Groundwater plays a vital role in maintaining water supply security, ecological security, and food security in cold and arid northern China. The surface runoff, groundwater recharge, and river discharge are an essential parts of the hydrologic cycle, which is referred to as the groundwater circulation. Based on the evolution of regional groundwater circulation and artificial regulation, the following 4 aspects are mainly studied at present:

1. Identification and Quantitative Characterization of the Evolution of Regional Groundwater Circulation.

l Constructed an identification system of evolution of regional groundwater circulation based on multiple environmental tracers (water level, water temperature,  isotope,  and hydrochemistry);

l Established a quantitative evaluation method for transformation intensity of river and groundwater based on the 222Rn mass balance model;

l Simulated multistage groundwater circulation processes of 9 large watersheds or regions in north China and quantitatively evaluating the regional groundwater renewability.

2. Serving the Development and Utilization of Groundwater Resources in Arid Areas.

l Delineated1extra-large groundwater source (750,000 m3/d) and 5water sources with water supply potential(total available exploitation amount 650,000 m3/d) in Nalenggele River Basin, Qaidam Basin;

l Provided a scientific basis for the rational development and utilization of water resources and the protection of the ecological environment in the Qaidam Basin.

3. Plugging Mechanism of Artificial Recharge Porous Media and Key Technology of Infiltration Enhancement.

l Revealed the plugging mechanism of porous media in physical, chemical, and biological and the effect of reducing infiltration recharge in aquifer recharge process;

l Established the simulation and prediction model of blockage evolution under different conditions;

l Formed 7 patented technologies for artificial infiltration of groundwater with increasing engineering infiltration rate by more than 3 to 5 times.

4. Demonstration Project of Artificial Recharge of Groundwater.

l Participated in the scheme proof and demonstration of 8 artificial groundwater recharge projects;

l Undertook the national key research and development project on ‘Artificial Recharge and Storage of Groundwater in Xiongan Area’.

Figure 1. Blockage-seepage process experiment and coupling simulation conceptual model

Figure 2. Water source pretreatment test