| The increasing water shortage has become one of the most important constraints of socialdevelopment for the City of Beijing. Owing to the limited water resources, there will be inevitablewater shortage before the water-diverting project from Changjiang River being put into use in2010 in Beijing. It is essential to make good use of the limited water resources to solve ormitigate this problem. The conjunctive use of surface and ground water, which means therational allotting and storing of water resources, may ease the uneven distribution of waterresources regarding both time and location, and ensure the safety of water supply in the city. The alluvial fans, which consist of the most part of the plain area of Beijing, are mainlymade of course Quaternary sediments. The groundwater stored in the aquifers of the alluvialfans is much more than that stored in the surface reservoirs in Beijing, and the water quality isalso much better. At present, groundwater accounts for about 2/3 of the sources for watersupply in Beijing. The groundwater is very important in ensuring the safe water supply for thecity, especially in successive dry years. The upper and middle parts of the two most importantalluvial fans, which are the Yongding River and Chaobai River, has always been the main watersupply sources, and are taken as two large groundwater reservoir. The long-term overexploitation of groundwater has created vast storing capacity in the alluvial fans. There are a few surface reservoirs in the City of Beijing, such as Guanting Reservoir, MiyunReservoir, Huairou Reservoir and Dashuiyu Reservoir. In all of the reservoirs, the MiyunReservoir is the biggest and its water quality is also the best, and the Guanting Reservoir thatused to be another important water supply source for Bbeijing, can only be used for industrialwater supply recently because of its contamination. These reservoirs can be used conjunctivelywith the groundwater system by means certain facilities. In the paper, the upper and middle parts of the two most important alluvial fans is studiedfor the conjunctive use of water resources, and the working area is 333km2 and 391km2respectively. After investigation in the past several years, considering the experience of artificialrecharge technique in the past, it is found out that there are three kinds of sites for groundwaterartificial recharge, taking into account of the location of the surface reservoirs and groungwaterreservoirs. They are (1) river or channel courses that are dried up; (2) sand pits and (3) bigdiameter shaft. In the paper, the plan for the conjunctive use of water resources in composed of two parts:(1) the alluvial fan of Yongdong River and (2) the alluvial fan of Chaobai River, taken intoaccount of the surface water sources, the quality of surface water, the exploitation ofgroundwater and the storage capacity of the groundwater system. It is calculated that thestorage capacities are 6.24×108 and 6.0×108m3 for the Yongding river area and Chaobai Riverarea respectively. 1. The plan for the area of the Yongding River The infiltrate fields include the bed of Yongding and Nanhan River, the sand pits, DaningReservoir, Daotian Reservoir as well as the large-diameter wells in this area. The channels of water transferring are Yongding River, Nanhan River, Yongding Canal,Jing-Mi Channel and the pipeline of transferring water from east to west. The facilities of waterconservancy project are excellent and the most them can be utilized. The project is divided into 4 parts: Nanhan Project, Yongding Canal Project, Yongding River　 ５３　Project and the Reservoir Project in the plain area. The total capacity of infiltrating is 8.1767Mm3/d (94.64m3/s). 2. The plan for the area of the Chaobai River The infiltrating fields include rivers, sand pits, canals and reservoirs in Chaobai River areawhere water can be taken...
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