In collaboration with Iranian Watershed Management Association

Document Type : Research Paper

Authors

1 Assistant Professor, Water Engineering Department, Faculty of Agriculture, University of Zanjan, Zanjan, Iran

2 Msc of Irrigation and Drainage Expert, Water Engineering Department, Faculty of Agriculture, University of Zanjan, Zanjan, Iran

3 Msc of Irrigation and Drainage, Water Engineering Department, Faculty of Agriculture, University of Zanjan, Zanjan, Iran

Abstract

Introduction
The availability of water for agriculture is of great importance, and despite the water crisis that is becoming more severe every year, both quantitatively and qualitatively, this issue should be seriously considered. Water resources include surface and groundwater, which are qualitatively more at risk, therefore, in order to preserve them, the sources of pollution must be known and appropriate solutions must be provided to prevent or eliminate these pollutions.
 
Materials and methods
In this research, phosphate transfer cycle in Zanjanrood Watershed has been simulated using SWAT model. For calibration and validation, SWAT-CUP software and measured values ​​of average monthly current intensity at Sarcham hydrometric station between (1996-2013) were used and 26 sensitive parameters were selected for sensitivity analysis. There are three options for irrigation method, three options for fertilizer application and two combined options. In order to analyze the uncertainty of the indicators p-factor and r-factor and to analyze the quality of the model results, two indices of coefficient of determination (R2) and nash-sutcliffe coefficient (NS) have been used.
 
Results and discussion
In the monthly runoff calibration stage, at the output of the field, the coefficients of r-factor, p-factor, R2, NS were 0.27, 0.11, 0.83 and 0.53, respectively, and in the validation stage were 0.60, 0.18, 0.73 and 0.53, respectively. The results showed that with increasing the level of pressurized irrigation, the amount of phosphate contamination at the outlet of the basin did not change significantly. Regarding the amount of fertilizer, the 50% reduction in the consumption of phosphate fertilizers has reduced the amount of phosphate entering the Zanjanrud River by 19.2%. On the other hand, a 50% increase in the use of fertilizers has increased the input phosphate by 17.7%.
 
Conclusion
The results showed the proper performance of the SWAT model and its ability in the mentioned simulation. Also, by changing the surface irrigation method to subsurface and increasing the irrigation efficiency, there is no significant change in the average amount of phosphate output from the basin. On the other hand, by reducing the amount of fertilizer and preventing improper fertilization by farmers, pollution of surface and groundwater resources can be greatly prevented.

Keywords

Abbaspour, K.C., Yang, J.,  Maximov, I., Siber, R., Bogner, K., Mieleitner, J., Zobrist, J., Srinivasan, R., 2007. Modeling of hydrology and water quality in the pre-alpine/alpine Thur Watershed using SWAT. J. Hydrol. 333, 413-430.
Abbaspour, K.C.J., 2011. User manual for SWAT-CUP4. SWAT calibration and uncertainty analysis programs. Swiss Federal Institute of Aquatic Science and Technology, Eawag, Duebendorf, Switzerland.
Agriculture Organization of Zanjan Province. 2013. Report on the efficiency of irrigation systems in Zanjan Province. Agriculture Organization of Zanjan Province, 1-174 (in Persian).
Akbari, M., Bahremand, A., Najafi Nejad, A., 2012. Sensitivity analysis of parameters in SWAT model in Chehelchay Watershed in Guilan Province. J. Agric. Sci. Tec. Water Soil Sci. 67(18), 279-287 (in Persian).
Asadi, M., 2005. Non-point water pollution, problems and perspectives. Proceedings of Second National Conference on Watershed Management and Water and Soil Management, Shahid Bahonar University, Kerman, Iran (in Persian)
Arnold, J.G., Srinivasan, R., Muttiah, S., Williams, J.R., 1998. Large area hydrologic modeling and assessment. Part I Model development. J. Am. Water Resour. 34(1), 73-89
Bagherzadeh, A., Pirouz, B., Sabeti Raftar, A., 2009. Effects of urban, industrial and agricultural pollutants on water quality in Goharrood River in Rasht County, Guilan Province. Proceedings of 8th International River Engineering Seminar, Shahid Chamran University, Ahvaz, Iran (in Persian)
Ballantine, D., Walling, D.E., Leeks, G.J., 2009. Mobilization and transport of sediment-associated phosphorus by surface runoff. Wat. Air and Soil Poll. 196, 311-320.
Gassman, P.W., Osei, E., Saleh., A., Rodecap, J., Norvell, S., Williams, J., 2006. Alternative practices for sediment and nutrient loss control on livestock farms in northeast Iowa. Agric. Ecosyst. Environ. 117, 135-144. 
Ghodousi, M., Delavar, M., Morid, S., 2014. The effect of land use on the hydrology of Aji Chai Basin in the Urumieh Lake, Iran. J. Water and Wine Res. 45 (2), 123-133 (in Persian).
Kang, M.S., Park, S.W., Lee, J.J., Yoo, K.H., 2006. Applying SWAT for TMDL programs to a small watershed containing rice paddy field. Agric. Water Manag. 79, 72-92.
Lee, M.S., Park, G.A., Park, M.J., Park, J.Y., Lee, J.W., Kim, S.J., 2010.  Evaluation of non-point source pollution reduction by applying best management practices using a SWAT model and quickbird high resolution satellite imagery. J. Environ. Sci. 22(6), 826-833. 
Lei, W., Yu, U., Xia, T., Long, L., Jin-Song, G., 2012.  Impacts of climate and land-use changes on the migration of non-point source nitrogen and phosphorus during rainfall-runoff in the Jialing River Watershed, China. J. Hydrol. 475, 26-41.
Logan, T.J., 1993. Agricultural best management practices for water pollution control: current issues. Agric. Ecosyst. Environ. 46, 223-231.
Lucy, O., Andrew, W., 2009. Controlling nitrate pollution: an integrated approach. Land Use Policy 26, 799-808.
Markantonatos, P.G., Bacalis, N.C., Angelidis, M.O., 1995. Pollution control in the catchment basin of the river Evrotas, Greese. Water Sci. Technol. 32, 247-255.
Moriasi, D.N., Arnold, J.G., 2007. Model evaluation guideline for systematic quantification of accuracy in watershed simulation. J. T. ASABE 50(3), 885-900.
Mostaghimi, S., Park, S.W., Cooke, R.A., Wang, S.Y., 1997. Assessment of management alternatives on a small agricultural watershed. Elsevier sci. 31(8), 1867-1877. 
Naramngam, S., Tong, S.T.Y., 2013. Environmental and economic implications of various conservative agriculturalpractices in the upper little Miami River Basin. Agric. Water Manag. 119, 65-79. 
Neitsch, S.L., Arnold, J.G., Kiniry, J.R., Williams, J.R., 2005. Soil and water assessment tool theoretical documentation version 2005. Soil and Water Research Laboratory-Agricultural Research Service, Blackland Research Center-Texas Water Resources Institute, Technical Report No.406.
Pasandiadeh Fard, Z., Salman Mahini, A., Mirkarimi, H., 2012. Assessing river water quality improvement by best practices of management (BMP) and modeling techniques. Proceedings of  Second Conference on Environmental Planning and Management, Tehran University, Tehran (in Persian)
Pisinaras, V., Petalas, C., Gikas, G.D., Gemitzi, A., Tsihrintzis, V.A., 2010. Hydrological and water quality modeling in a medium-sized basin using the Soil and Water Assessment Tool (SWAT).  Desalination 250, 274-286. 
Schilling, K.E., Wolter, C.F., 2009. Modeling nitrate-nitrogen load reduction strategies for the Des Moines River, Iowa Using SWAT. J. Environ. Manage. 44(4), 671-682.
Turner, R.E., Rabalais, N.N., 2003. Linking landscape and water quality in the Mississippi River Basin for 200 years. J. Biosci. 53(6), 563-572.
Wu, Y., Chen, J., 2013. Investigating the effects of point source and nonpoint source pollution on the water quality of the East River (Dongjiang) in South China. Ecol. Indic. 32, 294-304.
Zahabion, B., Goodarzi, M., Massah Bouwani, A., 2010. Application of SWAT model in basin runoff estimation in future periods affected by climate change. Clim. Stu. (1), 45-60 (in Persian).