Determination of the Runoff and Suspended Sediment from Two Different Slope Length Using Field Plots

Abstract

In this study, the effect of slope length on runoff and suspended sediment yield has been investigated by using plots on uniform slopes under natural rainfall conditions. From September 2007 to September 2009, during two year-period, measurements were done in Dallıca village experimental area in Bartın province. In this study, six field plots with a width of 1.87 m were used. Three of them were 5.5 m long (short plots) and remaining three were 11.05 m long (long plots). Plots were located on bare soil surface that has no conservative vegetation. During the period of experimentation, a total of 158 rainy days were registered and average annual rainfall amount was 1194.8 mm. Average annual runoff per square meter was 270.81 mm, and 311.27 mm in long and short plots, respectively. Average annual suspended sediment was 809.68 g m-2, and 766.53 g m-2 from long and short plots, respectively. While statistically significant differences were found in runoff amount from plots with different lengths, there were no statistically significant differences in terms of the amount of eroded sediment.

Keywords

• Key Words: Slope length
• Runoff
• Suspended sediment
• Field plot
• Rainfall

Farklı Uzunluktaki İki Yamaçtan Oluşan Yüzeysel Akış ve Askıda Sedimentin Parsel Yöntemi Kullanılarak Belirlenmesi

Abstract

Bu çalışmada doğal yağış koşulları altında düz eğim şekline sahip yamaçlarda, yamaç uzunluğunun yüzeysel akış ve askıda sediment üretimine etkisi araştırılmıştır. Bartın ili Dallıca köyü içinde yer alan deneme alanında, Eylül 2007 ile Eylül 2009 tarihleri arasında iki yıl süreyle ölçümler yapılmıştır. Çalışmada genişlikleri 1.87 m olan üç tanesi 5.5 m uzunluğunda (kısa parsel), üç tanesi 11.05 m uzunluğunda (uzun parsel), toplam altı adet arazi parseli kullanılmıştır. Parseller, koruyucu bitki örtüsünün olmadığı çıplak arazi yüzeyine tesis edilmiştir. Çalışma süresi boyunca 158 gün yağmurlu olup, düşen yıllık ortalama yağmur miktarı 1194.8 mm olmuştur. Uzun parsellerde metrekareden yıllık ortalama 270.81 mm, kısa parsellerde ise 311.27 mm yüzeysel akış gerçekleşmiştir. Parsellerden taşınan yıllık ortalama askıda sediment miktarı uzun parsellerde 809.68 g m-2, kısa parsellerde ise 766.53 g m-2 olmuştur. Farklı uzunluktaki parsellerden oluşan yüzeysel akış miktarında istatistiksel olarak farklılık bulunurken, taşınan askıda sediment miktarı bakımından istatistiksel anlamda farklılık bulunmamıştır.

Keywords

• Yamaç uzunluğu
• Yüzeysel akış
• Askıda sediment
• Arazi parseli
• Yağmur

References

1. Bagarello V, Ferro V (2010) Analysis of soil loss data from plots of differing length for the Sparacia experimental area, Sicily, Italy. Biosystems Engineering, 105: 411-422.
2. Balcı AN (1996) Toprak Koruması, İ.Ü. Yayın No: 3947, İstanbul, 490 s.
3. Bryan RB, Poesen J (1989) Laboratory experiments on the influence of slope length on runoff, percolation and rill development. Earth Surface Processes and Landforms, 14: 211-231.
4. Chaplot VAM, Le Bissonnais Y (2003) Runoff features for interrill erosion at different rainfall intensities, slope lengths, and gradients, in an agricultural loessial hillslope. Soil Science Society of America Journal, 67: 844-851.
5. Çepel N (1996) Toprak İlmi, İ.Ü. Yayın No: 3945, İstanbul, 288 s.
6. Fang HY, Cai QG, Chen H, Li QY (2008) Effect of rainfall regime and slope on runoff in a gullied loess region on the Loess Plateau in China. Environmental Management, 42: 402-411.
7. Fangmeier DD, Elliot WJ, Workman SR, Huffman RL, Schwab GO (2005) Soil and Water Conservation Engineering, Fifth Edition, Thomson Delmar Learning, Clifton Park, NY, USA 502 pp.
8. Ghahramani A, Ishikawa Y (2013) Water flux and sediment transport within a forested landscape: the role of connectivity, subsurface flow, and slope length scale on transport mechanism. Hydrological Processes, DOI: 1002/hyp.9791.

9. Gomi T, Sidle RC, Ueno M, Miyata S, Kosugi K (2008) Characteristics of overland flow generation on steep forested hill slopes of central Japan. Journal of Hydrology 361: 2752
10. Kinnell PIA (2000) The effect of slope length on sediment concentrations associated with sideslope erosion. Soil Science Society of America Journal, 64: 1004-1008.
11. Kinnell PIA (2007) Runoff dependent erosivity and slope length factors suitable for modelling annual erosion using the universal soil loss equation. Hydrological Processes, 21: 268126
12. Lal R (1982) Effects of slope length and terracing on runoff and erosion on a tropical soil. Recent Developments in the Explanation and Prediction of Erosion and Sediment Yield (Proceedings of the Exeter Symposium, July 1982) IAHS Publication Number, 137: 23-31.
13. Lal R (1988) Effects of slope length, slope gradient, tillage methods and cropping systems on runoff and soil erosion on a tropical alfisols: preliminary results. Sediment Budgets (Proceedings of the Porto Alegre Symposium, December 1988), IAHS Publicution Number, 174: 79-88.
14. Lal R (1997a) Soil degradative effects of slope length and tillage methods on alfisols in western Nigeria I. Runoff, erosion and crop response. Land Degradation and Development, 8: 2012
15. Lal R (1997b) Soil degradative effects of slope length and tillage methods on alfisols in western Nigeria III. Soil physical properties. Land Degradation and Development, 8: 325-342.
16. Le Bissonnais Y, Cerdan O, Lecomte V, Benkhadra H, Souchere V, Martin P (2005) Variability of soil surface characteristics influencing runoff and interrill erosion. Catena, 62: 111-124.
17. Liu BY, Nearing MA, Shi PJ, Jia ZW (2001) Slope length effect on soil loss for step slopes. In Stott DE, Mohtar RE, Steinhardt GC. (ed) Sustaining the global farm. Selected papers from the 10th international soil conservation organization meeting held on May 24-29, 1999 at Purdue University and the USDA-ARS National Soil Erosion Research Laboratuary: 784-788.
18. Martinez-Zavala L, Jordan A (2008) Effect of rock fragment cover on interrill soil erosion from bare soils in Western Andalusia, Spain. Soil Use and Management, 24: 108-117.
19. Moreno-de las Heras M, Nicolau JM, MerinoMartin L, Wilcox BP (2010) Plot-scale effects on runoff and erosion along a slope degradation gradient. Water Resources Research, 46, W0450
20. Parsons AJ, Wainwright J, Powell DM, Kaduk J, Brazier RE (2004) A conceptual model for determining soil erosion by water . Earth Surface Processes and Landforms, 29: 1293-1302.
21. Parsons AJ, Brazier RE, Wainwright J, Powell DM (2006) Scale relationships in hillslope runoff and erosion, Earth Surface Processes and Landforms, 31: 1384-1393.
22. Phillips JD (1990) Relative importance of factors influencing fluvial soil loss at the global scale. American Journal of Science, 290: 547-568.
23. Rejman J, Brodowski R (2005) Rill characteristics and sediment transport as a function of slope length during a storm event on loess soil. Earth Surface Processes and Landforms, 30: 231-239.
24. Renard KG, Foster GR (1983) Soil conservation: principles of erosion by water. Dryland Agriculture-Agronomy Monograph, 23: 1551
25. Stomph TJ, De Ridder N, Van de Giesen NC (2001) A flume design for the study of slope length effects on runoff. Earth Surface Processes and Landforms, 26: 647-655.
26. Van de Giesen N, Stomph TJ, De Ridder N (2000) Scale effects of Hortonian overland flow and rainfall-runoff dynamics in a West African catena landscape. Hydrological Processes, 14: 165-1
27. Wischmeier WH, Smith DD (1978) Predicting rainfall erosion losses. A guide to conservation planning. USDA Agricultural Handbook 537, U.S. Department of Agriculture. Washington DC, 58 s.
28. Young RA, Wiersma JL (1973) The role of rainfall impact in soil detachment and transport. Water Resources Research, 9: 1629–1636