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ECTC members ‘cover’ geosynthetic applications with TRMs

ECTC News | July 1, 2024 | By: Kurt Kelsey

FIGURE 1 Turf reinforcement mats (TRMs) in a high flow channel with sediment caught in the mat after the first few flow events. Photo courtesy of ECTC.

The Erosion Control Technology Council (ECTC) is a leading industry organization home to top manufacturers of erosion and sediment control products, component suppliers, material distributors and test laboratories. Several members of ECTC either manufacture, distribute, test, provide components for or directly work with turf reinforcement mats (TRMs), which are a type of geosynthetic. ECTC members are dedicated to advancing knowledge, experience and expertise of erosion and sediment control.

The nonprofit organization’s mission is to develop performance standards, uniform testing procedures and guidance on the application and installation of hydraulic erosion control products (HECPs), rolled erosion control products (RECPs) and sediment retention fiber rolls (SRFRs). ECTC recently expanded its reach to other technologies and promote the use of erosion and sediment control products through industry leadership and education in the hope of making a substantial contribution to the science of erosion control and environmental preservation.

Geosynthetic TRMs are versatile products that serve many applications and typically are used to elevate the performance capabilities of vegetation in a variety of steep slope and concentrated flow applications. It is important to keep the “T” in “turf reinforcement mats” by properly preparing the soil bed, applying amendments according to soil test results and following manufacturers’ installation recommendations whenever possible. 

TRMs have been established by the United States Environmental Protection Agency (EPA) in its Storm Water Technology Fact Sheet entitled “Turf Reinforcement Mats” to provide an effective, economical and aesthetically pleasing alternative to hard armor (i.e., rock riprap). Suitable applications are performance-verified by engineers for erosion control in areas where forces exceed the capabilities of naturally occurring vegetation and stormwater conveyances. TRM-reinforced vegetation provides numerous benefits over traditional riprap channels.

FIGURE 2 TRM-reinforced vegetation on landfill cap. Photo courtesy of ECTC.

The main differences between TRM reinforced vegetated swales and riprap channels are the following:

  • Aesthetics (vegetation vs. rock)
  • Safety (vegetation is softer than rock)
  • Maintenance (easier and less expensive with vegetation)
  • Easier accessibility with TRM-reinforced vegetated swales
  • Temperature of runoff; pollution of waterbodies with heated runoff can occur with riprap
  • Temperature in and around TRM-reinforced vegetated swales are cooler than hard armor channels that create heat islands
  • Stormwater quality improvements with TRM-reinforced vegetated swales
  • Infiltration with vegetation to keep water within the watershed
  • Carbon sequestration with vegetation
  • Sod has been placed under and over TRMs before (this would not work with riprap) 
  • Vegetated TRM swales commonly serve as beneficial pollinator corridors
  • Wildlife habitat differences
  • Less destructive installation with TRMs
  • TRMs installations return sites to preconstruction vegetated conditions, not imported rock
  • Shipping and installation; TRMs require significantly less transportation and use of heavy machinery
  • Cost; riprap is more expensive to ship and install (typical installed cost of 33% or more depending on region, size of rock required, etc.)

In addition, the use of TRM-reinforced vegetation furnishes a soft armor, value-engineered option to hard alternatives by effectively reducing construction times, material costs, equipment requirements and most importantly, improving water quality, groundwater recharge capabilities and other sensitive issues involving water quality.

Some TRMs are rated for slope applications as steep as 0.5H:1V, which covers a wide swath of project conditions. According to ECTC specifications, TRM categories have vegetated permissible shear stress test values ranging from 6 lb/ft2 on the lower end of the TRM performance spectrum to at least 14 lb/ft2 vegetated permissible shear stress test value on the high end of the TRM performance spectrum.

FIGURE 3 Installation of turf reinforcement mats (TRMs) with earth percussion anchors on levee. Photo courtesy of ECTC.

The vegetated permissible shear stress is from ASTM or other independent testing the engineer deems acceptable. Large-scale performance testing involves limited soil types and vegetated stands, thus it is recommended that an appropriate factor of safety be used in design and product selection.

Other more specific applications where TRMs have provided successful solutions to challenging conditions in the past are in:

  • Intermittent high flow channels
  • Levees
  • Landfill covers
  • Shorelines (lakes, rivers, ponds etc.)
  • Solar field drip lines and conveyances
  • Pipeline slopes
  • DOT slopes and ditches
  • Fly ash pond covers
  • Outfalls
  • Dams
  • Spillways
  • Railbeds

These are only select examples of where versatile TRMs provide high-performing, green, soft solutions to help protect natural resources.

ECTC members are committed to providing high-performing TRMs and other technologies. Please email ECTC at to learn more about members, tools, services and sustainable solutions the group provides. In addition, there is a complete toolbox of specifications, CAD files, installation videos, fact sheets etc. online at the new website:

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