PERFORMANCE OF EROSION CONTROL PRODUCTS ON A HIGHWAY EMBANKMENT

Abstract

Unprotected soil at construction sites often results in large rates of erosion. Five different erosion control treatments were tested on the slopes of a highway sedimentation basin to determine their impact on vegetative growth, runoff, and erosion. The treatments were a bare (no treatment) condition, a disk–anchored straw mulch, a wood–fiber blanket, a straw/coconut blanket, and a bonded–fiber matrix product (hydraulically applied). A minimum of three replicates was used for each treatment. Straw mulch was selected as the standard treatment for statistical analyses. The site was planted with native prairie seeds, and the establishment of vegetation was monitored over the growing season. Above–ground biomasses for the bare and straw–mulch treatments were statistically greater than those of the bonded–fiber matrix treatment. Statistically significant differences in above–ground biomass for the other treatments were undetected at the 10% level. Weedy grasses and forbs were the dominant plant species. Runoff and erosion data were collected using a rotating–boom rainfall simulator for spring and fall sets of runs corresponding to little and good vegetative growth, respectively. Runoff depths were generally larger from straw–mulch and bare plots. There were no statistically significant differences in relative runoff depth between the blankets and the bonded–fiber matrix product. Under conditions with little vegetation, erosion from the straw–mulch plots was roughly one–tenth of that from the bare soil plots; erosion from the blanket and bonded–fiber matrix plots was roughly one–tenth of that from the straw–mulch plots. There were no statistically significant differences in relative sediment yield between the blankets and the bonded–fiber matrix. Erosion from bare and straw–mulch treatments was greatly reduced by vegetative growth that occurred between the spring and fall runs.