Advances in interbasin groundwater circulation

Abstract

Significance Groundwater flow paths may cross the surface divide at the regional scale, resulting in interbasin groundwater circulation that affects hydrological relationships and solute transport process between basins. However, research on interbasin groundwater circulation is still in its infancy internationally, and the progress achieved is a matter of concern. Progress This study systematically tracks and analyses the literature on interbasin groundwater circulation at home and abroad in the past 20 years and summarizes the existing research progress from three perspectives: formation mechanism, identification methods, and impact assessment. In terms of the hydrodynamic formation mechanism, the study theoretically determines the deviation characteristics between the surface divide, the highest point of the water table and the divide point of groundwater flow systems. Based on the deviation characteristics, multiple interbasin groundwater circulation paths can be separated between rivers.In terms of identifying the interbasin groundwater circulation, a series of real basin cases provide available methods, including the water balance method, basin-scale hydrological model and hydrogeochemical end element mixed model. The methods identify the existence of interbasin groundwater circulation and even evaluate the circulation fluxes, which can improve the recognition of the water balance in the basin. It is also found that the location, size, climate and geological conditions of the basin affect the occurrence and flux of interbasin groundwater circulation.In terms of impact assessment, it is preliminarily found that the interbasin groundwater circulation has an important impact on the assessments of climate sensitivity, state parameters of the Budyko framework and carbon source/sink in the basin. Ignoring its role may lead to obviously incorrect conclusions. Conclusions and Prospects At present, research on the dynamic process and material transport effect of interbasin groundwater circulation is relatively weak. Accurate and quantitative evaluation methods are also lacking. The focuses of future research are to reveal the circulation paths of interbasin groundwater in three-dimensional aquifer space and accurately assess the various impacts of interbasin groundwater circulation.

Keywords

• closed basin
• groundwater divide
• groundwater flow system
• climate-hydrological model
• budyko framework
• carbon cycle