Performance comparision of Information Value and Density Area Methods for Spring potential in Ghurchay Watershed, Golestan Province

Developing a suitable model for effective management and sustainable use of groundwater resources is critical and prepared springs potential map allow us to provided extractable water by spending less of time and cost. In this study, the Gharechay watershed was slected with 248.1 km2 area. Then distribution map of springs (dependent variable) was prepared. Also information layers as slope direction, slope gradient, slope length (SL), profile curvature, curvature of plain, topographic wet index (TWI), stream power index (SPI), geology, fault density, distance to fault, elevation, drainage density, distance from river, land use, distance from the road, soil texture, soil hydrologic group and vegetation density as the independent variable prepared and were digitized in GIS environment. Of the combination of independent variables and the dependent variable, the value of spring in each class was calculated and weighted classes based on the as Information Value and Density area of statistical models were used. Finally, with the obtained weighted maps and sum them zonation spring map in two models were obtained. The results of models using the Relative Operating Characteristic (ROC), and Quality Sum (Qs) shows that information value method with ROC=0.981 and Qs=0.488 than the density area with ROC=0.851 and Qs=0.459 is appropriate for zoning resources ground water springs in this area. Also, based on information value method and density area 94.1% and 65/51% respectively of the study area are high and very high potential to have an incidence springs.