Evaluation Of Groundwater Resources In Tokyo Towns

Water is an important natural resources for human survival, and with the increase in population and the development of human society demand, how the rational use of water resources problem has become the current international problems need to solve.This paper is to achieve the sustainable development of groundwater resources by Tokyo Town, to do a detailed evaluation of groundwater resources in urban areas, including:analysis of the hydrogeological conditions. Tokyo town law of groundwater dynamic change analysis and partition of the quantitative evaluation of groundwater resources in the area, and the comprehensive development and utilization of groundwater resources is analyzed.In the water resources evaluation by using the average distribution of well and mining coefficient method in the process, get the investigation of groundwater allowable exploitation quantity was 709.25 × 104 m3/a, the region accounted for 82.1% of the amount of groundwater recharge, groundwater allowable exploitation modulus of 6.56 × 104 m/km2· a, so the groundwater allowable withdrawal is guaranteed. Iron, manganese in the survey area, the mainland has been detected in water, exceed the standard rates were 30% and 60%, the highest content of iron, manganese only 0.31mg/L the highest content of only 0.26mg/L, are lightly polluted, is formed by the native environment, and can be easily removed; total hardness and pH value of individual exceed the standard may be caused by man-made point pollution. Which can determine the exploration of groundwater water quality is better, in the use of groundwater for drinking water source, for iron and manganese processing can be rest assured to drink. Specific survey are as follows:(1) The survey area is located in the southeast of Zhangguangcai mountain valley plains, Mudanjiang, is in the temperate continental monsoon climate, annual average precipitation is 530mm, the precipitation infiltration and irrigation infiltration recharge is the main recharge sources of groundwater in the area, area of Quaternary loose deposits exist pore phreatic water, confined water and confined water, buried clastic rocks exist pore fissure water.(2) In the region of a terrace of Quaternary aquifer is thin, shortage of groundwater, the water rich and poor. The total average annual groundwater recharge quantity was 244.18 × 104 m3/a. permit extraction volume is 195.34 × 104 m3/a. The two terrace of Quaternary aquifer of sand and gravel. soil containing high, medium water rich, single well yield for 500-1000 m3/d, groundwater recharge is 530.36 × 104 m3/a. extraction volume is 450.81 × 104 m3/a. In the group of Cretaceous clastic rock pore fissure phreatic water rich medium, single well yield for 100-500 m3/d. groundwater recharge is 90.14 ×104 m3/a, extraction volume is 63.10 × 10 m3/a. District level order two terraces of Lower Cretaceous clastic rocks, sandstone and clay wave group at 100m depth water storage condition is poor, lack of centralized water supply significance.(3) The groundwater quality is better, the primary iron and manganese exceed the standard, not affected by the chemical type of water pollution area for heavy calcium carbonate and calcium carbonate, magnesium based water, salinity is less than 0.5g/L, and belongs to the low mineralized water. But sporadic areas suffered mild pollution, as well as the quality of drinking water, irrigation water quality better.(4) Control of groundwater exploitation and comprehensive utilization of water resources, implement, with guarantees on the Tokyo urban economic development.