Mehrnoush Ghadimi; Hasan Ahmadi; Ebrahim Moghimi; Mansour Jafarbeyglou
Abstract
To evaluate the hydrogeochemical characteristics of karst water resources of Oshtorankooh, chemistry details of springs has been considered as the most important evacuator of karst resources. This research has been performed to study hydrogeochemical nature of karst springs and their origin with an emphasis ...
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To evaluate the hydrogeochemical characteristics of karst water resources of Oshtorankooh, chemistry details of springs has been considered as the most important evacuator of karst resources. This research has been performed to study hydrogeochemical nature of karst springs and their origin with an emphasis on the type of formation. Accordingly, five samples of the water of permanent springs of this region in the water scarcity time period have been collected and analyzed. To precisely characterize the hydrochemistry of the region, Piper as well as Stiff graphs were employed. The former graph confirmed that the dominant type of the water the region is Calcite-Bi carbonate based. This water possesses a temporal hardness wherein according to the Stiff graph the dominant cautions and anions are bicarbonate and calcium, respectively. The water of the springsPanbekar S1 and Gahar lake S3 are saturated of calcite mineral, and the positive saturation index implies a diffusive flow. The respective flow reflects less development of fractures in the catchment of the springs. The saturation index of dolomite in the springs of Absefid S2, Tamdarbasoo S4 and Mehrghayoonja S5 is negative implying the saturation conditions and reflecting the higher density of surface and sub-surface fractures as well as the type of conduit-diffusion flow along the flow path of these springs. The results of hydrogeochemical analysis also XRF of Karst springs of the field demonstrated that super saturation phenomenon mainly occurs in water scarcity period. Moreover, the chemical nature of the underground waters present in the carbonated stones (rocks) is strongly dependent on the dissolution of calcite also dolomite. The higher water temperature of the Panbekar spring is affected by saturation index of dolomite in Dalan formation. The results of factor analysis also verified that the most important factor could be dissolution of carbonate then magnesium and electrical conductivity. The water of this spring is classified in the group of relatively hard and hard waters.
Aliakbar Nazari Samani; Fatemeh Avazadeh Tavakoli; Hassan Ahmadi; Gholamreza Rahi
Abstract
Gully erosion is one of the most destructive types of channeled water erosion that removes aconsiderable volume of soil as it develops. This type of erosion consists of complex a geomorphicprocess that has been known as an indicator of accelerated soil erosion. In this research theadvancement of 25 headcuts ...
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Gully erosion is one of the most destructive types of channeled water erosion that removes aconsiderable volume of soil as it develops. This type of erosion consists of complex a geomorphicprocess that has been known as an indicator of accelerated soil erosion. In this research theadvancement of 25 headcuts were assessed through digital interpretation of multi-temporal aerialphotos, field observations and GIS data analysis over the two periods of 1967-1995 and 1995-2008.Moreover, the stepwise regression analysis procedure was applied to extract the effective factors ongully head advancement (such as topography, physico-chemical soil attributes and morphology ofgully). The results indicated that the mean of gully head advancement over the periods of 1967-1995,1995-2008 and the mean of two periods were measured 1.36, 1.23 and 1.3 m/y, respectively. Further,regression analysis revealed that headcut's contribution area, distance of gully-head to ridge, height ofgully head cut and SAR are the main factors on gully head advancement. Therefore, distance to ridge,headcut high and presence of plunge pool could use as suitable criteria to distinguish the active gulliesin order to prioritizing the conservation activities.
Sadat Feiznia; Soheila Youneszadeh Jalili; Hasan Ahmadi
Abstract
Due to difficulties in the application of traditional methods for identifying sediment sources, fingerprinting techniques, based on physical, chemical and organic properties of sediment and source materials, are increasingly being used as a valuable and effective alternative approach to obtain such information. ...
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Due to difficulties in the application of traditional methods for identifying sediment sources, fingerprinting techniques, based on physical, chemical and organic properties of sediment and source materials, are increasingly being used as a valuable and effective alternative approach to obtain such information. The first step in this method is using an appropriate combination of diagnostic properties that is able to differentiate sediment sources. In this study a combination of properties was used in different subbasins of Khur-Sefidarak Basin, located in Savojbolagh Township, Alborz Province and the share of each lithological unit on production of suspened load was estimated. By preparing lithological map, lithological units are considered as sediment sources and sediment behind the small dams are considered as deposittional areas. Aboat 43 samples were taken from lithological units and trap sediments of small dams in outlet of different sub basins. Then particle sizes finer than 62.5 µ were seprated and concentration of nine geochemical elements in the samples were obtained. After being certain about absence of outliers data and after using analysis of variance and Kolmogorov-Smirnov Tests, discriminant analysis is used for finding the final proper combination. Among different elements, Ca is the most important element for differentiating geological units in different subbasins of Khor-Sefidarak Basin. Finally, relative importance of each geological unit in producing suspended load was calculated. Results have shown that Zagun and Shemshak Formations have the highest share in sediment production of the area.
Tayyebeh Mresbahzadeh; Hasan Ahmadi; GHolamreza Zehtabian; Fereydun Sarmadian; Firoozeh Moghiminejad
Abstract
Desertification is specific phenomenon of arid, semi-arid, dry sub humid regions. This phenomenon has a high rate in developing countries such as Iran. The main objective of this research was calibration of IMDPA model in Abuzeidabad (Kashan) region with emphasis on land criteria. IMDPA model, introduced ...
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Desertification is specific phenomenon of arid, semi-arid, dry sub humid regions. This phenomenon has a high rate in developing countries such as Iran. The main objective of this research was calibration of IMDPA model in Abuzeidabad (Kashan) region with emphasis on land criteria. IMDPA model, introduced by Iranian researchers to assess desertification intensity in Iran. Before application, the criteria and indices applied in model were re-defined For this study. Regarding to region conditions three criteria were defined as key criteria for desertification which were: Geology-geomorphology, soil and wind erosion criteria. Then each criterion was assessed based on selected criteria, which resulted in qualitative mapping of each criterion based on selected criteria. Finally, by mean of all the indices and criteria desertification mapping was provided and these results obtained. Regarding the studied criteria, Geology– Geomorphology benchmark has the highest effect on desertification. Among the total studying are (16161 hectars), the medium class is about (4792 hectars), and the high class is about (11369 hectars). Among indicators, slop index with 3.9 and lithology sensitivity to erosion and wind erosion with the value of 3.5 and 3.4 are the main indexes of increase in desertification intensity in the study area. According to map of desertification statue 70.3% of study area have a high intensity and 29.7% have a medium intensity.