Suitable Site Selection of Fog Water Harvesting Based-On RS Data in Upstream of Vazrud Watershed in Iran

Fog is a potential source of water that can be collected and used with new technologies. If we used simple and low-cost harvesting systems, fog can be mentioned as suitable option to provide drinking water in the World. On the other hand, remote sensing applications have been proven in water resources management and detection of cloud and fog. The present study was carried out to determine the prone-areas for fog-water harvesting in the upstream of the Vazrud Watershed (located on the highlands of Alborz) using remote sensing technique. For this purpose, 17 environmental variables were used. The remote sensing variables (based on Landsat satellite imagery) included land use, surface temperature, and cloudy maps. Climate variables are included leeward effect, windward effect, daylight anisotropy heating, effective air flow heating, sky view factor, wind effect. Hydrological variables are included stream power index and topographic wetness index. Physiographic variables are included DEM, slope, aspect, curvature, catchment area and terrain ruggedness index. All above mentioned variables with the SDMs package in the R program that include 12 models (BRT, CART, FDA, GAM, GBM, GDM, GLM, MARS, Maxent, MDA, RF and SVM) as well as 190 ground control points using GPS-Garmin-76CSx were used as auxiliary data to prepare spatial distribution of fog-water harvesting. In order to evaluate above mentioned models, the ROC curve was used in the R program. The results based on ROC curve indicated that BRT, GBM, Maxent, RF and SVM models were selected as final models (high accuracy) for preparing a fog-water harvesting map. Therefore, the above models were used to prepare the Ensemble model. The spatial distribution of fog-water harvesting map based on the Ensemble model showed that the east, southeast and south of the Vazrud Watershed have the most suitable potential for water harvesting. Also, the areas with more than 2000 meters above sea level are the best fit for the extraction of water from fog, which are located in the southern parts of the basin.