platform. The results show that the upper limit of burial depth of ecological water level in most areas of Funing County ranges from 1.5 m to 3 m, and the lower limit ranges from 2.63 m to 3.18 m. In January 2021, about 25.3％ of the regional groundwater level was in the unsuitable extraction area, and the ecological water demand was 5 899 600 m³. In May 2021, the ecological water demand was 7 471 900 m³. In the groundwater unsuitable extraction area, the groundwater extraction and the prohibition of shallow groundwater use should be adjusted accordingly in combination with the situation of water supply within the county area, so that the ecological and environmental functions of groundwater can be efficiently controlled.