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United States Department of Agriculture

Agricultural Research Service

Research Project: TECHNOLOGIES FOR ASSESSING SEDIMENT MOVEMENT & THE INTEGRITY OF FLOOD CONTROL STRUCTURES, STREAMBANKS, & EARTHEN POND-LEVEES & EMBANKMENTS

Location: Watershed Physical Processes Research Unit

Title: Spatial distribution of pipe collapses in Goodwin Creek Watershed, Mississippi

Authors
item Zhang, Tianyu -
item Wilson, Glenn

Submitted to: Hydrological Processes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 20, 2012
Publication Date: July 5, 2013
Repository URL: http://handle.nal.usda.gov/10113/56982
Citation: Zhang, T., Wilson, G.V. 2013. Spatial distribution of pipe collapses in Goodwin Creek Watershed, Mississippi. Hydrological Processes. 27:2032-2040.

Interpretive Summary: Erosion of the inside walls of soil pores can continue until the soil above the void collapses forming a depression on the surface. Such depressions indicate the existence of subsurface erosion and affect surface erosion processes. The objective of this study was to determine the locations of pipe collapses in agricultural fields of Goodwin Creek watershed and their effects on surface runoff. A survey of four parcels of land was carried out to detect pipe collapse locations, sizes, and elevation of the surround drainage area. A total of 145 pipe collapses were found and the density was 0.58 pipes ha-1. The pipe collapses were not uniformly spread around the fields but were mostly located in the flat alluvial plains where the landuse was predominately cropland. The soils were mainly Collins silt loam soil, Falaya silt loam and Calloway silt loam soil. One of the four parcels had 90% of the pipe collapses with a density of 7.7 pipes ha-1. The mean depth, area and volume of these pipe collapses were 0.12m, 0.34m2 and 0.02m3, respectively, and consisted mostly of small collapses with only a few large ones. There was no relationship between the drainage area contributing to the pipe and the slope of the land surface at the pipe. This is clear evidence that the subsurface flow processes that created the pipe collapses was not represented by surface topographic characteristics. The pipe collapses were found to intercept runoff thereby reducing the slope length factors by 6% and the drainage area by 7%. Both of these factors can reduce the sheet and rill erosion, however, the increased subsurface flow could enhance ephemeral gully erosion.

Technical Abstract: Internal erosion of soil pipes can induce pipe collapses that affect soil erosion process and landform evolution. The objective of this study was to determine the spatial distribution of pipe collapses in agricultural fields of Goodwin Creek watershed. Ground survey was carried out to detect pipe collapses and the location, size, and surface elevation was measured with differential GPS. A total of 145 pipe collapses were found and the density was about 0.58 pipes ha-1. The spatial distribution of pipe collapses was not uniform as pipe collapses were located in the flat alluvial plains where the landuse was dominated by cropland. The soils were mainly Collins silt loam soil, Falaya silt loam and Calloway silt loam soil. One of the four parcels had 90% of the pipe collapses with a density of 7.7 pipes ha-1. The mean depth, area and volume of these pipe collapses were 0.12m, 0.34m2 and 0.02m3, respectively, and all these properties exhibited a skewed distribution. The A-S (drainage area-slope gradient) equation, which has been widely used for erosion phenomenon prediction, did not represent pipe collapses in this study as the coefficient of determination was < 0.01. This is clear evidence that subsurface flow is not represented by surface topographic characteristics. The pipe collapses were found to intercept runoff thereby reducing the slope length factors by 6% and the drainage area by 7%. Both of these factors can reduce the sheet and rill erosion, however, the increased subsurface flow could enhance ephemeral gully erosion.

Last Modified: 8/19/2014