Groundwater resource evaluation and development in affected zone of downstreams of the Yellow River

The paper focuses on groundwater evaluation and development in the AZYRD(Af-fected Zone of the Yellow River Downstream),the section in Henan province.Since the1970s,the constant cut off of the downstream s of the Yellow River and the aggra vated pollution prob-lem have led to shortage of water supply which seriously threatened the irrigation area and cities in Henan Province along the Yellow River.Reasonable development of groundwater becomes more and more important for this region.The study area is an alluvial plain of the Yellow River,which consists of a phreatic aquifer and several confined aquifers in an area of about 10 4 km 2 .The main recharge comes from infiltration of rainfall,irrigation ditches and Yellow Riv er runoff.The main discharges are evaporation and extraction from the groundwater system.The current groundwater exploitation is about 1.152×10 9 m 3 /a from shallow and deep aquifers.A3-D groundwater flow model is built with FEFLOW to simulate and forecast the aquifer re sponses to different conditions for groundwater development.The model estimates the average recharge rate of groundwater in this area is about 2.835×10 9 m 3 /a and the security yield is about 1.943×10 9 m 3 /a.Nine sites are selected as prospective large-scale pumping-well-fields and the hydrogeological conditions of each site are described in brief.On condition that the prospective increased total pumping rate is0.486×10 9 m 3 /a,the modeling results can indicate:(1)the maximal drawdown in the center of pumping cone is less than20m;(2)the groundwater table tends to be stable within5～10years;(3)the regional groundwater flow does not change;and(4)62.58%of the pumping rate will be recharged from the Yellow River runoff.Taking the aquifer as a huge adjustable storage for Yellow River runoff to groundwater recharge and exploitation,the surface water use amount can be increased,the water quality can be improved and the wa-ter treatment costs reduced.At the end of this paper the countermeasures for sustainable groundwater development are discussed.The research results show that the Yellow River plays an important role in surface water-groundwater ecosystems.The paper also pointed the importance of protecting the wetland s in AZYRD.