Groundwater Circulation And Evolution Pattern In YiLi-GongNaiSi Valley Of XinJiang Autonomous Region

Yili- GongNaiSi Valley is located in the important city Yili autonomous prefecture of Northwest China. It occupies a very important position in the national implementation of the "road" economic strategy. Requirements for water resources and rapid development of region economy increasing, only rely on surface water has not been able to provide water resources guarantee for area agriculture, industry, service industry and so on. Yili-GongNaiSi Valley is a groundwater resources endowment and mountain valley considerable, as ever in the region to carry out the hydrogeological work less, resulting in hydrogeology for a study area of understanding degree is low, the development and utilization of groundwater resources and the lack of scientific planning. Therefore, development of groundwater circulation and evolution law research areas to enrich the understanding of hydrogeological conditions in the region is very necessary.In this paper, with the theory of regional groundwater circulation as a guide, the integrated use of groundwater dynamics, hydrogeochemical, environmental isotope hydrology and groundwater flow numerical simulation theory and technology, carried on the analysis to the Yili GongNaiSi Valley groundwater circulation and evolution pattern, making some achievements and recognition:(1) Yili-GongNaiSi Valley is a rift valley, the valley, Quaternary sediments in uneven thickness, ranging from 300 to 800 meters. Vertically, from the mountain to the valley area, groundwater from the mountains(recharge) after the piedmont alluvial plain(Yili river runoff area) excretion(drainage area). Laterally, before the Turks River empties into GongNaiSi Valley, for a single aquifer structure, multi-layer structure in YiLi river, Groundwater is generally from west to east flow.(2) the water chemistry research results show that, the vertical, chemical types of groundwater from north to south in order to HCO3-Ca,HCO3-SO4-Ca-Mg,, HCO3-SO4-Ca-Mg-Na based. Laterally, chemical types of groundwater water chemistry types from east to west of HCO3-Ca, HCO3-SO4-Ca-Mg, HCO3-SO4-Ca-Na. Look on the whole, the mineralization degree of groundwater are basically less than 1g/l and the quality of groundwater is good.(3) isotopic analysis indicates that the main recharge source area is atmosphere precipitation, groundwater renewal rate of diving is different in different geomorphic units, tilt groundwater gravel plain in strong renewal rate in 5-10 years, in the gently inclined pebbly fine soil plain and alluvial proluvial fine soil plain water age update rate 30-40 years. Compared with diving, confined water(depth is >200m) 14 C test results show that the long residence time of groundwater in the aquifer, the groundwater age in 20000 years.(4) Through the establishment of regional groundwater flow numerical model, depicting the evolution of groundwater dynamic field mainly developed tertiary groundwater circulation system,respectively, for the local groundwater flow circulation system, middle underground water circulation system and regional groundwater flow circulation system. The three groundwater runoff zones, which are the shallow strong runoff area(>0.5m/d),the middle runoff area(0.1~0.5m/d)and the deep weak runoff area(<0.1m/d).(5) there are two kinds of water circulation pattern typical research area: one is from north to south, the mountains of atmospheric preciptation and snow melt water from rivers, rivers due to the formation of leakage in bedrock fissure water. With the changes of sedimentary environment, terrain slope slow down, a portion of bedrock fissure water in the piedmont thrust springs and the exposed surface of alluvial fan, and also a part of the groundwater continued to move forward, and ultimately excretion from the YiLi River. The second is something up, the eastern mountain is the highest elevation point in the study area, affected by terrin, in the eastern mountain area of about 90% of the precipitation or snowmelt runoff in the form of a westward moving, import GongNaiSi River, about 10% of the atmospheric precipition and snow melt water to groundwater.