PERFORMANCE OF EROSION CONTROL PRODUCTS ON A HIGHWAY EMBANKMENT

Unprotected soil at construction sites often results in large rates of erosion. Five different erosion controltreatments 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 diskanchored straw mulch, a woodfiber blanket, astraw/coconut blanket, and a bondedfiber matrix product (hydraulically applied). A minimum of three replicates was usedfor each treatment. Straw mulch was selected as the standard treatment for statistical analyses. The site was planted withnative prairie seeds, and the establishment of vegetation was monitored over the growing season. Aboveground biomassesfor the bare and strawmulch treatments were statistically greater than those of the bondedfiber matrix treatment.Statistically significant differences in aboveground biomass for the other treatments were undetected at the 10% level. Weedygrasses and forbs were the dominant plant species. Runoff and erosion data were collected using a rotatingboom rainfallsimulator for spring and fall sets of runs corresponding to little and good vegetative growth, respectively. Runoff depths weregenerally larger from strawmulch and bare plots. There were no statistically significant differences in relative runoff depthbetween the blankets and the bondedfiber matrix product. Under conditions with little vegetation, erosion from thestrawmulch plots was roughly onetenth of that from the bare soil plots; erosion from the blanket and bondedfiber matrixplots was roughly onetenth of that from the strawmulch plots. There were no statistically significant differences in relativesediment yield between the blankets and the bondedfiber matrix. Erosion from bare and strawmulch treatments was greatlyreduced by vegetative growth that occurred between the spring and fall runs.