Research On Evaluation Of Groundwater Resources And Sustainable Utilization Of Water Resources In Jixi City

Jixi City is located in the southeastern of Heilongjiang Province and the upper Muleng River,is located in the department of Wandashan and Laoyeling.Groundwater is the main source for water supply in Jixi City.There is water resources short in the study area that total water resources is 37696.1×104m3,and that at present the water resources perperson is only 409.74 m3/a,which is one fifth of the country(2220m3) and lower than the internationally recognized standards of 1000m3 of severe water shortage. Water shortage in Jixi city has been of long standing,including water quality-induced water shortage,resources water shortage and engineering water shortage. Recently years,because of excessive pumping of groundwater.There emerge some environmental geological problems in local area,such as cone of depression,dewatering of aquifer,deterioration of groundwater quality,mine water bursting and so on. Therefore,evaluation of groundwater resources in jixi city, analysis the status of water resources development and utilization, the calculation of the exploitation of groundwater resources and the potential analysis of the exploitation,to raise the countermeasureso of sustainable development and utilization of water resources are very necessary.The range of groundwater resources evaluation is the whole Jixi City,where including low mountain-hill region,with the area 2208.5km2.The object of groundwater resources evalution is hill area bedrock fracture water and intermountain basins,hill valley loose rock pore water. The formulas of groundwater dynamics and water budget method are used to assess the groundwater resources in this thesis. According to landform genesis types,various river basin or water system and groundwater type,the study area is classified as 4 calculation area:Mangniu river(Ⅰ),Didao river(Ⅱ),Muleng river mainstream(Ⅲ),Huangni river(Ⅳ). On the basis of the river system characteristics,the study area is further divided into 15 sub-area calculation. That is divided into 49 calculation section based on groundwater type.Selecting data serie of precipitation and evaporation from 1900～2007,average annual situation and phreatic evaporation are calculated. The quantity of available groundwater exploitation is calculated with the method of expoitation coefficient.The average annual available groundwater exploitation quantity in the area is 7455.4×104m3/a , groundwater exploitable modulus for 3.4×104m3/a.km2.The water quality of 26 groundwater samples in study area is analyzed by the way of Piper Diagram in virtue of Aqua Chem software.The results show that water-chemical components are comparatively complex in this area.For the cation,Ca2+ is predominant component,Mg2+ and Na+ are the second;Foe the anion,HCO3- is the primary component. The quality of groundwater environment of the study area is assessed with the method of synthesis assessment. According to the calculated results,the groundwater in study area is mainly of classⅢ,IV or V. The groundwater of classⅢis distributed in northern pediment tableland and southern basalt platform. The groundwater of class IV is mainly distributed in the Muleng River Valley plains,Mashan District and Lishu District;The groundwater of class IV is mainly distributed in intermontane structure basin,the urban area of Mashan District,Didao district and Jiguan district, a number of coal mine areas.According to borehole data and other geologic and hydrogeologic datas in the urban area of Jixi city,the geologic structure model is established by GMS software,and the distribution of aquifers in study area is confirmed. On this basis,the variation of groundwater flow net in the area is predicted with GMS software. The numeric groundwater model is identified and validated firstly accoding to the dynamic data of groundwater level from April 2003 to December 2003. The groundwater level is fitted well, showing the generalization of the structure and boundary of aquifers and the selecting of hydrogeologic parameters are proper, which can truly reflect the characteristics of aquifers, then the model can be used to predict the water level. The variation of groundwater level in study area is predicted according to 6 different programs. The prediction result shows that the variation of groundwater level is mainly influenced by human exploitation. When a decrease of 2% of production after the May 2008 of the flow field as the initial flow field prediction the initial flow field in May 2010 .Then the depression gradually slows down, and the cone of depression is becoming stable.Multi-target linear-weighted function method is selected to assess the general index of sustainable utilization of water resources in Jixi City in the year 2007,and then the weight of target is determined by the way of AHP.In the present year (2007) the comprehensive index of sustainable utilization of water resources is 0.354,which indicates that the utilization is weak and goes against the sustainable utilization of water resources. The rate of development and utilization of surface water resources is lower, water reuse efficiency in industry is only 45%,these constitute major reasons.water is supplied mainly by over exploitation of the deep phreatic water ,which enlarged descending funnel of deep phreatic water and brings on a series of eco-environmental geology problems.Fuethermore ,it is also associated with the reusing rate of the treated wastewater water saving irrigation rate.Other factors,such as the city development level,public water-saving consciousness,and the devotion of water research and development personnel and hydraulic engineering outlay,alsso exert an influence on that.The groundwater resources and allowable exploitation quantity are limited in study area,but transit water quantity is up to 106300×104m3,and the developmet utilization rate is low,so the potential for development of surface water is great.It is suggested that water resources projects on the crossing rovers be constructed to make the best use of the crossing surface water resources on the basis of groundwater resources rational development.Through optimized use and management of water resources,the long-term target that wter supply will meet the need of the area and enhance the sustainable use of water resources.