Performance of Flexible Erosion Control Materials (0-1914-1)

A series of evaluation procedures to determine the field performance of flexible erosion control materials were conducted at the TTI/TxDOT Hydraulics and Erosion Control Laboratory. The objectives of the study were to determine the effect of flexible materials on the germination and growth of native grasses, as well as to determine the effectiveness of the materials to prevent 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 is averaged for every round of data collection. Results include the four rounds of vegetation coverage data or the final round of vegetation data, depending on the analysis level. Researchers calculate the minimum amount of vegetation establishment from statistically analyzing the data set for significant difference ranges to the analysis level.|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 is calculated to achieve the total sediment loss per one hundred square feet of plot area. The report averages the results of each series of simulated design storms for each round of data collection. The resultant of total sediment loss is established by averaging the totals of each round of design storm values. Researchers establish the maximum amount of sediment loss from statistically analyzing the data set for significant difference ranges according to the analysis level.