Papers by Abdulvahed Khaledi Darvishan
The Journal "Agriculture and Forestry", 2019
Topsoil is the richest part in terms of the amount of organic matter and nutrients. Therefore, it... more Topsoil is the richest part in terms of the amount of organic matter and nutrients. Therefore, its lost is more harmful compared to the subsoil. During the erosion process, soil nutrients are either lost as dissolved or absorbed to the soil particles. The present study was aimed to investigate the effects of rainfall intensity and slope gradient on infiltration, runoff, soil and nutrients (N, P, K) loss in rainfed lands of Pishkamar region, NE of Iran. To achieve the study purposes, four rainfall intensities of 33, 64, 80 and 110 mm h -1 were simulated using Kamphorst rainfall simulator in three slope gradients of 6, 12 and 25%. Two slope aspects of north and south were also considered for the slope gradient of 25%. The results showed that the effects of rainfall intensity and slope gradient on infiltration and runoff were significant, while the effect of slope aspect (north and south) was not. Taking into account the linear trend, the plot hydrological response threshold of sediment concentration was about 50 mm h -1 of rainfall intensity and 9% of slope. In the case of total soil loss, however, higher thresholds were obtained for rainfall intensities (about 72 mm h -1 ) and slope gradients (about 18%). The effect of rainfall intensity and slope gradient on soil loss were significant individually, but no interaction was observed among study factors. The results of nutrient losses showed considerable loss for Potassium in the runoff and Phosphorus and Potassium in the sediment.
The Journal "Agriculture and Forestry", 2019
The complexity of hydrological processes, spatial and temporal variation of all effective factors... more The complexity of hydrological processes, spatial and temporal variation of all effective factors and lack of essential measured filed data convinced researchers to use empirical models in various scales. The IntErO model was used to predict maximum outflow (Qmax), soil erosion intensity (W year) and sediment yield (G year) in one of the internal sub-watersheds of Shirindarreh watershed, northeast of Iran. The results showed that the peak flow was 13.51 m 3 s -1 for a return period of 100 years. As an internal area, the peak flow of all upstream sub-watersheds should be also considered to be added to the predicted peak flow. The value of Z coefficient of 0.696 indicated that the river basin belongs to III destruction category and the strength of the erosion process was medium, and according to the erosion type, it was intrusive erosion. The predicted gross soil erosion in the study sub-watershed was 8.06 ton ha -1 year -1 . The coefficient of the deposit retention (Ru) or sediment delivery ratio (SDR) was 0.124 and therefore, the sediment yield was 1.00 ton ha -1 year -1 . According to Gavrilovic, the study sub-watershed is a region of very weak erosion.
Journal of Water and Soil Science, 2021
International Soil and Water Conservation Research, 2018
Monitoring the sediment transport behavior induced by different interventions, particularly sand ... more Monitoring the sediment transport behavior induced by different interventions, particularly sand mining from rivers, is needed to adaptively manage the watersheds. The particle size distribution of the suspended sediment in up and downstream of rivers is one of the main indicators to know about fate of sediments, which may be varied in different conditions. We investigated the effect of some types of sand and gravel (i.e., manual and low, semi-heavy, and heavy machinery) mining on particle size distribution of suspended sediment in the Vaz-e-Owlya, Vaz-e-Sofla and Alesh-Roud riverine mines located in Mazandaran Province, northern Iran. The study was conducted on a monthly basis from February, 2012 to January, 2013. Laser granulometry was used to analyze the particle size distribution of suspended sediment samples taken from up and downstream sections of the study mines. The results revealed that the level and intensity of mining activity affected particle size distribution of suspended sediments. Further statistical assessments in up and downstream sections of the mines proved that sorting, D50, mean, D90, kurtosis, skewness and D10 of the suspended sediment were not significantly influenced by mining activities at levels of 0.09, 0.11, 0.12, 0.15 to 0.69, 0.15-0.69, 0.77, 0.87, 0.97, respectively. While it was not statistically significant, we found that the type of mine and the level of the exploitation changed the particle size distribution of the suspended sediment.
The Journal "Agriculture and Forestry", 2018
Splash erosion is caused by the impact of raindrops on the soil surface and leads to the detachme... more Splash erosion is caused by the impact of raindrops on the soil surface and leads to the detachment of the soil particles. The most effective measures for reducing soil splash are the use of conditioners to improve soil aggregates stability and/or to deploy physical barriers to minimize raindrop impacts. The present study has been conducted to examine the efficiency of sawdust to reduce splash erosion rate in an 15% gradient slope with sandy-clay-loam soil in the laboratory condition, To achieve the study purposes, the soil were covered by sawdust with the surfaces percentages of 30, 50, 70 and 90% in splash cups were placed on the soil in three replicates for each control and treated conditions. A portable rainfall simulator was used to simulate rainfall with the intensity and duration of 40 mm h-1 and 15 min, respectively. The results of splash showed that the sawdust reduced both total and net splash.
AGROFOR, 2018
Application of empirical models is inevitable because of the complexity of process,features, spat... more Application of empirical models is inevitable because of the complexity of process,features, spatial and temporal variation of soil erosion and non-existence or lack ofassociated data. In the present study, maximum outflow and soil erosion intensitywere predicted for Khamsan representative watershed in West of Iran, using IntEromodel. The results of production of erosion material in the river basin (W year),coefficient of the deposit retention (Ru) and real soil losses (G year) were thencompared with the measured soil erosion, SDR and sediment yield data inKhamsan watershed. The intensity of the erosion process were medium in studiedwatershed. The predicted data were compared with the measured sediment yield ofstudied watershed and verified the acceptable results of the IntEro model inKhamsan representative watershed. The results showed that the peak flow is 27.50m3s-1 for a return period of 100 years. The value of Z coefficient of 0.876 indicatesthat the river basin belongs to the ...
AGROFOR, 2016
Nowadays watershed and rangeland management projects play the important rolein water resources an... more Nowadays watershed and rangeland management projects play the important rolein water resources and soil management worldwide. Although watershed andrangeland management projects have the considerable importance as approaches torural areas development and natural resources management, more studies havebeen focused on their effects on sediment and their effects on soil erosion haverarely been considered. The present study was conducted in two treated and controlsub-watersheds with exclosure treatment and under grazing respectively, inKhamsan representative watershed with an area of 4337.27 ha in south ofKurdistan Province, Iran. Three plots were installed in each western, northern andeastern slopes for the runoff volume and coefficient, sediment concentration andsoil loss measurement. The exclosure treatment was operated for installed plots intreated sub-watershed from 2007. Then, all the data of runoff volume andcoefficient, sediment concentration and soil loss from USLE standard plo...
International Agrophysics, 2015
Although the possibility of measuring and analysing all parts of the rainfall, infiltration, runo... more Although the possibility of measuring and analysing all parts of the rainfall, infiltration, runoff, and erosion process as a natural hydrologic cycle in field conditions is still one of the more unattainable goals in the hydrological sciences, it can be accomplished in laboratory conditions as a way to understand the whole process. The initial moisture content is one of the most effective factors on soil infiltration, runoff, and erosion responses. The present research was conducted on a 2 m2 laboratory plot at a slope of 9% on a typical sandy-loam soil. The effects of the initial soil moisture content on the infiltration, runoff, and erosion processes were studied at four levels of initial soil moisture content (12, 25, 33, and 40 volumetric percentage) and two rainfall intensities (60 and 120 mm h-1). The results showed a significant (p ≤ 0.05) correlation between rainfall intensity and downstream splash, with r = 0.87. The results reflected the theory of hydrological responses, ...
Journal of Water and Land Development, 2014
Mulches have extraordinary potential in reducing surface runoff, increasing infiltration of water... more Mulches have extraordinary potential in reducing surface runoff, increasing infiltration of water into the soil and decreasing soil erosion. The straw mulches as a biological material, has the ability to be a significant physical barrier against the impact of raindrops and reduce the detachment of soil aggregates. The present study is an attempt to determine the efficiency of straw mulch as conservation treatment in changes in the splash erosion, time-to-runoff, runoff coefficient, infiltration coefficient, time-to-drainage, drainage coefficient, sediment concentration and soil loss. The laboratory experiments have been conducted for sandy-loam soil taken from deforested area, about 15 km of Warsaw west, Poland under lab conditions with simulated rainfall intensities of 60 and 120 mmh–1, in 4 soil moistures of 12, 25, 33 and 40% and the slope of 9%. Compared with bare treatments, results of straw mulch application showed the significant conservation effects on splash erosion, runoff...
Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation, 2010
Efficacy of Time-Area Method in simulating temporal variation of sediment yield in Chehelgazi wat... more Efficacy of Time-Area Method in simulating temporal variation of sediment yield in Chehelgazi watershed, Iran The proper prediction of temporal and spatial variation of sediment yield from the watershed is a need for sediment control, river engineering and soil and water conservation studies. The present study was therefore planned to simulate the sediment graphs for Chehelgazi watershed in Gheshlagh dam upstream in Kurdistan Province, Iran, by using Time-Area Method. Towards this attempt, the study watershed was divided into 7 time-area segments based on the time of concentration. The soil erosion in each segment was estimated using the USLE and then routed to the main outlet using sediment delivery ratio as a function of land slope in two adjacent time-areas. The temporal variation of sediment was ultimately predicted with the help of lag time of sediment arrival to the outlet and the concept of superposition for 11 storm events, which occurred during winter 2006 and spring 2007. ...
Soil erosion and sediment yield from watersheds are key limitations for achieving sustainable lan... more Soil erosion and sediment yield from watersheds are key limitations for achieving sustainable land use and maintaining water quality in streams, lakes and other water bodies. Studying soil erosion process and sediment yield and evaluation of dominant factors on erosion is therefore considered as one of the fundamental tasks in proper management of watershed resources. Insufficient information regarding the sediment yield during storms is also one of the old issues which mainly causes failure of soil and water conservation projects. In this research, development and analyzing rating loops of Chehelgazi watershed of Gheshlagh dam was investigated. To achieve the study purposes, the rating loops of 11 storm events from winter 2006 to spring 2007 were investigated. The sediment samples were taken immediately after measuring flow velocity with half an hour interval through intergration method for 11 storm events. The sediment yield was then determined for each study storm through laborat...
Litnology and sedimentology factors affect on downstream changes in bed load shape and can be use... more Litnology and sedimentology factors affect on downstream changes in bed load shape and can be useful to detect watershed hydrological processes as they are very important to design hydraulic structures and reservoir management. This research was conducted in Qalesar River in Mazandaran Province with main river length of 24 Kilometers. After recognition of the study area, 11 sections were selected toward downstream for bed load sampling. Laboratory analysis were done using gravel meter and sieving method to measure and calculate some bed load shape characteristics. Also physical properties of each sub-watershed were extracted using Arc/GIS 9.2 software. Finally, in order to determine most effective physical characteristics on bed load shape, data were analyzed using SPSS 16. Results of statistical analysis indicate the best model between D50 and length of 1 order channel in bivariate regression equations and between D50 and distance from upstream in multi-variate regression equations.
Solid Earth Discussions, 2015
Although various organic and inorganic mulches are used for soil conservation purposes, the compa... more Although various organic and inorganic mulches are used for soil conservation purposes, the comparative effectiveness of them on soil characteristics has not been comprehensively considered from different aspects. The present study is therefore an attempt to determine the efficiency of straw mulch, manure and TA-200 polyacrylamide with respective rates of 500, 300 and 50 g m −2 , respectively, in changing sediment concentration and soil loss. The experiments were conducted for sandy-loam soil (collected from the top 0-20 cm-layer) taken from a summer rangeland, the Alborz Mountains, Northern Iran under laboratory conditions with simulated rainfall intensities of 30, 50, 70 and 90 mm h −1 and the slope of 30 %. The results showed that the straw mulch decreased soil concentration at rate of 45.60 % compared to the control plots, and performed better than manure (8.98 % reduction) and PAM (4.74 % reduction). The results showed that the maximum reduction in sediment concentration and soil loss for all soil amendments occurred in the rainfall intensity of 90 mm h
Hydrological Sciences Journal, 2013
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Papers by Abdulvahed Khaledi Darvishan