Do Engineers and Contractors Have a Choice for Slope Erosion Control?

摘要

Can a hydromulch deliver equivalent or superior performance as compared to a blanket on slope applications? Do contractors and engineers have a choice for equivalent performance between a hydromulch and a blanket? In order to properly analyze these questions, one needs to evaluate objective performance data. The objective performance data that should be evaluated are germination performance and rainfall protection. For a proper comparison two ASTM standards, and variations thereof, were adopted as baseline testing criteria in order to establish performance data regarding germination and rainfall protection. The first standard is ASTM 6459: Standard Test Method for Determination of Rolled Erosion Control Product (RECP) Performance in Protecting Hill_slopes from Rainfall-Induced Erosion and the second standard is ASTM 7322: Standard Test Method for Determination of Rolled Erosion Control Product (RECP) Ability to Encourage Seed Germination and Plant Growth Under Bench-Scale Conditions. Please note: there are not any ASTM standards for determining germination and full-scale rainfall performance values for hydromulches. Obviously, these standards are intended for blankets, but in order to have an "apple" to "orange" comparison these standards were adopted for testing the hydromulch. A blanket and hydromulch were tested under similar conditions. The first product was a high performing hydromulch and the other product was a double netted straw blanket. Both products were tested on TRI Environmental's ASTM 6459 plots. The hydromulch has also been subjected to the rainfall test conditions at San Diego State University's Soil Erosion Research Laboratory (SERL). The double netted straw blanket underwent additional testing at Utah Water Research Laboratory (UWRL). The plot dimensions, rainfall intensities and rainfall durations did vary between the SERL and UWRL laboratories. Even though the SERL and UWRL testing criteria were not identical, it was concluded the hydromulch was a superior product because the SERL testing regime was more stringent and the results for the hydromulch were more desirable. When holding both products to similar standards and various conditions, it was concluded that a mulch can deliver "equivalent", if not superior, performance to a blanket. Obviously, the performance of one product will not predict the performance of another product, so caution is recommended before accepting other mulch products as an "equal" to blankets as the intent of this research is to prove that a hydromulch can deliver equivalent performance to a blanket. Engineers and contractors now have choice - a blanket or high performing mulch.