Suma Mohamadpur; Hamed Rouhani; Hojat Ghorbani Vaghei; Seyed Morteza Seyedian; Abulhasan Fath Abadi
Abstract
In many semi-arid regions of Iran, soil erosion has turned into a serious environmental problem affecting land productivity, nutrient loss, water quality, and fresh water ecosystems. Rates of soil loss differ according to erosion type and land degradation processes. Rill erosion is commonly observed ...
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In many semi-arid regions of Iran, soil erosion has turned into a serious environmental problem affecting land productivity, nutrient loss, water quality, and fresh water ecosystems. Rates of soil loss differ according to erosion type and land degradation processes. Rill erosion is commonly observed when rainstorms occur on steep slopes and sediment transport in rill flows exhibits the characteristics of non-equilibrium transport. In this paper, sediment concentration of rill flow is estimated by adaptive neuro-fuzzy inference system (ANFIS). A series of mathematical equations and parameters affecting rill hydrodynamics and soil detachment were used for well-defined rill sediment concentration. A series of filed experiments were performed to evaluate the model. The stepwise method was used to select the most important and effective input variables from measured input parameters of soil properties, topographic and vegetation attributes affecting sediment concentration of rill flow. Based on the stepwise procedure, the most significant parameters in the model predications were steep slope, vegetation percentage, clay percentage, and shear stress parameters. The values of sediment concentration simulated by the model were in agreement with observed values with Coefficient of Correlation (R2), Root Mean Square Error (RMSE) and Mean Bias Error (MBE) of 0.697, 30.5 and 1.0, respectively. The results of the investigation shows that the data-driven ANFIS modeling approach can be a powerful alternative technique for correctly estimating rill sediment concentration.
Farshad Soleimani; Naser Brumand; ali azareh
Abstract
In recent decades, increasing population growth and development of agriculture have increased groundwater consumption and decreased the quality of groundwater resources of most parts of the country. Given the importance of this issue, present study investigates the spatial and temporal changes in parameters ...
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In recent decades, increasing population growth and development of agriculture have increased groundwater consumption and decreased the quality of groundwater resources of most parts of the country. Given the importance of this issue, present study investigates the spatial and temporal changes in parameters of calcium, magnesium, pH, chloride, sodium sulfate and water in Jiroft plain. The data was obtained from 40 wells in the region of Kerman province over which in 2002-2012 water harvesting and qualitative analysis had been done. In this regard, after normalizing the data, the accuracy of different geo-statistical methods including the Kriging and inverse distance weighted were evaluated and then the map of the spatial zoning was prepared in the software quality parameters ArcGIS9.3 using the best method of interpolation. The results showed that the amount of pH, Sodium, Chlorine, and Sulfate increased but the amount of calcium and magnesium declined. But in general, in 2012the quality of groundwater resources of Jiroft plain decreased compared to 2002 and the trend of changes showed water quality reduces toward the South and West.
Abazar Esmali; Hasan Ahmadi; Mohammad Tahmoures
Abstract
The aim of this research is to describe the development of a methodology based on present knowledge and available data for evaluation of water erosion behavior and risk as well as modeling and estimation of soil erosion, which is compatible for other similar areas of Iran. Accordingly, the conducted ...
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The aim of this research is to describe the development of a methodology based on present knowledge and available data for evaluation of water erosion behavior and risk as well as modeling and estimation of soil erosion, which is compatible for other similar areas of Iran. Accordingly, the conducted research was based on four major types of water erosions including: sheet, rill, channel and riverbank which have considerable role on sediment yields of Baleghli Chay Watershed, Ardebil Province, were separately and spatially studied. In order to determine the inter-effects of effective factors, the study was conducted using stepwise multivariate statistical tests. For each erosion type, an individual model was then presented. In the next step, after determining of relations between sediment yield and environmental factors (fixed & variable) through statistical analyses and selecting of effective factors on erosion and sediment yields, was created an empirical structure for modeling erosion and sediment yields based on MPSIAC erosion model. In formulation of the new model, were used of eight effective factors on erosion in the area. These factors are susceptibility of geological formation, soil erodibility, rainfall erosivity, runoff erosivity, topography, hydrographic drainage, Normalized Difference of Vegetation Index (NDVI) and field conditions of erosion features. In the presented model, with summation of the scores of mentioned eight factors, obtains the M value, which can estimate the amount of erosion and sediment yields of the area, using exponential formula between sediment yield and M values. In addition, in order to obtain the confidence of presented model, it was used in "Nir" catchment for evaluation the precision. The results showed 11 percent difference. With accepting of this error value, the water erosion hazard map of the area was provided and presented using new model.
