Performance of Flexible Erosion Control Materials and Hydraulic Mulches (0-1914-2)

The TTI/TxDOT Hydraulics and Erosion Control Laboratory conducted a series of evaluation procedures to determine the field performance of flexible erosion control materials. The objectives of the study included determining the effect of flexible materials on the germination and growth of native grasses and evaluating the effectiveness of the materials for the prevention of erosion on typical steep, roadside slopes before the establishment of permanent vegetation. Researchers repeated the vegetation establishment and soil retention portions of the evaluations on two soil types with the option for two different slopes according to the manufacturer's preference.|Researchers conducted the vegetation establishment evaluation by hydraulically applying the seed and fertilizer mixture on the plot, installing the erosion control product according to the manufacturer's published literature, and collecting data periodically throughout the growing season. The apparent vegetative cover of each plot was averaged for every round of data collection. Results included the four rounds of vegetation coverage data or the final round of vegetation data, depending on the analysis level. Researchers calculated the minimum amount of vegetation established by statistically analyzing the data set for significantly different ranges in the coverage data.|Researchers conducted the erosion control portion of the study by artificially simulating various rainfall events with the greatest probability of occurrence during highway construction periods. The total dry sediment weight was calculated to achieve the total sediment loss per one hundred square feet of plot area. Researchers averaged the results of each series of simulated design storms for each round of data collection. The resultant total sediment loss was established by averaging the totals of each round of design storm values. Researchers established the maximum amount of sediment loss from statistically analyzing the data set for significantly different ranges according to the analysis level.