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ARS Home » Midwest Area » West Lafayette, Indiana » National Soil Erosion Research Laboratory » Research » Publications at this Location » Publication #292491
Title: Subsurface hydrologic effects on sediment deposition

Author
item NOUWAKPO, SAYJRO - University Of Nevada
item LI, ZHAOXIA - Huazhong Agricultural University
item Huang, Chi Hua

Submitted to: Joint Federal Interagency Sedimentation and Hydrologic Modeling
Publication Type: Proceedings
Publication Acceptance Date: 6/17/2014
Publication Date: 4/19/2015
Citation: Nouwakpo, S.K., Li, Z., Huang, C. 2015. Subsurface hydrologic effects on sediment deposition. In: Proceedings of the Joint Federal Interagency Sedimentation and Hydrologic Modeling. http://www.sedhyd.org/2015/proceedings.

Interpretive Summary:

Technical Abstract: Quantification of soil erosion processes has been traditionally focused on soil detachment and sediment transport while efforts in quantifying sediment deposition process are relatively minor. Nevertheless, most sediment generated on the hill slopes are deposited within the field and only a small amount reaches the waterways. Sediment delivery ratio, a term used to describe the portion of the eroded sediment that actually reaches a channel or stream, tends to be in the range of 0.1 to 0.2 for hillslope sediment delivery, indicating the large proportion of eroded sediment being deposited within the field. Current methods to estimate sediment deposition only include sediment and surface flow properties and do not consider the effect of subsurface hydrology, such as seepage and drainage. In a laboratory 9.7-m hillslope where all the surface and subsurface hydrologic components can be controlled, we observed: 1) reduced sediment delivery; and 2) more rapid expansion of the zone of sediment deposition when the soil was free drained as compared to when the soil was saturated and water was seeping out on the surface. This empirical observation triggered the design of a special 5-m soil channel where we could quantify soil erosion and sediment deposition by controlling the amount of sediment that is fed into the soil channel. At low or no sediment feeds, the soil channel had net erosion, and at high sediment feed, part of the sediment couldn’t be transported out of the soil channel, hence net deposition occurred. Our results showed that the soil channel eroded less and deposited more sediment when the soil channel was free drained as compared to when the channel was saturated with a slight surface seepage flow. Findings from the 5-m soil channel were further confirmed in the 9.7-m hillslope box where it was separated into an upslope sediment source area and a downslope erosion/deposition mass-balance area. This research shows that sub-surface hydrology plays a significant role in processes of erosion and sediment deposition. Additionally, subsurface drainage at wet areas can have erosion control benefits, from both reduced soil erosion and enhanced sediment deposition.