Sustainable exploitable potential of shallow groundwater in the North China Plain

As the most important water resource in the North China Plain (NCP), agricultural, economic and social development has heavily relied on shallow groundwater. Supported by data and results of the project of Investigation and Evaluation of Sustainable Utilization of Groundwater, the paper calculated the exploitable amount of shallow groundwater, and evaluated the exploitable potential and sustainable utilization potential of shallow groundwater in the NCP. The total exploitable amount of shallow groundwater in the NCP was 202.94 × 10⁸ m³ a^-1, with a modulus of 14.58 × 10⁴ m³ a^-1 km^-2. Shallow groundwater was unevenly distributed in the NCP, abundant in the piedmont plain and along the Yellow River, and scarce in the middle and eastern plain regions. The estimated exploitable potential coefficient was 1.15, suggesting equilibrium between exploitation and recharge with high exploitable potential in the whole NCP region. But the exploitable potential distribution was very uneven, with the maximum value in Binzhou of Shandong Province (5.16), followed by Tianjin (4.18), and the minimum value in Shijiazhuang (0.72), followed by Langfang (0.75) in Hebei Province. The evaluation results suggested that the exploitable potential of shallow groundwater was almost exhausted. Specifically, freshwater had been over-exploited in several sections with no sustainable utilization potential. On the contrary, some 35 × 10⁸ m³ a^-1 brackish water and saline water resources in the Hebei Plain alone could be exploited to improve sustainable utilization potential of shallow groundwater in the NCP. This, however, required solving the exploitation and utilization difficulties associated with saline water. This research provided guidance for optional water resources allocation and development of the agricultural, economic and social sectors in the NCP.