Study On Groundwater Reservoir Regulation With A

Nowadays, more and more attention was paid on groundwaterreservoir. With the case of the middle reaches of Yinma River, thethesis studies groundwater reservoir regulation to supply more waterfor Changchun city.In winters or drought seasons, surface water can catch littlerecharges in north area of China, so it is difficult for rivers to recoveronce they were polluted. By contrast with surface water, groundwater,with stable quantity and favorable quality, can't be polluted easily. Atthe same time, yield facilities of aquifer can't easily be destroyed byearthquakes or wars, and can supply water continuously and stably in agiven time.Changchun is a city which short of water resources and depends onoutside in water supply. With the analysis of water resources system,the thesis assessed the environment of water supply and emergencywater sources for Changchun city.Research area in the middle reaches of Yinma River lie atsoutheastern Changchun city, which is a irregular area with the centerof Wanchang town, Yongji county and Qijia town, Shuangyang district,total area 682.516km2, locates at intercross area between alluvial plainof Yinma River and Yishu geosyncline.According to analysis of water resources system of research area,there is a greatly change for precipitation in time, surface water'spresent regulating capacity is limited and groundwater development ison a lower level, which leads to frequent emergence of flood disasterand dry damage and lower intact regulating capacity of the system.Based on superimposed model of regression analysis model and timeseries analysis model, forecasting precipitation and we can know fromthe calculation results that, average precipitation is 641.1 mm/a in thearea, minimum is 428.1 mm/a, maximum is 873.5 mm/a, annualprecipitation is center to May to September when average precipitationis 536.2mm, account to 83.6 percent of a year.Regulating water resources of groundwater reservoir in the middlereaches of Yinma River comes from surface water discharge reduction,phreatic water discharge reduction, phreatic water evaporationreduction and precipitation recharge increment. With the satisfaction ofwater consumption in area and discharge to downstream, forecastingwater increment available between 2003 to 2030 is 5.26439 billion m3,average 0.18801 billion m3/a, of which surface water dischargereduction is 3.8549 billion m3, average 0.1377 billion m3/a, account to73.266 percent, maximum is 0.53914 billion m3/a, of which surfacewater discharge reduction is 0.4888 billion m3/a, minimum is 0.05034billion m3, of which surface water discharge reduction is 0, there is nosurface water discharge reduction can be gain in about 1 per 2.5 years.Based on analysis and calculation of groundwater sub-system inresearch area, boundaries of groundwater reservoir in the middlereaches of Yinma River are defined as follow. Northeast boundary isthe breaks between second bottom of Chaluhe River and loess benchterrace, from Nuanquanzi of Guanting town, Yongji county to Chaluhetown of Yongji county. Southeast boundary is mainly imperviousboundary formed by east fracture of Yishu geosycline. South boundaryis recharge boundary between outside hilly country and loess benchterrace, from Jinjia of Yongji county to Changlingzi and Yunshan ofShuangyang district, including entrance of Yinma River andShuangyang River. Southwest boundary is groundwater shed betweenShuangyang basin and Yitong basin. Northwest boundary is westwaterproof fracture of Yishu geocycline. North boundary is dischargeboundary, from Sijiazi bridge of Erdao district to Anzhi farm of Jilinprovince. Below flat boundary is closed boundary. Above flatboundary is water exchange interface. According to different standard,maximal storage of objective aquifer is 2.46 billion m3, minimumstorage in theory is 1.23 billion m3 and maximal regulating storage intheory is 1.2318 m3, optimization maximum regulating storage is0.8212 m3, potential is 0.4980 m3.Artificially groundwater recharge in the middle reaches ofYinma River are such methods as ground penetration, groundwaterrunoff regulation, dam catchments, irrigating penetration and inducedrecharge etc. But for present engineering, 13 mini-type retarding damsand 5 groundwater recharge fields whose recharge capacity is 1470thousand m3/d will be built. Intake engineering includes two types: oneare scattered collection wells net, another are concentrating intakewells for outside area. There will be furnished 8 machine-electricalintake wells and 24 transverse intake wells down Shuangyang River,12 machine-electrical intake wells and 36 transverse intake wells downYinma River, 6 machine-electrical intake wells and 18 transverseintake wells down Chalu River, 26 transverse intake wells surrounding5 recharge fields. There have been over 800 machine-electrical wellswestern Yinma River and over 400 machine-electrical wells easternYinma River. It can be known, from calculative results, thatconcentrating intake capacity is 174.72 thousand m3/d and 49.92thousand m3/a and area intake amount can be regulated.The thesis showed a kind of methods to study groundwaterreservoir form such three sides: water sources, regulated space,artificial recharge and discharge. Boundaries of the groundwaterreservoir were ascertained, ultimate regulated space was be calculated,degree of artificial regulation and environment responds were forecast.For different goals of stable supply water and emergency supply water,the thesis designed different schemes of artificial recharge anddischarge and studied the capacity of groundwater reservoir regulationbased on simulation model.The thesis supplies references for emergency water supply basedon groundwater reservoir and groundwater management in the middlereaches of Yinma River and watershed of Changchun city.