Evaluationof Karst Water Resources In Majiashizui Water Souce Area,xichuan County

The water source of Majiaishizui in Xichuan County,Henan Province is located in the central and western part of the Easter section of Xi chuan-Nei xiang inverted complex monoclinic karst water system,the hydrogeological conditions are complex,and the underground karst fractures are rich in water resources and large in storage.However,the research level of groundwater resources calculation is not high.On the basis of hydrogeological survey of water supply in and around the investigation area,the output method and analytical method were used to evaluate the amount of karst water resources in the water source area,demonstrate the assurance degree of the water source area,and put forward suggestions for the protection of the water source area based on the analysis of environmental problems related to karst water exploitation.The analytical method is mainly used to calculate the allowable mining amount of water resources exploitation,the mutual influence of groundwater resources exploitation and the trend forecast of drop of water level of karst fissure in the future.The natural resources and allowable development of water sources are calculated by using the output method.Through the summary of the field hydrological survey,including survey of the current mining conditions of water springs and karst fissure water and the lateral excretion of rivers,and the calculated results of natural supply resources of water sources and allowable exploitation have certain errors,which can be used as a reference.After analysis and calculation,the amount of natural replenishment resources in the water sources area of Majiashizui is63155.9m~3/d,the allowable amount of mining is 42375.2m~3/d.The analytical method is used to evaluate the allowable mining amount of water resources exploitation,analyze the mutual influence of groundwater resources exploitation and the trend forecast of drop of water level of karst fissure in the future.The permeability coefficient(K)and other related parameters are obtained by three groups of well interference pumping tests and four groups of single well pumping tests.The reliability of calculated parameters is higher and can be used as the basis for the preliminary design of groundwater exploitation in the water sources area.After analysis and calculation,the amount of mining in the water source area of Majiashizui is40906.5m~3/d.Through the comparison of calculation and evaluation between the two methods,the results obtained by analytical method can be used as the preliminary design basis for groundwater exploitation in the water source area.The recommended allowable mining amount for the water source of Majiashizui is 40000m~3/d.The results are of great significance for the calculation of karst groundwater resources under similar hydrogeological conditions.