PROCESSES OF HEADCUT GROWTH AND MIGRATION IN RILLS AND GULLIES  

作　　者：Kerry M. Robinson(Plant Science and Water Conservation Research Laboratory, USDA-ARS, 1301 N. Western St., Stillwater, OK 74075, USA)Sean J. Bennett(National Sedimentation Laboratory, USDA-ARS, P.O. Box 1157, Oxford, MS 38655, USA)Javier Casali, and Grego 

出　　处：《International Journal of Sediment Research》2000年第1期69-82,共14页国际泥沙研究（英文版）

摘　　要：The formation and upstream migration of headcuts significantly increases soil losses and sediment yield from agricultural lands, threatens the structural integrity of earthen dams, and can undermine roads and bridges. Recent research using unique experimental facilities and methodologies has provided new insights on these erosion processes. Under controlled experimental conditions, steady-state soil erosion due to migrating headcuts has been simulated for rills and along crop furrows. During migration, headcut shape, size, rate of movement, and sediment yield remained constant. Downstream of the headcut, a soil bed was constructed where slope was dependent upon the sediment yield from the headcut and the flow transport capacity. Soil erosion processes were also examined in a large outdoor facility simulating gully headcuts. Using a compacted cohesive soil, headcut migration rate was observed to decrease as the average density and average unconfined compressive strength increased. While the flow rate and overfall height were not observed to have a major impact on advance rates, a sand layer at the base of an overfall did have a dramatic influence on advance rates. The erosion processes and flow structure within the large gully headcuts were strikingly similar to those in rills and crop furrows. The commonality of form and process in these soil erosion phenomena suggests that erosion prediction technology and mitigation measures may be developed and widely applied.The formation and upstream migration of headcuts significantly increases soil losses and sediment yield from agricultural lands, threatens the structural integrity of earthen dams, and can undermine roads and bridges. Recent research using unique experimental facilities and methodologies has provided new insights on these erosion processes. Under controlled experimental conditions, steady-state soil erosion due to migrating headcuts has been simulated for rills and along crop furrows. During migration, headcut shape, size, rate of movement, and sediment yield remained constant. Downstream of the headcut, a soil bed was constructed where slope was dependent upon the sediment yield from the headcut and the flow transport capacity. Soil erosion processes were also examined in a large outdoor facility simulating gully headcuts. Using a compacted cohesive soil, headcut migration rate was observed to decrease as the average density and average unconfined compressive strength increased. While the flow rate and overfall height were not observed to have a major impact on advance rates, a sand layer at the base of an overfall did have a dramatic influence on advance rates. The erosion processes and flow structure within the large gully headcuts were strikingly similar to those in rills and crop furrows. The commonality of form and process in these soil erosion phenomena suggests that erosion prediction technology and mitigation measures may be developed and widely applied.

关 键 词：Headcut Soil loss Sediment yield Soil Erosion process RILL GULLY 

分 类 号：TV14[水利工程—水力学及河流动力学]