alireza oliaye

Assessment frequency of springs has become an important issue for land use planning, especially water resource identification and environmental protection.The purpose of this study is to produce a spring occurrence potential map in Bojnourd Basin, based on a logistic regression method using Geographic Information System (GIS) and remote sensing (RS). The locations of the springs (359 springs) were determined in the study area. In this study, 14 effective factors including spring were used in the analysis: lineament density, distance to lineament, distance to drainage, drainage density, normalized difference vegetation index (NDVI), profile curvature, tangential curvature, surface rate, vector dispersion, precipitation, elevation, geology, aspect and slope. Binary logistic regression coefficients of the variables by selecting 300 spring randomly. 59 another spring were used for validation that 80.6% of the springs were correctly predicted. The accuracy of the model was measured using ROC curves which showed that accuracy is 86.6 percent which indicates that the model shows high accuracy in the analysis of spring occurrence potential in the study area. The results showed that the distance of lineaments, distance of drainage, drainage density, vegetation index, profile curvature, tangential curvature, vector dispersion, precipitation and slope have the greatest impact on the occurrence of springs. Finally, spring occurrence potential map was divided into four probably classes of very low, low, medium and high. According to the survey results, this method can be used to identify sources of groundwater in karstic zones and has important role in better management of the karstic Basins.

Increasing or decreasing of the flow rate has the direct impact on surface water resources and the management of them in each region. According to this، in the present study، monthly، Mann-Kendall non-parametric and sen’s methods were used to declare positive or negative flow trend، and also Pettitt test was implemented for detection of its change points and abrupt shifts in 12 gauging stations in Fars province during 1972-2011. Furthermore، TFPW approach was used in order to decline the effects of autocorrelation and serial correlation on the Mann-Kendall test. The results of Mann-Kendall test and sen’s method illustrated the decreasing trend for all stations. Also the results of Pettitt test revealed that in four of twenty stations، change points had occurred between 1998 and 1999. Pol khan station (That is located at the end of Kor river)، with decreasing 15. 942 (m3/s) in the mean annual stream flow between two periods (per change point in comparison the post-change point)، and also statistical Mann Kendall (z=-0. 251) and slope (-0. 513)، has the most dramatic change and decreasing trend.