|Wells, Robert - Rob|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2008
Publication Date: 2/13/2009
Citation: Wells, R.R., Alonso, C.V., Bennett, S.J. 2009. Morphodynamics of headcut development and soil erosion in upland concentrated flows. Soil Science Society of America Journal. 73(2), 521-530. Interpretive Summary: Soil erosion and sedimentation by water are major problems that reduce cropland productivity, degrade water quality, and clog water conveyance structures. The present investigation sought to examine the effect of soil texture on the development and migration of headcut scour holes typical of agricultural fields. Laboratory experiments were performed to understand the role of different soil textural compositions on erosion performance. The objectives of the current study were: (1) to determine experimentally the effect of soil texture and composition on the development, upstream movement, and soil losses associated with actively migrating headcuts in flows typical of upland areas, and (2) to assess the applicability of equations for predicting the characteristics of the headcuts. The results further demonstrate that erosional characteristics of headcuts can be predicted, thus providing the necessary framework for improving soil erosion prediction technology.
Technical Abstract: In agricultural regions, gully erosion is now recognized as becoming a dominant source of soil loss, and the development and upstream migration of headcuts is critical to the initiation, incision, and dissection of these upland areas. The present investigation sought to examine the effect of soil texture on headcut development and migration using four common soils from the southeastern US, tested for bed surface slopes ranging from 1 to 5% and concentrated flow rates ranging from 45 to 71 L min-1. Migration rates ranged from 0.00001 to 0.0025 m sec-1, maximum scour depths ranged from 0.0419 to 0.1481 m, and sediment yields ranged from 0.00017 to 0.0356 kg s-1. Experimental observations were successfully compared with predictive algorithms for material mass balance, jet entry angles, maximum scour depths, and headcut migration rates. These results further demonstrate that modified jet impingement theory can be used to predict the erosional characteristics of headcuts, thus providing the necessary analytical framework for improving soil erosion prediction technology.