نوع مقاله : مقاله پژوهشی
نویسندگان
1 استادیار گروه مرتع و آبخیزداری، دانشکده کشاورزی و منابع طبیعی، دانشگاه ارومیه
2 دانشیار گروه مرتع و آبخیزداری، دانشکده کشاورزی و منابع طبیعی، دانشگاه ارومیه
3 دانشجوی کارشناسی ارشد مهندسی حفاظت آب و خاک، دانشکده منابع طبیعی، دانشگاه ارومیه
چکیده
با توجه به اینکه بیشتر مطالعات صورت گرفته در زمینه فرسایش و رسوب در کشور با کارفرمایی ادارات کل منابع طبیعی استانی و پیمانکاری شرکتهای مطالعاتی و اجرایی و با استفاده از مدل نیمهکمی MPSIAC صورت گرفته است، بنابراین، در این پژوهش بررسی نتایج حاصل از مطالعات فرسایش و رسوب با استفاده از مدل MPSIAC در گستره استان آذربایجان غربی مد نظر قرار گرفت. نتایج نشان داد که طی حدود سه دهه گذشته ۷۶ حوزه آبخیز استان با وسعت تقریبی ۴۱۰۰ کیلومتر مربع با استفاده از روش MPSIAC از نظر فرسایش و رسوب مورد مطالعه قرار گرفته است، بهطوریکه برای بخشهای شمالی، مرکزی و جنوبی استان بهترتیب میانگین فرسایشی معادل ۹۵/۱۳، ۳۰/۱۶ و ۵۹/۱۵ تن در هکتار در سال و میانگین مقدار رسوب بهترتیب مقادیر 5.39، 5.64 و 6.09 تن در هکتار در سال برآورد شده است. این در حالی است که با بررسی جزئیترِ مقاومت واحدهای سنگشناسی به فرسایش در حوزههای آبخیز مورد مطالعه و همچنین، دو عامل مهم دیگر از قبیل پوشش گیاهی و نوع کاربری از بین نه عامل مورد توجه در روش MPSIAC، اعتماد به نتایج منتج از این روش را کاهش میدهد. از طرفی، بهعنوان یکی از ضعفهای بزرگ در این مدل ابتدا رسوب ویژه و نسبت تحویل رسوب مورد تخمین قرار گرفته، از طریق آنها فرسایش ویژه نیز بهعنوان یکی از نیازمندیهای مهم در مدیریت فرسایش و رسوب مورد برآورد قرار میگیرد که نتایج را بیش از پیش دچار تردید میکند. بر همین اساس بهعنوان یکی از نتایج کلی، پیشنهاد میشود که سازمان جنگلها، مراتع و آبخیزداری کشور استفاده از مدلهای خانواده USLE بهویژه مدل RUSLE را بهجای مدل MPSIAC، دستکم در برآورد فرسایش، در شرح خدمات مربوطه جایگزین کند و اجرای این مهم نیز از سوی ادارات کل منابع طبیعی استانی جدی گرفته شود.
کلیدواژهها
عنوان مقاله [English]
Investigation of the results of soil erosion and sediment yield studies over the past three decades in the watersheds of West Azerbaijan Province
نویسندگان [English]
- Saeed Najafi 1
- Habib Nazarnejad 2
- Hedieh Mohammadnezhad 3
1 Assistant Professor, Department of Range and Watershed Management, Faculty of Agriculture and Natural Resources, Urmia University, Iran
2 Associate Professor, Department of Range and Watershed Management, Faculty of Agriculture and Natural Resources, Urmia University, Iran
3 MSc Student of Soil and Water Conservation Engineering, Department of Range and Watershed Management, Urmia University, Iran
چکیده [English]
Since most of soil erosion studies in the watersheds are conducted by consultant and executive companies (as contractors) using the semi-quantitative MPSIAC model under the supervision of provincial natural resources and watershed administrations (as employers), so in this study, the results and findings of the aforesaid studies in West Azerbaijan Province were considered. Analysis of the studies showed that in the last three decades a total of 76 watersheds of the province with an approximate area of 4100 km2 have been studied in terms of soil erosion and sediment yield states using the MPSIAC Model. Estimated mean annual soil erosion was 13.95, 16.30, and 15.59 t.ha−1.yr−1 for northern, central, and southern sections, respectively. Meanwhile, based on the model, the mean sediment yield of mentioned sections has been calculated equal to 5.39, 5.64, and 6.09 t.ha−1.yr−1. Nevertheless, a detailed investigation based on the resistance of different lithology units to erosion in the studied watersheds, as well as land use and vegetation cover as the two most important factors of the MPSIAC Model showed less reliability of the reported results. It seems one of most important reasons for such unreliable results refers to one of the most important weaknesses of the MPSIAC model which estimation of the soil erosion is depended on the estimated amounts of sediment yields and sediment delivery ratio. According to our findings, it can be concluded and suggested that the Forests, Rangelands, and Watershed Management Organization should replace the MPSIAC Model, with USLE family models, especially RUSLE, at least in estimating the soil erosion, in the services description of consultant and executive companies. Implementation of this change should also be taken seriously by the provincial natural resources and watershed management administrations.
کلیدواژهها [English]
- MPSIAC
- Provincial natural resources administration
- Soil conservation
- Soil erosion and sediment yield management
- Study and executive company
- Abdillahi, Sh., H. Nazarnejad, M. Miryaghubzadeh and S. Najafi. 2018. Estimates of gully erosion and development using GIS and RS. Desert Ecosystem Engineering Journal, 6(17): 69-78 (in Persian).
- Abdullah, M., R. Feagin and L. Musawi. 2017. The use of spatial empirical models to estimate soil erosion in arid ecosystems. Environmental Monitoring and Assessment, 189(2): 78-96.
- Arabkhedri, M. 2014. A review on effective factors of water soil erosion in Iran. Journal of Land Management, 2(1): 17-26 (in Persian).
- Bagherzadeh, A. and M.R.M. Daneshvar. 2013. Evaluation of sediment yield and soil loss by the MPSIAC model using GIS at Golestan Watershed, northeast of Iran. Arabian Journal of Geosciences, 6(9): 3349-3362.
- Chitsaz, N. and A. Malekia. 2016. Development of a risk-based multi-criteria approach for watershed prioritization with consideration of soil erosion alleviation (case study of Iran). Environmental Earth Sciences, 75(22): 1448-1463.
- Collins, AL. and D.E. Walling. 2004. Documenting catchment suspended sediment sources: problems, approaches and prospects. Progress in Physical Geography, 28(2): 159-196.
- Hakimkhani, Sh. and H. Ahmadi. 2008. Determining sub basins contributions in sediment yield using sediment fingerprinting method, case study: Margan Basin, Poldasht, Makoo. Journal of Agricultural Sciences and Natural Resources, 15(1): 181-191 (in Persian).
- Haregeweyn, N., J. Poesen, J. Nyssen, G. Verstraeten, J. De Vente, G. Govers and J. Moeyersons. 2005. Specific sediment yield in Tigray, Northern Ethiopia: assessment and semi-quantitative modelling. Geomorphology, 69(1-4): 315-331.
- Heshmati, M., A. Arifin, J. Shamshuddin and N.M. Majid. 2012. Predicting N, P, K and organic carbon depletion in soils using MPSIAC Model at the Merek Catchment, Iran. Geoderma, 175: 64-77.
- Najafi, S. 2014. Assessing watershed management position in the five-year development documents of Iran. Extension and Development of Watershed Management, 3(10): 37-45 (in Persian).
- Najafi, S. and S.H.R. Sadeghi. 2013. Comparative study of applying soil erosion mapping, fingerprinting and field measurement techniques in estimation of sediment sources. Journal of Watershed Engineering and Management, 5(3): 165-178 (in Persian).
- Najafi, S., S.H.R. Sadeghi and T. Heckmann. 2017. Temporospatial variations of structural sediment connectivity patterns in Taham-Chi Watershed in Zanjan Province, Iran. Journal of Water and Soil Conservation, 24(3): 131-147 (in Persian).
- Najafi, S., S.H.R. Sadeghi and T. Heckmann. 2018. Analyzing structural sediment connectivity pattern in a Taham Watershed, Iran. Journal of Watershed Engineering and Management, 10(2): 192-203 (in Persian).
- Noori, H., H. Karami, S. Farzin, S.M. Siadatmousavi, B. Mojaradi and O. Kisi. 2018. Investigation of RS and GIS techniques on MPSIAC Model to estimate soil erosion. Natural Hazards, 91(1): 221-238.
- Peyrowan, H.R. and M. Shariat Jafari. 2013. Presentation of a comprehensive method for determining erodibility rate of rock units with a review on Iranian geology. Watershed Engineering and Management, 5(3): 199-213 (in Persian).
- Sadeghi, S.H.R. 2017. Soil erosion in Iran: state of the art, tendency and solutions. Agriculture and Forestry, 63(3): 33-37.
- Sadeghi, S.H.R. and S. Najafi. 2014. Source ascription for fluvial sediment in watersheds (concepts, methods and technologies). Jihad Daneshgahi, 256 pages (in Persian).
- Sadeghi, S.H.R., S. Najafi and A. Riyahi Bakhtiari. 2017. Sediment contribution from different geologic formations and land uses in an Iranian small watershed, case study. International Journal of Sediment Research, 32: 210-220.
- Sadeghi, S.H.R., S. Najafi, A. Riyahi Bakhtiary and P. Abdi. 2014. Soil erosion types ascription for sediment yield using composite fingerprinting technique. Hydrological Sciences Journal, 59(9): 1753-1762.
- Safamanesh, R., W.N.A. Sulaiman and M.F. Ramli. 2006. Erosion risk assessment using an empirical model of pacific south west inter agency committee method for Zargeh Watershed, Iran. Journal of Spatial Hydrology, 6(2): 10-26.
- Tajgardan, T., S.A. Ayoubi and J.S. Shataei. 2008. Soil erosion and sediment yield assessment using MPSIAC Model, remote sensing and geographic information systems, case study: Ziarrat Watershed. Pajouhesh-va-Sazandegi (Iran), 21(79): 37-45 (in Persian).
- Zangeneh, A., J. Sadidi and A. Koshanfar. 2010. An assessment of water erosion of Sarab Sefid Venaee of Bourojerd Watershed by revised MPSIAC. Geografical Journal of Cheshmandez-E-Zagros, 1(2): 55-64.