Showing 4 results for Nikkami
Kh. Jalili, S. H. R. Sadeghi, D. Nikkami,
Volume 10, Issue 4 (winter 2007)
Abstract
Improper management of watershed land utilization has many ill effects on the available resources. Land use optimization is one of the proper strategies to achieve sustainable development and to reduce resource dissipation. Focusing on Brimvand watershed in Kermanshah province which comprises an area of 9572 ha, the present study was conducted to find out the most suitable land allocation to different land uses viz. garden, irrigated farming, dry farming and rangeland to achieve soil erosion minimization and benefit maximization. The soil erosion, net benefit and standard land capability maps were supposed as the inputs of the objective functions and to defined constraints. The multi-objective linear problem was then solved using simplex method with the help of ADBASE software package and ultimately the optimal solution was gained. Additionally, the results of the study revealed that the amount of soil erosion could reduce by 7.78% whereas the benefit increases at the rate of 118.62%, in case of implementation of optimal solution. The above mentioned optimization led to dry farming decrease and garden increase over that area. The results of sensitivity analysis also showed that objective functions were strongly susceptible to the variation of maximum constraint of irrigated farming and garden areas.
A. Mohammadi Torkashvand, D. Nikkami,
Volume 11, Issue 42 (winter 2008)
Abstract
Erosion features map is one of the basic maps in erosion and sediment studies considered important in watershed management programs. For preparing soil erosion features map (1:250000 scale), a study was conducted in Jajroud sub-basin of Tehran, Iran. Working unit maps were prepared from integrating: A) plant cover, geology and slope B) land-use, geology and slope C) land-use, rocks sensitivity to erosion and slope and D) land-use, rocks sensitivity to erosion and land units. Working unit maps obtained from integrating layers were compared with three other maps consisting of working units maps according to E) land units F) rocks sensitivity to erosion units and G) image photomorphic units. Erosion features intensities in 314 control points were controlled and erosion features ground truth map was prepared by Thiessen method and using satellite imagery. Erosion features map was crossed with different working unit maps. Results showed that D map was better than A, B and C maps with regard to economic considerations. Accuracy was 53.0 and 42.9% for methods of land unit and rock sensitivity which resulted in the maps not suitable for differentiating soil erosion features. Root Mean Squared Error of working units showed that the error of land unit and rock sensitivity methods was more than image interpretation and integrated layers methods. The highest coefficient of variation was related to land unit and rock sensitivity to erosion methods and was the least for image interpretation and integrated layers methods. The greatest precision, therefore, was related to image interpretation and integrated layers methods. In general, working unit map of image interpretation was the best method for preparing soil erosion features map.
N. Khorsandi, M. H. Mahdian, E. Pazira, D. Nikkami,
Volume 15, Issue 56 (sumer 2011)
Abstract
Rainfall erosivity force as on important factor in soil erosion and sediment yield has been introduced in different indexes. The objective of this study was to determine suitable rainfall erosivity indices for two climates of semi-arid in Maravetape and very humid in Sangdeh, both in Khazar watershed, by correlation between rainfall erosivity indices and sediment outflow from erosion plots. For this purpose, the rainfall intensities in different time steps and the amount of rainfalls of 12 events in Maravetape and 11 events in Sangdeh have been used. Twonty five rainfall erosivity indexes were calculated based on rainfall intensity. The amount of soil loss measured after each rainfall event in 1.8×22.1 m2 erosion plots. The results of the study revealed that in very humid climate of Sangdeh and in semi-arid climate of Maravetape had high correlation of 0.803 and 0.727 (at the level of 99 percent) with sediment yield and they were applied indices in these climates of Khazar watershed. In general, the groups of 10 and 30 minutes are better than other erosivity indices in the study areas.
H. Khaledian, D. Nikkami,
Volume 21, Issue 1 (Spring 2017)
Abstract
Appropriate utilization of agricultural land and natural resources, decreased erosion and increased production occurs in watersheds. On the other hand, land use pattern due to increasing human activities on the ground to meet different needs, is changing. Optimization of land use is one of the management methods to achieve stability and reduce soil erosion. In this study, by using linear programming (simplex) and Geographic Information System(GIS), was investigated the land use optimization in three scenario option to: current condition, management condition, and standard condition.Erosion potential by using MPSIAC Model in irrigated land 1.65, dry lands 3.31, pasture 3.64, gardens 1.49 and 3.85 tons per hectare per year was estimated for Chehel-Gazi basin. The results of the sensitivity analysis for tree scenario showed that in the event optimize land use, erosion potential in the current Condition 0.85 percent increased, But in the land management Condition 16.92 percent and in a standard Condition 32 percent decreased. The results of sensitivity analysis showed that changes in the area of pasture all three options have the greatest impact in changing erosion potential of basin.
