Submitted to: ASAE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/12/2000
Publication Date: N/A
Technical Abstract: Parallel, narrow grass hedges were established on the general contour on a strongly sloping small field-size watershed to determine the effects of runoff and sediment loss. The combination of the silt loam soil texture and land surface gradients up to 15% on the watershed cause it to be classified as Highly Erodible Land (HEL). The watershed is continuously cropped, so soil conservation measures are needed to control erosion and sediment loss. Only grass waterways were used for soil conservation prior to the establishment of the grass hedges. Precipitation, runoff, and sediment loss were observed on the cropped watershed from 1975 through 1999. Grass hedges were established in 1991 and 1992. During the recent eight years with the grass hedges on the watershed the mean annual precipitation was 13% greater and the runoff was 52% greater than that for the previous 22-yr without the grass hedges. However, mean annual sediment loss during this period of grass hedges was 43% less than that from the prior period with no grass hedges. The effectiveness of the hedges could have been greater but for the consequences of extreme runoff flow down concentrated flow channels across the hedges. In these concentrated flow zones some established grasses were washed away. While the narrow grass hedges are effective in reducing sediment loss on the broad slopes, they are inadequate to resist the runoff in concentrated flow channels during extreme precipitation events on this strongly sloping watershed. Extra maintenance is needed for the grass hedges in the concentrated flow zones.