Weihua Xiao

Simulating the hydrologic cycle in coal mining subsidence areas with a distributed hydrologic model.

Large-scale ground subsidence caused by coal mining and subsequent water-filling leads to serious environmental problems and economic losses, especially in plains with a high phreatic water level. Clarifying the hydrologic cycle in subsidence areas has important practical value for environmental remediation, and provides a scientific basis for water resource development and utilisation of the subsidence areas. Here we present a simulation approach to describe interactions between subsidence area water (SW) and several hydrologic factors from the River-Subsidence-Groundwater Model (RSGM), which is developed based on the distributed hydrologic model. Analysis of water balance shows that the recharge of SW from groundwater only accounts for a small fraction of the total water source, due to weak groundwater flow in the plain. The interaction between SW and groundwater has an obvious annual cycle. The SW basically performs as a net source of groundwater in the wet season, and a net sink for groundwater in the dry season. The results show there is an average 905.34 million m3 per year of water available through the Huainan coal mining subsidence areas (HCMSs). If these subsidence areas can be integrated into water resource planning, the increasingly precarious water supply infrastructure will be strengthened.

The Development and Application of WACM

This paper is about the necessity of developing the WACM (Water Resources Allocation and Cycle Model), its developing process, basic frame and application. WACM couples generalized water resources rational allocation model with water cycle model affected by nature and human. The former model is based on the simulation of water supply, water use, water consumption and drainage, whose target is to minimum water deficit in research region. The latter model sets up water balance model and water dynamics model from the perspective of water balance and water dynamics, which includes the chains of evaporation, precipitation, exchange between soil water and ground water, runoff and converge. The water balance model mainly simulates cycle, change and conveyance of water quantity, but the dynamics mechanism is not considered. The dynamics model is based on water dynamics mechanism, which supplies timely water cycle response information of generalized water resources allocation, to achieve the dynamic allocation and simulation on the water resources allocation and water cycle process. The WACM can couple with economy and ecology models to study and analyze the effect of water resources development and utilization on economy and ecology. WACM is developed and improved in the practice, which has been successfully applied in generalized water resources rational allocation of economy ecosystem, efficient utilization of regional water resources, the management and control of water resources, the analysis of regional water saving potential and threshold, the quantitative relationship of water saving between resources and irrigation, the check computation of water resources on water utilization and the determination of its threshold, etc. The application effect of WACM is satisfying.