The role of climate and human influences in the dry-up of the Jinci Springs, China

One of the largest karst springs in North China, the Jinci Springs, dried up and has remained dry since 1994. We develop a correlation analysis with time-lag and a regression analysis with time-lag to study the relation between spring flow and precipitation. This allows us to obtain a better understanding of karst hydrological processes by differentiating the contribution of variation in precipitation from anthropogenic impacts on the dry-up of Jinci Springs. We divided the karstic hydrological processes into two phases: pre-1961 and post-1961. In the first phase (i.e., 1954-1960) the groundwater recharge was affected by precipitation alone, and in the second phase (i.e., 1961-1994) the groundwater recharge was influenced by both precipitation and human activities. Using precipitation and groundwater recharge data in the first phase, we set up a groundwater recharge model with time-lags. By running the time-lags model, we acquired the groundwater recharge likely to occur under the sole effect of precipitation in the second phase. Using a water-balance calculation, we conclude that the groundwater recharge exhibited statistical stationarity, and the Jinci Springs dry-up was the result of anthropogenic activities. At least three specific types of anthropogenic activities contributed to the drying-up of Jinci Springs: (1) groundwater pumping accounts for 51%, (2) the dewatering from coal mining accounts for 33%, (3) and dam-building 14%. The drying-up of Jinci Springs meant that the groundwater drained from the aquifer's fractures, and subsequently changed the structure of the karst aquifer. Although groundwater exploitation has been reduced, the flow at Jinci Springs has not reoccurred.