There had to be a better way
After 28 years with a leading manufacturer of stitched and woven turf reinforcement mats (TRMs), Tim Lancaster set out on his own to develop a more “complete” TRM.
Conventional TRMs, though very effective once they become well vegetated, don’t provide a high level of erosion protection before and during vegetation growth.
Since it may take 6 to 12 months or longer to establish a fully mature stand of vegetation through TRMs, the risk of system failure due to erosion before establishment can be significant.
This is especially true with climate change ushering in more frequent, severe storm events. Tim’s goal was to develop a TRM that would offer much greater immediate, unvegetated erosion protection than the conventional TRM products on the market, in order to meet the challenges posed by today’s extreme weather conditions.
It started with a doormat
Taking a page out of Mother Nature’s playbook, Tim thought a TRM that actually looked like grass and had the texture of grass might perform like grass as well. He envisioned a layer of simulated turf grass blades forming a shear plane above the soil surface that would reduce the erosive forces of flowing water. After noticing an artificial turf doormat at a local hardware store he began some informal research in his backyard to determine if real grass would grow well through this type of artificial turf material
Once verified that grass would grow through this matrix, Tim began working with GrassWorx LLC in St Louis, on prototype development and modifications. A large-scale channel test at TRI Environmental on one of the simulated turf mat prototypes proved his theory. The prototype mat demonstrated unvegetated erosion protection better than any TRM Tim had ever experienced.
This initial test spurred more collaboration and ideation between Tim Lancaster and the GrassWorx engineering team resulting in even greater improvements in the original prototype’s erosion control performance. After several months of research and development, it was time to put the new prototype products through formal hard-core ASTM D6460 channel testing to quantify their erosion control effectiveness.
Test Results Were Remarkable
Results from the initial round of ASTM D6460 unvegetated large-scale channel testing on the new InstaTurf® product (ShearForce™ 10) in a 10% gradient flume and a new scour control mat (ShearForce™ 12) in a 20% gradient flume, were impressive.
Neither product even came close to failure at the highest achievable flow discharge rates TRI’s laboratory could generate (approx 50 CFS). So, in an effort to actually determine a failure point and permissible shear stress rating, at least for the ShearForce10, the product was moved to the 20% gradient flume which can generate much higher shear stresses. Note: When it comes to TRMs, the 20% gradient flumes are typically only used to test fully vegetated TRMs, since unvegetated conventional TRMs normally fail in the 10% flumes.
4x erosion control
Final results from a total of 3 rounds of channel tests on each ShearForce product in the 20% flumes, confirmed the remarkable initial findings. Both products virtually stopped erosion at flow-induced shear stresses well in excess of 10 lbs/sf and velocities exceeding 20 ft/sec. That’s unvegetated erosion protection performance greater than three times that of conventional TRMs and equal to fully vegetated TRMs, tied concrete block mats and rock riprap exceeding 30 inches in diameter.
The new InstaTurf Soft Armor products were ready to bring the world a whole new level of permanent erosion protection for high flow channels, extreme slopes, shorelines, overflow structures and culvert outfalls, against the ever-increasing storms and floods of the 21st century.
GrassWorx, learning from nature, improving lives.