| High plain in the central of Jilin province included Changchun and Siping, which is the national important commodity grain producing area.It is not only relatively concentrated area of population and economy in Jilin province, but aslo the excessive zone of low western plains of east mountains, is important groundwater runoff approach to eastern mountain, is important groundwater runofft supply source of west low plain, and the area as economic zone in Jilin province,existed cities with serious shortage of water resources, and some environmental hydrogeological problems,such as the excessive exploitation of groundwater,deterioration of water quality,so the study area is a key to study of groundwater circulation and the evolution of water environment. in Jilin province.The paper from three aspects launches the research,the space-time evolution characteristics of groundwater resources amount, space-time evolution characteristics of groundwater flow,space-time evolution characteristics of groundwater chemistry,regarding hydrogeology,groundwater dynamics, geological statistics theory as a guide, adopted the recharge method calculation and summarizes the groundwater resources in time and space evolution characteristics; using statistical and geostatistical methods summarized the groundwater dynamic characteristics of temporal spatial evolution; with the method of statistics, typical section method, graphic method, the linear graphic method and factor analysis method summarized the temporal and spatial evolution characteristics.of groundwater chemistry in the study area.Achievements are shown as follow:1.Space-time evolution characteristics of groundwater resources amount:In time,groundwater resources evolution shows synchronous changes trend roughly with precipitation changes, and showing a periodic evolution trend, groundwater resources evolution in 2002-2014 exist 5 increased years and 4 reduced years, 5 increased years are2003, 2005, 2008, 2010 and 2012, 4 reduced years are 2004, 2007, 2009 and 2011;The administrative area, water resource fourth level division of water resources, Changchun,Siping, the region’s groundwater resources amount is close to years of average value in2002-2014, and the annual calculated value fluctuated change over the mean of many years.In space, many years average amount of groundwater resources in high plain of central Jilin province is 2.71718 billion m3, the ratio of precipitation infiltration recharge is 91.5%,the ratio of surface water recharge is 8.5%; In terms of administrative divisions, the total amount of groundwater resources in Changchun area was 1.65285 billion m3, the total amount of groundwater resources in Siping area was 1.06312 billion m3; In terms of topography and geomorphology, the total groundwater resources in the plain area of the study area was2.41406 billion m3, and the total amount of groundwater resources in the hilly area was0.30312 billion m3; On the watershed division, the total amount of groundwater resources in the Songhua River basin is 1.81425 billion m3, the total amount of groundwater resources in the Liaohe River Basin is 0.90293 billion m3;average supply module in the study area is71000 m3/km2, the supply module for an average of Changchun region is 83000 m3/km2, the supply module for an average of Siping district is 66000 m3/km2.2.Dynamic space-time evolution characteristics of groundwaterDuring the year, wet-dry season water level difference range from-2.44 m to 4.53 m,median is-0.06 m,the zone proportion of drop water level is 49.47%, the rise zone proportion is 50.53%;Years of water depth widespreadly increased in the whole 1991-1996,1996-2001, namely water present a continuous downward trend, water level drop 0.5m in 1991-1996, water level drop 1.6 m in 1996-2001, only the local mean value and the median difference are negative,that buried depth of groundwater turns small, the water level rise.3.Space-time evolution characteristics of groundwater chemistry:In terms of water chemical composition, in 1992 and 1996, there are some small salt water areas in the distribution of isolated island., in 2001, there was a slight increase in the area of brackish water in the whole area; total hardness existed a small range of points in 1996, in1992 and 2001 the total hardness appreared surface excessive, ammonia and nitrogen present a good evolution trend, nitrite nitrogen appeared a large excessive area in three years, and showing a good evolution trend; nitrate nitrogen present a small excessive area over three years,and showing a good evolution trend.From the qualified rate of water quality evaluation results, each year diving percent of pass is in the order of 1992 < 1996 < 2001, showing a good development trend on whole;confined water quality qualified rate was 84.6% in 1992, confined water percent of pass is 76.9% in 1996, the confined water percent of pass is 79.2% in 2001, the confined water quality evolution phenomenon is not obvious, from 1992 to 1996, in a certain water quality deterioration, water quality from 1996 to 2001, showing a small good trend;inhydrogeology partition perspective,21 partition has 10 partitions present a "continuous variable good" development trend, there are three partitions present a "continuous variation bad", there are six partitions present a " good-bad variation ", there are two partitions present a " bad-good variation ";Chemical classification of groundwater in the area that groundwater anionic type mainly is given priority to with bicarbonate root, bicarbonate, chloride, sulfide, chloride,bicarbonate root scattered, cationic type are mainly composed of calcium, calcium and magnesium.Groundwater chemical factors affecting factors of human activities in 1992, 1996, 2001 three period appear less human activity effect trend, but in terms of the three period of natural factors(including aqueous medium conditions, water-rock action etc.) apprar enhancement trend.In this paper, starting from the actual needs of the management of groundwater resources, fully analysising the hydrologeological conditions,the social economic conditions,physical geography,the meteorology and hydrology,concluding a comprehensive analysis for the temporal and spatial evolution characteristic of groundwater,summarize the distribution characteristics of groundwater spatial elements.The results provide a scientific basis for reasonable exploitation and planning of groundwater resources and the conservation of water environment in Jilin Province central plain area. |
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