Chemical and isotopic response to intensive groundwater abstraction and its implications on aquifer sustainability in Shijiazhuang, China

Abstract

The stress imposed on groundwater resources due to intensively exploited aquifer has resulted in groundwater depletion in the North China Plain (NCP). Management of groundwater resources needs to understand the changes or dynamic responses due to the exploitation. The response of groundwater systems to intensive exploitation and groundwater availability were assessed by the combined use of conventional hydrochemical data and environmental isotopes in Shijiazhuang, NCP. The generally increased concentration of total dissolved solids (TDS), major cation and anion of groundwater in the past 40 years indicated high vulnerability of aquifer system but a short turn over time by intensive groundwater exploitation, which also was proved by changes of groundwater renewal rate estimated by tritium. The vertical distribution of tritium in aquifers showed that the active groundwater recharge zone has been extended from the depth of 100 to ~150 m since 1985, indicating an enhancement of active groundwater flushing of local groundwater system due to intensive groundwater abstraction. The enrichment trend of δ18O and δ2H value with groundwater abstraction, suggested the impacts of local recharge from irrigation return. The increase concentrations of nitrate with time indicated high aquifer vulnerability. A comprehensive effort should be developed for effective management strategies that ensure long-term, stable, and flexible water supplies to meet water demands in the NCP.