Study Of Groundwater System Vulnerability Assessment In Deyang City

Based on the at home and abroad research results.Further studied the concept ofGroundwater system vulnerability combined with Groundwater system concept.thenreclassified the influence factors on the vulnerability from the perspective ofgroundwater system. Acorrding to the specific conditions of deyang city, Assessmentthe single vulnerability of deyang city by ground line gradient, aquifer lithology,characteristics of vadose zone, aquifer thickness, water-rich degree of aquifer,groundwater depth, specific yield of aquifer specific yield, precipitation rechargecoefficient and groundwater exploitable resource modulus, etc. a total of ninefactorsvulnerability evaluation of individual, and among them are6factors ingroundwater quality vulnerability,5factors in groundwater quantity vulnerability.Atlast, Assessment the quality and quantity vulnerability use the point count systemmodel, Draw the following main conclusions:Groundwater system vulnerability is one of thefeatures of groundwater system,it’s the ability of resist changes and keep their original state when accept environmentincentive.such incentives include the water quality ande quantity, but also includingthe benefical and harmful.When only accept the environment incentives, thegroundwater system more performance of its inherent ability to resist change, thistype of vulnerability known as the intrinsic vulnerability;Consider human activities onthe basis of natural factors,the groundwater system more reflects the ability to resistthe change in human actives,such vulnerability is known as the specificvulnerability.there are two side of groundwater system vulnerability,one is qualityvulnerability,the other one is quantity vulnerability.they have generality,and havecharacteristics.At last,reclassified the influence factors on the vulnerability from theformation, movement, discharge, storage of groundwater,pollutants and others.There is certain connectivity between vulnerability partition and the characteristiscs of ground recharge, runoff, and disrecharge.①the groundwaterdischarge area have higher qualityvulnerbility and lower quantity vulnerability,②Thequality vulnerability is high in groundwater runoff area, but lower in quantityvulnerability.③Groundwater recharge area have higher quantity vulnerability andlower quality vulnerabilitiy.Selected groundwater slope, aquifer lithology, feature of unsaturated zone, aquiferthickness, aquifer water yield proprety, depth to groundwater, aquifer specific yield,infiltration coefficient of precipitation,moduleof groundwater allowable withdrawal9factors. Evaluation the single and comprehensive intrinsicvulnerability in deyang citywith quality and quantity two sides.Comprehensive evaluation shows that, the higherand high quality vulnerability area in deyang city is about113.92km2,51.6%of totalarea, low and lower vulnerabiltiy area is about66.98km2,30.3%of total area.Highand higher quantity vulnerability area is about65.53km2,29.7%of total area, low andlower vulnerabiltiy area is about109.66km2,49.7%of total area.