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<br />e <br /> <br />e <br /> <br />e <br /> <br />Department of Transportation (TXDOT) tested it, along with a wide variety of rolled erosion <br />control materials at the Texas Transportation Institute (TTI) independent testing facility. The <br />results of the 1997 Evaluation Cycle were published in March 1998, and the three-dimensional <br />woven geotextile proved to be the top performer at 8 Ibslft2 in flexible channel lining tests. As a <br />matter offact, the product was the only RECP from the 1997 Evaluation Cycle to be approved by <br />the TXDOT for use in channels having shear stresses of up to 8 Ibslft211 The Pyramat section <br />displayed the lowest sedimeat loass (0.78 em (OJ in)) at the 8 Ibslft2 shear stress level of any <br />products evaluated during the testing cycle. The product could not be fully tested in the TTI <br />channels due to channel geometric constraints and limitations that kept TTI from reaching the <br />high performance TRM's published short-term, vegetated shear stress limits to 10 lbslfe. <br /> <br />Because the City of Chattanooga specifies the use ofTRM's in high velocity channels, two <br />projects in particular have been highlighted as success stories. In one instance, the high <br />performance TRM survived heavy rainfalls associated with Hurricane Opal of 12 to 13 ft/sec only <br />days after installation. No damage occurred within the channel and, to date, no re-seeding has <br />taken place despite record rainfalls in the area. <br /> <br />The Applegate Subdivision, in Chattanooga, has experienced ongoing problems with an existing <br />swamp-like channel condition that attracted mosquitoes and other insects into this residential area. <br />The appeal of the natural vegetation surrounding the channel was of utmost importance to the <br />residents. Finding an aesthl~tically pleasing alternative to hard armor, such as concrete or rock <br />rip-rap, was one of the City's main objectives. <br /> <br />By selecting the use ofPyr,unat high performance TRM, the City ofChananooga was able to <br />salvage the existing trees and provide a safer area for the residents' children to play. The <br />vegetated TRM also provided the ability to promote water quality through natural filtration and <br />allow for groundwater recharge. The Applegate Subdivision now showcases a naturally <br />vegetated stream meandering through the neighborhood. <br /> <br /> <br />Over time, RECPs have been developed that prove useful in erosion control when used alone or <br />as mulch or matting to improve the success of vegetative applications. New TRMs have been <br /> <br />-6- <br />