Sensitivity Analysis of MPSIAC Model

Document Type : Research and Full Length Article

Authors

1 Islamic Azad University, Science and Research Branch-Tehran

2 Faculty member, Research Institute for Water Scarcity and Drought in Agriculture and Natural Resources (RIWSD), Tehran

3 Head of Soil Science Department, Islamic Azad University, Science and Research Branch-Tehran

Abstract

MPSIAC is currently known as an appropriate method to measure sediment of
Watershed basins of the country while there has not been any sensitivity analysis so far for
this method. In this study, required data for MPSIAC model were gathered from six basins;
Amame-Kamarkhani, Kand-Golandok, Tang Kenesht (from two different references), Nojian
(from three different references), Pegahe sorkh katvand (from one reference) and Ivanaki
(authors’ research). Eleven sensitivity analyses were conducted and the amount of sediment
was calculated using the sum of nine factors. Each input parameter was increased or
decreased by 20% using a computer program in Visual Basic in Excel. Then sensitivity of the
model for the parameters was analyzed. The less sediment has the basin, the less sensitivity
has the input parameters in the model. MPSIAC model has twenty input variables that
resulted in nine main factors. Erosion parameter (R) was calculated by adding nine main
factors and the quantity of sediment was calculated by an exponential function. By evaluation
of nine main factors, it was concluded that land use and Gully development were the most
sensitive factors. As a result, based on the area and sensitivity of main factors, more
investments must be done on the most sensitive factor to reduce soil erosion. In the
assessment of nine main factors occurred errors are reduced due to adding operation.
Regarding all items, each factor that has more input quantity has the highest sensitivity. As a
result, if score of each factor grows more than six, more attention must be paid to score
assignation. If occurred errors in assessment of nine factors did not neutralize each other and
have additive or decreasing on the R, by addition of 20% to R, it showed that this factor was
the most sensitive factor to run the model. If R is equal to 60 and 20% related to the error
occurred in calculation of it, 54% error occurs in estimating the amount of sediment and
sensitivity reaches to 2.7. This evaluation indicated that MPSIAC model for evaluation of
basins with the amount of sediment more than 2.2 ton/hectare must be used more preciously
because the model is so sensitive in this status and possible error may get over 50%.

Keywords


Asareh. A., Sensitivity analysis LEACHN
model than the input parameter in
stimulating soil moisture. 2008. Second
natural congress of managing irrigation
and drainage network. Ahvaz University.
(In Persian).
Bayat. R., Evaluation of efficiency of
sedimentation maps by using MPSIAC
and EPM in Taleghan by GIS. 2000.
Thesis of master degree. Department of
Soil Science. Faculty of agriculture.
University of Tehran. (In Persian).
Ghodrati. M., Evaluation of sedimentation
in Watershed without hydrometer station
by using PSIAC in Semnan river basin.
1996. Thesis of master degree.
Department of Environment. University
of Tehran. (In Persian).
Haregeweyn, N., J. Poesen, J. Nyssen, G.
Verstraeten, J. D. Vente, G. Govers, S.
Deckers and J. Moeyersons. 2005.
Specific sediment yield in TigrayNorthern Ethiopia: Assessment and semiquantitative modeling. Geomorphology,
69: 315-331.
Hashemi. A. A. 2002. Review and
comparing between two models of
estimating sediment and erosion in
central of Alborz (Semnan Province).
Collection of articles national congress
land managing-soil erosion and
0.2000
0.1600
0.1200
0.0800
0.0400
0.0000
0.3000
0.2500
0.2000
0.1500
0.1000
0.0500
0.0000
This is trial version
www.adultpdf.com
J. of Range. Sci., 2011, Vol. 1, No. 4 Sensitivity Analysis …/302
sustainable development. pp: 594-603,
(In Persian).
Jalalian. A. 1990. Quality and quantity
research of soil erosion in north
Watershed basin river Karoon. Jour. Iran
Natural Resources, 43: 27-45 (In
Persian).
Johnson, C. W., and K. A. Gebhardt, 1982.
Predicting sediment yield from sagebrush
rangelands. Proceeding of workshop on
estimating erosion and sediment yield on
rangelands, Tucson, Arizona, March
1981. US Department of Agriculture,
Agricultural Reviews and Manuals,
Western Series, 26: 145-156.
Lane, J.W., and Ferrira, V.A. 1982.
Sensitivity analysis. In CREAM, A field
scale model for chemical, Runoff and
EROSIN from Agricultural Management
system, (ed.) W.G. Knisel,.Vol. A. Model
Documentation. USDA conservation Res.
Report No. 26. 113-158. Washington,
D.C.
Parehkar, M. 1999. Ground Water
recharges process under Arid and Semiarid Condition. PhD Thesis. Cranfield
University, Bedfordshire UK.
Parsaee. L. 2005. Evaluation of efficiency
of experimental models (EPM, MPSIAC)
in predicting sediment and erosion in
Watersheds of Gholestan province, Iran.
Central investigation of environmental
source. Institute soil conservation and
Watershed management. (In Persian).
Rafahi. H. G. H. (1997). Water erosion and
conservation. Publications of Tehran
university pp: 544. Tehran, Iran (In
Persian).
Rastgoo, S. B. Ghahraman, H. Sanaiinejad,
k. Davari and S. R. Khodashenas. 2006.
Estimation of erosion and sediment in
Tang Kenesht Watershed using MPSIAC
and EPM models and GIS, Jour. Agri
and Natural Resources Science and
Technique, 1: 91-104. (In Persian).
Reynard, K.G., and J.J. Stone. 1982.
Sediment yield from small semiarid
range land watersheds. USDA-SEAARM, Western Series-No: 26: 129-144.
Shade, P., 1986. Sediment yield of three
drainage basins in Guam. In proceeding
of the fourth federal interagency
sedimentation conference, pp: 252-260.
(In Persian).
Shah Karami. A. 1995. Evaluation of
sedimentation by using PSIAC,
MPSIAC, EPM in Nojian Watershed.
Collect of articles national congress land
managing. Arak. pp: 562-572. (In
Persian).
Sheikh Hasani, H. 1995. Evaluation
potential sedimentation in erosion units
of Watershed basin Taleghan. Thesis for
MSc degree. Department of Human
Science. University of Tarbiat Modares,
Iran.
Sokoti Oskoie. R., A. Boroshke, J.
Ghodosi, M. Arabkhadri. 2001.
Evaluation of efficiency of MPSIAC
model in Evaluation of sedimentation
five basins of west Azerbaijan Province.
Research and Construction, 14: 35-37 (In
Persian)