Research On The Programming Of Water Resources In Qian'an County

Qian'an County is located in the low plain of Western Jilin Province which transits from subhumid forest grassland to semiarid and desert zone, where the special geological location makes many entironment problems exist, such as drought, flood, salinization, sand storm, degeneration of grassland, deterioration of water quality.Qian'an County is one of the small counties of Jilin Province, where drought always exists. The drought often occurs in spring, and sometimes in autumn or summer. The mean annual precipitation is 415.5mm, which concentrates during June to September, while the mean annual evaporation is 1849.01mm, which concentrates during April to September. There is no river across the area, and most of the lakes are alkali, some of which are dried up. Since the precipitation is little, with high evaporation and without any rivers, the main water use is from groundwater exploitation in the area.Qian'an County is a lacustrine plain, with the elevation from 130m to 180m. The topography is high in southwest, while low in northeast, with the mean gradient of 1:2400. The southwest part is highland, while the mideast and northeast part are lowland, with many lakes. The stratum mainly includes the Cretaceous system, Tertiary system and Quaternary system. The main two types of groundwater with great value for water supplying are Quaternary unconsolidated confined groundwater and Tertiary fractured confined groundwater. The aquifers consist of sand, gravel, sandstone and siltstone. The total storage volume of groundwater is 3965.24 million m~3. The natural recharge of groundwater is 268 million m~3, of which the 247 million m~3 is from precipitation, and the other is from lateral recharge. The feasible exploitation is 188.02 million m~3. The equalizing results show that the change of storage in 2006 and 2007 indicated negative equalization. The dynamic data of groundwater also shows that the water level declines gradually. The exploitation of groundwater in Qian'an County is so large that great decline of groundwater level caused some cones of depression form in local areas. The natural groundwater quality in confined aquifer is good; however, since the poor water quality from upper layer, the pollution of water quality deteriorates gradually, where the concentration of fluorine, iron and manganese increases. Presently, the Quaternary groundwater has been polluted completely. Because of the poor watertight of pumping wells, the seepage of unconfined water from upper layer becomes more quickly when pumping, which makes some of the Tertiary fractured groundwater wells with good water quality also be polluted. The year of 2006 is seen as the status in quo, and based on the"Outline of the Eleventh Five-Year Plan"of Qian'an County; programming of water use in the year of 2011 and 2016 is set according to different growth rate of economy and population, and different ration standard of water use. The total water use quantity in 2011 will be 172.20 million m~3, of which domestic consumption being 12.78 million m~3, industrial consumption being 41.10 million m~3, agricultural consumption being 111.67 million m~3, livestock consumption being 6.64 million m~3. The total water use quantity in 2016 will be 746.85 million m~3, of which domestic consumption being 14.94 million m~3, industrial consumption being 68.66 million m~3, agricultural consumption being 655.52 million m~3, livestock consumption being 7.72 million m~3. The balance analysis shows that the total groundwater quantity can satisfy the need in 2011; however, since the unbalanced allocation of water quantity, Qian'an County and some other counties are short of water. The discrepancy of water supply and water need will be quite large in 2016, and the feasible groundwater exploitation can no longer meet the need of the development of industry and agriculture of Qian'an County.According to the"Outline of the Eleventh Five-Year Plan"of Jilin Province, three water supply schemes have been designed. Scheme 1: the total quantity of water supply (0.5 billion m~3) from Hadashan Hydraulic Joint Project is only used as irrigation. Scheme 2: the surface water is used for industry, architecture and agriculture. Scheme 3: besides the industry, architecture and agriculture, the surface water is also used for the domestic use in the areas short of water supply, such as Qian'an County. The multiple criteria linear programming model is used to build the optimized allocation model of the water resources to realize the combined utilize of surface water and groundwater, which can achieve the maximum benefit among economy, society and environment. Professional software LINDO6.1 is used to solve the model and some conclusions are drawn out:â‘ the current water use scheme, that only exploit the groundwater can not satisfy the need of the development of industry and agriculture in Qian'an County, and hydraulic project should be got into the saddle;â‘¡a water supply factory with 50 million m~3/a should be built to ensure the economy increase steady. The water used for irrigation should be surface water, and groundwater should be used for domestic and livestock.Since the groundwater pollution problem has been more and more serious, strict hierarchical watertight technology should be taken while exploiting the Tertiary groundwater. To control the industrial and domestic sewage let randomly, drain net should be consummated, and open channel should be impermeable to cut off the direct pollution of organic or poisonous contamination.The paddy field is strictly prohibit to be developed before the Hadashan Reservoir has been finished, and water use management should also be strengthened by building strict management system. Measures should be taken to strength the protection of the water source and the monitoring of the groundwater. The total quantity should be controlled, and different quality of water should be supplied to different usages. The recycling of industrial water should be increased, and the equipment of water usage should be improved to reduce the water use of unit product. The structure of agriculture should be adjusted to control the area of crops which may use large quantities of water, and water saving irrigation technology should be taken to improve the recycling rate of water use. Only in these ways can the protect ecological environment which has a signification to realize the sustainable utilization of water resources and the sustainable development of economy for Qian'an County.