Hesel Pouri; Vahedberdi Sheikh; yeganeh hasan
Abstract
The present study has been carried out aiming at suitable site selection for rainwater harvesting across the northern rangelands of the Aq Qala district to supply drinking water for grazing livestocks using the effective criteria and multi-criteria decision support system. The rainwater harvesting suitability ...
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The present study has been carried out aiming at suitable site selection for rainwater harvesting across the northern rangelands of the Aq Qala district to supply drinking water for grazing livestocks using the effective criteria and multi-criteria decision support system. The rainwater harvesting suitability map was created by integrating the multi-criteria evaluation (MCE) technique and standardization (fuzzification) of continuous raster data within ArcGIS. To determine the suitable rainwater harvesting areas, the weighted linear combination (WLC) was applied in the range of 0 to 1 using the multi-criteri evaluation (MCE) within the ArcGIS and and the data of various criteria including distance to water source, distance to cattle post, stocking density, normalized difference vegetation index (NDVI), distance to road, slope percentage, distance to settlement and soil texture. The result indicated that about 2950 ha (~5.2%) of the study area have a good suitability for implementation of rainwater harvesting systems to supply water for grazing livestocks. The results of questionnaire survey revealed that about 70% of 107 stakeholders of the rangelands are highly willing to install and utilize rainwater harvesting systems, but high cost of installing is considered the main hinderance.
Ataolah Kavian; 1 1; 1 1; 1 1; 1 1; 1 1; 1 1
Abstract
Small and portable rainfall simulators are essential tools in study of soil erosion and surface hydrology and it provide to repeat natural rainfall characteristics. In addition to the introduction of this device, calibration tests were performed including nozzles discharge evaluation, uniformity test ...
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Small and portable rainfall simulators are essential tools in study of soil erosion and surface hydrology and it provide to repeat natural rainfall characteristics. In addition to the introduction of this device, calibration tests were performed including nozzles discharge evaluation, uniformity test over the plots and raindrop size distribution. The results of nozzles discharge calibration showed that two nozzles discharge at 20, 40, 60 and 80 KPa pressure are similar and there isn't any significant difference between them. To achieve the optimum uniformity of simulated rainfall over the plot uniformity test was performed with changing nozzle distance (50, 60 and 70 cm) and oscillation of nozzles (30, 45 and 60 degrees) at constant operational pressure of 60 KPa. The results showed that the uniformity coefficient at 2m2 plot obtained from 57% to 61% and rainfall intensity changes from 48 to 101 mm/hr. The results of high velocity photography revealed median diameter of raindrop as 2.4 to 2.6 mm.
Shafagh Rastgar; Hossein Barani; Ali Darijani; Vahedberdi Sheikh; Jamshid Ghorbani; Mohammad Ghorbani
Abstract
Vegetation cover as the main factor affecting the water erosion plays an important role in preventingsoil loss. To this end, for better understanding the impact of vegetation cover on soil erosion andsediment yield over the major existing geological formations in the summer rangelands of Balade inthe ...
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Vegetation cover as the main factor affecting the water erosion plays an important role in preventingsoil loss. To this end, for better understanding the impact of vegetation cover on soil erosion andsediment yield over the major existing geological formations in the summer rangelands of Balade inthe Mazandaran province, rainfall simulation studies have been carried out using a portable rainfallsimulator. Among many geological formations across the study area, the three major lithological unitsof mica sandstone, clay and shale sandstone with coal seams of “SHEMSHAK”, structures of tuffshale and dark gray to green shale with volcanic rocks of “KARAJ” and limestone of “LAR” havebeen selected as lowly, moderately and highly resisting formations to degradation. For eachcombination of geological formation and vegetation cover (low, moderate, and high density) threesampling plots of 1x1m have been selected and rainfall simulation has been conducted over them. Foreach plot, the surface characteristics including the vegetation cover, runoff and sediment yield and soiltexture were measured. The measured data were statistically analyzed. Results showed that“SHEMSHAK”, “KARAJ” and “LAR” formations were respectively ranked from highest to lowestwith respect to the volume and weight of sediment yield. Also, there was a strong inverse relationshipbetween vegetation cover percentage and volume of runoff and sediment for all investigatedgeological formations specially in poor vegetation situation that indicate interaction effects betweenvegetation cover and type of geological formations.
