Nadergholi Ebrahimi; Reza Sokouti Oskoee
Abstract
Mountainous rivers have characterized by steep slope, roughness due to bedrock and coarse aggregation, bed and marginal vegetation as well as severe and rapid spatial displacement of the surface substrate morphology. The protection role of vegetation in the river bank is known as an economic and environmental ...
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Mountainous rivers have characterized by steep slope, roughness due to bedrock and coarse aggregation, bed and marginal vegetation as well as severe and rapid spatial displacement of the surface substrate morphology. The protection role of vegetation in the river bank is known as an economic and environmental option that decreases hydraulic conductivity power of the river through the rising of roughness coefficient and rising water level. This study aimed to estimate the flow resistance and roughness coefficient of the river that is affected by the physical and biophysical factors of the Shahr-chay River bed in West Azerbaijan in three selected river reach. Results showed that none of the proposed equations for estimation of roughness coefficient depend on energy slope, but in general, without affecting flow, roughness coefficient in mountain streams depends only on the degree of submergence. Marginal trees can affect Froude number by increasing margin pressure and friction forces, also, enhancing the hydraulic depth, less than critical depth. It was also found the equation for estimating roughness coefficient both with and without marginal trees, have different coefficients and can provides roughness coefficient prediction possibility for mountainous rivers. Comparing the obtained relations both with and without its fringe of trees showed that fringe trees can increase the flow depth and roughness coefficient. Coefficient of determination of all mathematical relations was above 0.99 and calculated relative error was 0.001- 0.008 that demonstrates the suitability of the model to estimate the roughness coefficient.
Reza Sokouti; Mohammadhossein Mahdian
Abstract
Floods water contain sediments that affect the fertility of coarse grain alluvial fan and flood plains after deposition, through increasing their nutrients. In this study, the effects of flood spreading were investigated on the recovery of soil nutrients at the Poldasht flood spreading station of west ...
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Floods water contain sediments that affect the fertility of coarse grain alluvial fan and flood plains after deposition, through increasing their nutrients. In this study, the effects of flood spreading were investigated on the recovery of soil nutrients at the Poldasht flood spreading station of west Azerbaijan during 10 years., The first three bands that have been flooded, were selected at the flood spreading channels. In each strip, six soil samples of of 0-20 cm depths, were taken and total nitrogen, phosphorus, potassium, and soil organic carbon were measured. For statistical analysis, t-test non-parametric tests were used where the data had normall distribution or not, respectively; . According to the results, the amount of soil organic carbon and total nitrogen increased from 0.23 to 0.33 and 0.027 to 0.039 percent, respectively during the implementation years. Exchangeable phosphorus and potassium were significantly increased from 2.69 to 5.32 and 145.93 to 206.52 parts per million, respectively. On the other hand, there was a significant difference for some factors of the spreading bands at 5% probability. Amounts of phosphorus, soil organic carbon and nitrogen in the upper strips were significantly more than lower bands. However, there was no significant change on the amount of potassium. The results showed that the flood spreading increased soil nutrients which reduce the fertilizers application.
Reza Sokouti; Hamidreza Peyrowan; Davood Nikkami; Mohammadhossein Mahdian
Abstract
Considering to high distribution of the marly lands in west Azarbaijan province and high sediment yield of such lands, in this research, the relation among the form and the rate of erosion on marls with their erodibility properties were studied. So marly regions of province with the special properties ...
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Considering to high distribution of the marly lands in west Azarbaijan province and high sediment yield of such lands, in this research, the relation among the form and the rate of erosion on marls with their erodibility properties were studied. So marly regions of province with the special properties were recognized and soils were sampled. Soil erodibility indices were determined and analyzed by statistical methods considering the form and the rate of erosion. Also portable rain simulator were used to study of the runoff and sediment yield potential of such soils. Finally the factors affected the soil erodibility were determined by variance analysis. Results showed erosion rate could be classified as moderate. Gully erosion had highest number in Gara-agaj and Gara-tape areas whereas rill erosion had high number in all area of marlly lands. Surface runoff volume ranged between 255 to 577 cm3 in Shabanlu and surface runoff coefficient 0.23 to 0.53 in Gara-tapeh. Maximum yielded turbidity was 180 gr/lit in Gara-Agaj area. Clay ratio was the effective factor to gully form and Surface runoff volume also was the factor to form surface and rill erosion.
Reza Sokouti Oskooei; Mohammad Hossein Mahdian; Shahla Mahmoodi; Mohammad Hasan Masihabadi
Volume 2, Issue 3 , October 2010, , Pages 161-169
Abstract
Planning and suitable management is necessary for optimal use of soil and for this; spatial variability of soil characteristics is important which may be edcarried out through geostatistical methods of parametric and non-parametric predictors such as TPSS, WMA, Kriging and Co-kriging. This research work ...
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Planning and suitable management is necessary for optimal use of soil and for this; spatial variability of soil characteristics is important which may be edcarried out through geostatistical methods of parametric and non-parametric predictors such as TPSS, WMA, Kriging and Co-kriging. This research work was done in Southern part of Uromieh plain with 36690 ha surface area in order to study the spatial variability of soil lime, sand and saturation moisture percentage. Distance between soil profiles ranged 1300 to 4700 meters. For estimation and prediction of them in non-sampled points, the Kriging, Co- kriging and Weighted Moving Average were used in Geographic Information System environment. For selecting suitable interpolation method, Cross validation and MAE and MBE parameters were used. Selected method was also used for estimating and mapping of the selected soil characteristics. The Sturges rule was used for defining map classification. Results showed that the Kriging method has the highest accuracy with correlation coefficient of 0.83 and error of 3.98 percent for prediction of soil characteristics in non-sampled points.
