Utah State University

Testing Protocol

This university study used indoor laboratory channel flumes filled with highly erodible, sandy, loam soil, and controlled-volume flow events.

Each channel lining material was subjected to consecutive 0.5-hour or longer flow events until erosion and/or a material failure occurred. Failure within the testing regimes was defined for the different lining materials as follows:

TEST MATERIAL	EROSION FAILURE	MATERIAL FAILURE
Bare Soil Control	0.5 in average soil loss from channel	N/A
Unvegetated Matting	0.5 in average soil loss from channel	Observed tears, rips, or excess fiber loss
Unreinforced 6" Bluegrass Sod	0.5 in average soil loss from channel	Observed tears, scoured out holes
Reinforced 6" Bluegrass	0.5 in average soil loss from channel	Observed tears, scoured out holes

Test Results

Phase 1

Phase 1 is the pre-emergence phase or immediate erosion control provided. This is the time period between seed application and seed germination and emergence. This phase requires effective erosion control and mulching to protect the seed and soil, and enhance seed germination. Typically, the TRM selected for use will provide the sole means of erosion control during this developmental phase.

Maximum Velocity for Unvegetated Mattings at 0.5-Inch Soil Loss

Phase 2

Phase 2 occurs after seed germination and emergence, and continues until the plants become fully mature or established. There is a continued need for the TRM to provide erosion control at the base of the seedlings and in the interstitial soil surfaces between plants. The TRM must also provide structural support and reinforcement to prevent the plants, with their undeveloped root and vegetative structures, from being plucked from the soil.

Estimated Permissible Velocities for Natural and Reinforced Kentucky Bluegrass

Phase 3

Phase 3 is the period during which the vegetation matures and becomes fully established.

Maximum Flow Durations for Reinforced and Unreinforced Mature Vegetation at 18-Feet-per-Second Velocity

Conventional root reinforcement turf data from other manufacturers’ published data
P300 limit reached following 60-hr flow at 14.5 fps

We are a proud participant in AASHTO's National Transportation Product Evaluation Program for RECPs.

GSA Contract Number GS-07F-8870D : 04/01/2004-03/31/2009

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