Document Type : Research Paper
Authors
1 Professor, Soil Conservation and Watershed Management Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran
2 Associate Professor, Soil Conservation and Watershed Management Research Institute, Agricultural Research,; Education and Extension Organization (AREEO), Tehran, Iran
Abstract
Soil, as one of the components of any ecosystem and an important source of food production, has a very serious role in the continuation of human life. Therefore, the need to support and protect the soil and prevent its erosion is essential. Regarding the amount of soil erosion and sediment yield in the country, different figures have been mentioned and in some studies, the difference is with several times. These figures vary from less than one to more than five billion tons per year. Therefore, calculating and plotting erosion and sedimet yield maps provides important information that is used in the design of dams, reservoirs, canals, soil protection operations, onsite and offsite erosion damage assessment, and land use planning and land capability assessment projects. Soil erosion map is one of the basic, scientific and applied maps in various executive, research and educational sectors. Due to the need of determining the amount of soil erosion and sediment yield for the entire country and determining the executive priorities in areas with high soil erosion potential, this project was defined and carried out by the Soil Conservation and Watershed Management Research Institute. Accordingly, the watersheds of the seventh category were divided into seven regions or districts, including 1) Eastern Alborz 2) Middle Alborz 3) Western Alborz 4) Central Iran 5) North Zagros 6) Middle Zagros and 7) South Zagros. Long-term sedimen data of 118 hydrometric stations in these areas were analyzed and the amount of sediment in each station was determined by the logged mean load within discharge classes method. According to the amount of river bedload rates and using EPM model, the amount of sediment yield and cosidering sediment delivery ratio of watersheds, the amount of soil erosion were etermined and the soil erosion map of watersheds overlooking hydrometric stations was prepared. Results showed that the average sediment yield and soil erosion in the watersheds overlooking hydrometric stations are 3.3 and 16 tons per hectare per year, respectively. The lowest and highest soil erosion rates of 9 and 32.4 tons per hectare, belong to the Middle Zagros and South Zagros regions, respectively.
Keywords
- Alatorre, L.C., S. Beguería and J.M. García-Ruiz. 2010. Regional scale modeling of hillslope sediment delivery: a case study in the Barasona Reservoir Watershed (Spain) using WATEM/SEDEM. Journal of Hydrology, 391: 109–123.
- Arabkhedri, M., Sh. Hakimkhani and D. Nikkami. 2004. Comparision of some statistical methods in estimation of suspended load in a watershed with snowy-rainy hydrological regime. Research Final Report, Soil Conservation and Watershed Management Research Institute, 63 pages (in Persian).
- Arabkhedri, M., A.V. Khojeini, Sh. Hakimkhani, A.H. Charkhabi and A.R. Telvari. 2009. Estimating and mapping of sediment yield for Iran. Research Final Report, Soil Conservation and Watershed Management Research Institute, 151 pages (in Persian).
- Bahadori Khosroshahi, F. 2012. River suspended and bed load computation guide. No. 590, Vice President of Strategic Planning and Supervision, 158 pages.
- 2012. Erosion by water. Global Soil Erosion, European Soil Data Centre, European Commission, online, https://esdac.jrc.ec.europa.eu/themes/global-soil-erosion.
- Eswaran, H., P. Reich and F. Beinroth. 2001. Land resource of south Asia, stress, quality and population supporting capacity. in: Proceedings of the International Conference on the Managing Natural Resources for Sustainable Agriculture Production in 21st Century, February 14-18, New Delhi, 551-668.
- Fangmeier, D.D., W.J. Elliot, S.R. Workman, R.L. Huffman and G.O. Schwab. 2006. Soil erosion by water. Soil and Water Conservation Engineering, 5th, Thomson Delmar Learning, New York, 134-158.
- Foster, G.R. and L.D. Meyer. 1977. Soil erosion and sedimentation by water, an overview. Proceedings of National Symposium on Soil Erosion and Sedimentation by Water. American Society of Agricultural and Biological Engineers, 2: 1-13.
- 2009. Statistical report on brief resalts of bedload measure of Iranian rivers in 2007-2008. Iran Water Resources Management Company (IWRMC), Ministry of Power, Tehran, Iran.
- Jafari Ardekani, Ali., R. Bayat, S. Nabipay Lashkarian, H.R. Peyrowan, M.H. Mahdian, M. Shariat Jafari, B. Ghermezcheshmeh. 2016. Investigating of performance EPM model in East Alborz Basins. Research Project Final Report, seven reports, Soil Conservation and Watershed Management Research Institute, 77 pages.
- Julien, P.Y. 2010. Erosion and Sedimentation. 2nd, Cambridge University Press, Cambridge.
- Julien, P.Y. 2002. River mechanics. Cambridge University Press, New York, 31-78.
- Kirkby, M.J. and R.P.C. Morgan. 1980. Soil erosion. Chichester, New York, Bridsbane, Toronto, John Wiley and Sons Publications.
- Landscape of watersheds. 2007. Atlas of watersheds, erosion and sediment section. Research Final Report, Soil Conservation and Watershed Management Research Institute, 105 pages.
- Matthews, G. 1999. Sediment source analysis and preliminary sediment budget for the Noyo River. Prepared for: Tetra Tech., Inc., Under Contract 68-C7-0018, Work Assignment # 0-18, Matthews and Associates, P.O. Box 1516, Weaverville, CA 96093, with assistance from: John Coyle and Associates, Inc. Jeff Anderson Engineering, May 1999.
- Moradi, Sh., M. Ghorji and A. Jafari Ardakani. 2014. Evaluation of EPM model efficiency in sediment estimation in Gorganrood Watershed of Golestan Province. MSc Thesis, Faculty of Agricultural Engineering and Technology, Soil Science and Engineering Department, University of Tehran, 120 pages.
- Nikkami, D. 2009. Soil conservation strategic plan. Research Final Report, Soil Conservation and Watershed Management Research Institute, 277 pages.
- Nikkami, D., M. Shabani and H. Ahmadi. 2009. Land use scenarios and optimization in a watershed. Journal of Applied Sciences, 9(2): 287-29.
- Nikkami, D. 2015. Natural resourses and agriculture integrated management in watersheds. Soil Conservation and Watershed Management Research Institute, 49 pages.
- Ouyang, D. and J. Bartholic. 1997. Predicting sediment delivery ratio in Saginaw Bay Watershed. In: Proceedings of the 22nd National Association of Environmental Professionals Conference. May 19-23, 1997, Orlando, FL. pp: 659-671.
- Wischmeier, W.H., and D.D. Smith. 1978. Predicting rainfall erosion losses, a guide to consrvation planning. U.S. Department of Agriculture, Handbook No. 537.
)