THE COMPARISON OF FUZZY DRASTIC MODEL AND CONVENTIONAL DRASTIC MODEL TO DETERMINE THE MOST APPROPRIATE INDICATOR OF GROUND WATER VULNERABILITY (CASE STUDY: SARKHOON PLAIN AQUIFER)

Introduction Drastic model is an index and overlapping model that has been designed for producing vulnerability scores for different points by combining several thematic layers. Overlapping distinguished methods are the most applicable methods for evaluating vulnerability of aquifers because they are cheap, they can directly reach a defined goal, the used data in the methods are accessible or can be estimated, their final results can easily be described, and they are suitable for managerial decision making. However, ranking system of parameters of this method is an irrational and unreliable system. These classifications are based on Boolean method. If classification is done based on Boolean method, it will cause a zone to displace a story to a higher or lower score with little change which is not acceptable and justifiable. But it seems that one can present a suitable method for classification and ranking using fuzzy theoretical fundamentals compared with Boolean method. In that fuzzy method gives a membership to each theme. This research has been conducted to utilize fuzzy theoretical fundamentals in modeling of drastic hydrogeology parameters. These parameters have inherent uncertainty to determine fuzzy drastic index and compare it with conventional drastic index to obtain the most accurate and suitable inherent vulnerability evaluation index. In this study this index can be evaluated for Sarkhon Zone to find vulnerability evaluation as a guide for managers and authorities as an efficient instrument for taking suitable measures. In this research, the studied zone is aquifer of Sarkhon Plain located in Hormozgan province.