Potential Erosion Assessment of Dastkan Region Using SLEMSA Model

Document Type : Research Paper


1 Assistant Professor of Geomorphology, University of Isfahan, Isfahan, Iran

2 Ph.D in Geomorphology, University of Isfahan, Isfahan, Iran

3 MA. in Geomorphology, University of Isfahan, Isfahan, Iran

4 Ph.D Student in Geomorphology, University of Isfahan, Isfahan, Iran



Extended abstract
1- Introduction
In geographical studies, soil is not only considered as a natural resource, but also it is exposed to a corrupted danger called erosion, so it needs study, guarding and control. On one hand, the concept of erosion, from geomorphological point of view, is referred to processes which shape the earth surface, and on the other hand, it is related to the factors of soil guarding. The fact is that different results are derived from evaluating erosion risks through various methods, and quantity and type of soil erosion also vary from one place to another. These quantities would be very useful for planning.
First Elwell (1978) applied the SLEMSA Model to assess rates of erosion in Zimbabwe. Her research showed that this strategy is acceptable for the study of soil conservation in the country. After Elwell and Stocking (1984 and 1982), this model was used for assessing erosion in North Africa. Igwe et al (1997) to estimate the potential risk of erosion in South West Nigeria compared the USLE and SLEMSA methodology for mapping erosion and indicated the positive consequences of SLEMSA methodology. Josefine Svorin (2003) examined three models of USLE / RUSLE, SLEMSA, Morgan and Morgan- Finney. Mouinou Igue Attanda (2002) Quality of water erosion in lowland humid Benin using the two models, USLE and SLEMSA assessed and has concluded that the model SLEMSA due to the similarity of the results with the results of projects carried out, fit better with tropical there. Igwe et al (1997) examined the use of models to estimate the potential risk of erosion USLE and SLEMSA in mapping erosion in South West Nigeria have paid. The purpose of this study Dastkan watershed erosion rates, erosion, and identify categories of factors are.
2- Methodology
In the first, boundary of the study area was determined, and then through statistical techniques the factors interact in the SLEMSA model were examined. Collecting information and the primary consideration of factors models, and the combination of digital layers, were done.
3– Discussion
The SLEMSA model divides the soil erosion environment into four physical systems: crop, climate, soil and topography. Major control variables are then selected for each system on the basis that they should be easily measurable and the dominant factor within each system (Stocking, 1980). These control variables are subsequently combined into three sub-models; the bare soil sub model, topographical sub model, and the crop sub model. The main model is then simply the three sub models multiplied together. The SLEMSA equation is asfollows:
Z = K * C * X
Z = the mean annual soil loss from the land (in tons.ha-1.yr-1)
K = Erodibility Factor (in tons.ha-1.yr-1)
X = Topographic Factor
C = Crop factor
 4– Conclusion
The present study shows that medium erosion class (5to 40 tonnes per hectare per year) Dastkan watershed is the most of the area. In general we can say the area is low to moderate ability erodible. SLEMSA model for estimating erosion, environmental conditions are examined. These factors in watershed erosion rates in different influence, its role in the model represent different values.
In the region, 5 erosion focuses in the north part were observed. Considering influential factors on these regions showed that the main erosion factor at the risk focuses was at first rain energy and the other factors were the ground gradient and plant covering .In addition, soil fatigue capability, which was the main erosion factor in the region, did not play so much role at the risk focuses .The research finding showed that water erosion is the dominant type of erosion in the region and erosion rate of average 1.412 ton per hectare is lower,  compared to erosion rate of the country.


احمدی، حسن، (1374)، ژئومورفولوژی کاربردی، انتشارات دانشگاه تهران.
اسکندری، منصور، (1380)، پایان نامۀ کارشناسی ارشد، بررسی وکارآیی مدل SLEMSA در برآورد و فرسایش رسوب در حوضۀ سد زاینده رود به وسیلۀ G.I.S، دانشگاه آزاد اسلامی واحد نجف‌آباد.
پورمحمدی املشی، احترام، (1380)، پایان نامۀ کارشناسی ارشد، محاسبه مقایسه‌ای فرسایش در حوضۀ آبریز شلمان رود، به روش PSIAC,SLEMSA,، دانشگاه اصفهان.
 جداری عیوضی، جمشید (1373): ژئومورفولوژی ایران، دانشگاه پیام نور.
حاجی بیگلو، محمد(1370)، برآورد رسوب از طریق فرمولهای تجربی در حوضه آبخیز سفید رود با روش فورنیه، پایان نامه کارشناسی ارشد، دانشگاه آزاد اسلامی واحد نجف آباد.
 خیام، مقصود (1379)، مبانی ژئومورفولوژی، انتشارات مبنا.
 درویش‌زاده، علی (1370)، زمین شناسی ایران، انتشارات دانش امروز تهران.
 رامشت، محمدحسین، (1375)، کاربرد ژئومورفولوژی در برنامه‌ریزی، دانشگاه اصفهان.
 رامشت، محمدحسین، (1384)، نقشه‌های ژئومورفولوژی (نمادها و مجازها)، انتشارات سمت.
 رفاهی، حسینقلی، (1375)، فرسایش آبی و کنترل آن، دانشگاه تهران.
 شایان، سیاوش، (1382)، فرهنگ اصطلاحات جغرافیایی طبیعی، انتشارات مدرسه.
 عابدی، قدرت‌الله، (1377)، بررسی بلایای طبیعی و نقش آن در توسعه پایدار، مجله سپهر شماره 28
 علیزاده، امین، ( 1379)، فرسایش و حفاظت خاک، آستان قدس رضوی.
 کاهکش، مسعود، (1375)، ارزیابی قابلیت فرسایش خاک با استفاده از سنجش از دور و سیستم اطلاعات جغرافیایی مطالعه موردی حوضه آبریز دریاچه سد دز، پایان نامه کارشناسی ارشد، دانشگاه تربیت مدرس.
 کردوانی، پرویز، (1381)، حفاظت خاک، انتشارات دانشگاه تهران.
کرمی، عیسی، (1372)، بررسی و حفاظت خاک و مبارزه با فرسایش خاک، پایان نامه کارشناسی ارشد دانشگاه آزاد نجف‌آباد.
 کیان پور، عباس، (1376)، بررسی پتانسیل فرسایش حوضه چالشتر، پایان نامه کارشناسی ارشد، دانشگاه آزاد اسلامی واحد نجف آباد
 مورگان، آر، پی، سی، (1368)، فرسایش و حفاظت خاک، ترجمه امین علیزاده، انتشارات آستان قدس رضوی.
 میرزائی، مجید، (1380)، ارزیابی فرسایش خاک در سیستم آبخیز دشت نجف آباد با تاکید بر مدل SLEMSA، پایان نامه کارشناسی ارشد، دانشگاه آزاد اسلامی واحد نجف‌آباد.
 Attanda Mouinou Igue (2002),"The Qualitative Assessment of water erosion risk in moist savanna of Benin.12 th ISCO conference Beijing.
 Becher, H. H. (2003),"Estimating soil loss due to erosion by water or wind",US Geologyical survey National water.
 Beven, K. J.(1985),"Distributed models hydrological forcasting",John wiley and sons Ltd, pp. 405-435.
 Cartagena, D. F. (2004),"Remotely sensed land cover parameter extraction for watershed erosion modeling",www.itc.nl
C.AIgwe.F.O.R.AKamigbo,J.S.C.M bagwu(1997). Application of SLEMSA and USLE erosion models for potential erosion hazard mapping in south estern Nigeria, University of Nigeria.
 Ehler, M. (2005)," Remote sensing for environmental monitoring",Interior Environment and Related Agencis,United states, pp. 275
 Elwell, H.A., and Stocking, M.A., 1982: Developing a simple yet practical method of soil-loss estimation.Tropical Agriculture, 59:43-48.
 Elwell HA. 1978. Modelling soil losses in southern Africa. Journal of Agricultural Engineering Research 23: 117–127.
 Elwell, H.A. & Stocking, M.A. (1984) Estimating soil life-span.Trop. Agric. (in press).Farm Management Handbook (1982) Department of Agricultural, Technical and Extension Services, Harare, Zimbabwe.
 Foster, G. R. (1988),"Modeling soil erosion and sediment yield", Soil erosion research methods, Soil and water conservation society, Ankey, Iowa, pp. 97-117
kaiser, C. (1999),"Erosion risk assessment for the Barossa Reservior catchment",North American,s environment, UNEP/Earth print, pp. 230
Malava, J. and Bonda, F. (1999), "Proposal for research to support erosion hazard assessment in Malawi", Agricultureal engineering Bunda College of Agriculture, www.ag.arizona.edu
Mannaerts, C. M. M. (1992),"Assessment of the transterability of laboratory rainfall – runoff and rainfall – soil loss relationships to field and catchment scales". PhD Thesis Gent university Belgium, pp. 210
Paroda, R. S. (1998)," Indian association of soil and water conservationsts" 8th International soils conservation conterence, pp. 1684
Pimetel, D. (1995),"Enviromental and Economic cost of soil erosion and conservation benefits",Science Vol.267, PP.24
Schulze, R.E. (1979) Soil loss in the key areas of the Drakensburg -a regional application of the soil loss estimation model for southern Africa (SLEMSA). In: Hydrology and Water Resources of the Drakensburg, 149-167. Natal Town and Regional Planning Commission, Pietermaritzburg, South Africa.
Stocking, M.A. (1982) Modelling soil losses. Suggestions for a Brazilian approach. UNDP BRA/82/001, Report of the Overseas Development Group, University of East Anglia.
Stocking, M.A., Chakela, Q. and Elwell, H.A., 1988: An improved method for erosion hazard mapping.
Part I: The technique.Geografiska Annaler 70 (A.3): 169-180
Svorin Josfin (2003),A test of three soil erosion models incorporated in to a geographical information system, Hydrological processes17, university of Copenhagen.