REPORT: Performance Testing of Reinforced Turf-Lined Channels

Grass-lined channels have been widely used in roadway drainage systems for many years, in many climates and in a wide range of soil conditions. This is because a grass lining can be selected for the specific climate and soil to provide relatively good erosion protection while also potentially trapping sediments and related contaminants in the channel section. Yet, the long-term behavior of any grass in an open channel lining is directly affected by the health and integrity of the individual plants. Thus, the overall reliability of a vegetative lining may be compromised by “patches” of weak, dead, or up-rooted vegetation.

To minimize the potential for these localized vulnerabilities to lead to overall liner failure, a class of rolled erosion control product (RECP) called a turn reinforcement mat (TRM) has been used to integrate soil, lining material and grass/stems roots within a single, continuous matrix. To make this a long-term solution, the TRM consists of non-degradable materials. Still, the ability of the reinforced turf lining to provide erosion protection changes over time – providing increasing protection as the grass germinates and matures or decreasing protection as storm events degrade the vegetative stand.

This paper presents the performance characteristics for a range of TRMs and unvegetated/vegetated conditions using standardized large-scale test method, ASTM D 6460.

Key words: RECPs, turn reinforcement mat, TRM, erosion control testing, NTPEP, ASTM D 6460