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I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />zone materials. This type of evaluation, being based on multiple map interpretations, has <br />a limited resolution and was designed on a regional basis. However, the region that Sites <br />D, P and Q are located within is almost entirely delineated as being of the highest level <br />of groundwater contamination suscept~ility. Geologic data from the EIS soil borings <br />supported the MPCA report findings. Using this suscept~ility data as a guideline would <br />indicate that this region would not be conducive for locating suitable solid waste disposal <br />site. <br /> <br />DRASTIC Index <br /> <br />Another method of evaluating groundwater impact potential is by using the DRASTIC <br />Index as developed by the national Water Well Association and the U.S. EPA. This <br />system uses hydrogeologic settings to evaluate and rate seven parameters that affect <br />groundwater pollution potential. The seven rated parameters and weight factors used in <br />calculating the DRASTIC Index-are: <br /> <br /> Parameter Weight <br />1. Depth to water 5 <br />2. Recharge, net infiltration 4 <br />3. Aquifer type 3 <br />4. Surface soil type 2 <br />5. Topography 1 <br />6. Impact of unsaturated zone 5 <br />7. Conductivity of the aquifer 3 <br /> <br />Using applicable data from the EIS Hydrogeologic Site Evaluation report, the three sites <br />were scored according to the DRASTIC Index and criteria as shown in Table 2 The <br />individual parameter weights are set by the EPA/NWWA in the DRASTIC manual. The <br />parameter ratings were taken from graphs in the DRASTIC manual using site specific <br />hydrogeologic data from the EIS report. These ratings were multiplied by the weights to <br /> <br /> <br />