Conditions Of The Groundwater Recharge And Design Of The Demonstration Experiment In Typical Area Of The North China Plain

In the North China Plain, groundwater resources has irreplaceable strategic position. It plays an important role in aspects of water security, food security and environmental security whether in past, now and future. In the future, economic will develop rapidly. The uncertainty of flood will increase in the context of global climate change. Groundwater recharge conditions will be weakened and destructed, and environmental geological problems closely related to groundwater exploit will increase. Groundwater absolute demand will increase sharply. So, groundwater resources recharge and conservation will have particularly important significance in resolving outstanding contradictions between supply and demand.The paper completes relying on land and resources public project "Groundwater recharge key technologies and demonstration projects in typical area of the North China Plain". Many methods such as data collection and analysis, field surveys and drilling are used. Study area's physical geography geology and hydrogeological conditions are studied. Combined with regional and watershed conditions, necessity of artificial recharge of groundwater is analysed from aspects of groundwater exploitation and environmental geological effects and water wastage and loss. The feasibility is analysed from aspects of recharge water, underground space and infiltration capacity. The previous recharge tests in study area and surrounding are comparatively analysed. Now, the abandoned water from reservoir is concentrated. Large monsoon floods are short and fast. Thick stratum vadose has full storage space. But the surface infiltration ability reduces. The land for recharge is limit. Shallow Wells group with filter devices have greater advantages recharge. Large-diameter wells can increase the area and the amount of the infiltration. Sediment blockage should be minimized. Pretreatment attempts to prevent the block need to be enhanced. Based on this concept, Groundwater recharge system is designed. It includes water treatment system, recharge wells systems, monitoring systems and operational systems.Water supply and treatment system consists of water amount and quality control gates, pipes, treatment pond and prepared recharge pond. It is used to provide controllablel qualified pressurized water for recharging. The Innovation is that the amount of the inflow and discarded water can be controlled flexibly by sliding the control board.Recharge wells system includes water supply pipelines and recharge wells group. It is used to supply water for wells and carry out artificial groundwater recharge. The first innovation is the craft of one pump for multi-purposes and one pipe for multi-uses. The pump can Offers many modes of water supply using fewer pipelines. The second innovation is to solve the problem that the filter material is difficult to wash and only can be used for a short time by making set between filter material and tube wells and let the bottom of the filter lean outside. The third one is the invented recharge-flushing converter. It makes recharging and flushing use one pipe by pushing the piston by water. So the flushing becomes more convenient and well construction cost lower.Monitoring system includes monitors of water quantity, water quality and water level in the water recharge process. The innovation is that water level and water quantity will be monitored automaticly.In the running system, pipeline's water-carrying capacity and the penetrate ability of the filter material by the well will be estimated. The results meet the requirements of recharge. The single well running programs are as follows:natural intermittent recharge, low flow "recharge-flushing", high flow "recharge-flushing", tests for filter material's penetration ability and tests of different pressures recharge. Multi-wells recharge programs are that different combinations of recharge wells according water quantity and quality.Research can provide technical references for land and resources public project "Groundwater recharge key technologies and demonstration projects in typical area of the North China Plain". It has important significance value for recovery and protection of the groundwater resources.