ارزيابي آسيب پذيري كيفي آب هاي زيرزميني با استفاده از منطق فازي، مطالعه موردي : آبخوان هاي حوضه ي آبريز زاينده رود

چكيده انگليسي :

Groundwater Qualitative Vulnerability Assessment Using Fuzzy Logic Case Study Zayanderood River Basin Aquifers Farshad Rezaei f rezaei@cv iut ac ir Date of Submission 9 19 2011 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language Farsi Supervisor Dr H R Safavi hasafavi@cc iut ac irAbstractNowadays regarding to growth of technology human communities development and extension of industrialactivities and the great ration of these affairs in environmental pollution the attention to the environmental problemsof water resources have increased and these concerns and attentions have become multiple by decreasing of healthywater resources in recent years Among present water resources due to less pollution susceptibility and also higherstorage capacity in comparison with surface water groundwater is considered as an important water resource tosupply human water requirements But realizing and control of pollution and also removal of pollution from thisresource are very difficult and expensive So the vulnerable zones must be detected and then must be prevented frombeing contaminated One of the commonest methods in order to evaluate the groundwater contamination is DRASTIC method This method that is applied in this thesis is based on seven parameters that describe hydrogeological settings In thismethod each parameter is assigned a rating and then these ratings are multiplied by the weights assigned to eachparameter based on its importance and after combining with each other the vulnerability index is obtained But inDRASTIC method the Boolean Logic is used to classify and rating the parameters This logic caused someproblems For example with the smallest variation in the parameter value an area is shifted to a higher or lowerclass and finds another rating or the areas that obviously have different values are assigned the same rating and allof these events are not plausible and logical In this thesis In order to eliminate these problems the Fuzzy Logic hasbeen used instead of the Boolean Logic In this method a membership function has been assigned to each parameterand the parameters values as the singleton inputs are entered to the Fuzzy Inference System FIS Eventually afterdefuzzification a defuzzified output as a rating is assigned to the parameter of that area In this thesis also netRecharge parameter that is one of non intrinsic and time variant parameters in DRASTIC method is considered inthree cases Minimum Maximum and Mean So in addition to variations in space the variations in time areconsidered as well This thesis is implemented on Zayanderood river basin aquifers and at last the vulnerability map wasprovided This map generally showed that the areas located in the west of the basin in all the cases are of maximumpollution potential and after that the areas located in the east of the basin are of considerable pollution potential aswell Meanwhile the central areas of the basin in all the cases are of too low pollution potential The results of singleparameter sensitivity analysis showed that the effective weight of net recharge decreases from west to east andgenerally the effective weight of maximum net recharge is more adjustable with its theoretical weight This pointemphasizes on the application of this case in order to calculate the f DRASTIC DRASTIC modified by Fuzzylogic vulnerability index Also the results of map removal sensitivity analysis showed that with removal ofminimum net recharge layer the most extent of the basin has a little variation in the vulnerability index as seen inthe mean net recharge case But in the maximum net recharge case opposite to two previous cases the west of thebasin has a large variation and the east of the basin is of moderate variation and the center of the basin lacks anyvariation Then the SI method applied in order to assess specific vulnerability was used and compared with f DRASTIC model The results showed that in SI model vulnerability

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ارزيابي آسيب پذيري كيفي آب هاي زيرزميني با استفاده از منطق فازي، مطالعه موردي : آبخوان هاي حوضه ي آبريز زاينده رود

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