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4 E R O S I G N & S E D I M E N T C O N T R O L American Green C350, composite-turf reinforcement matting (C-TRM), along the side slopes. The gabion-reinforced dprap was specified as the means of erosion protection in the low flow channel bed. Use of thts type of pro- tection was deemed necessary in this portion of the channel due to an almost constant flow of water and extreme flow-induced shear forces dudng the specified design event. The hydraulic forces In the channel would exceed the permissible values For veg- etation, reinforced vegetation and non-gabionized tiptop. The channel was excavated and reconfigured and two channels were actually constructed. A pilot channel was dug In the base of the lazger channel. The pilot channel cazdes the normal flow of water, while the larger channel carves the overflow during heavy rainstorms. When analyztng a C-TRM for a protect, it is recommended that engi- neers or designers review the manu- facturer's Index and performance test data on the unvege[a[ed and fully veg- etated matting. Additionally ff the mat- ting 55 a composite, the designer should also revew data on its perma- nentstructure (without [he degradable component) to make sure that it wlll satisfy both short-term and long-term requirements. Conventional TAMS should also be reNewed for adequate index and performance properties. This review !s necessary because there are some mattings on the mazket- which aze labeled TRMs ar C-TRMs, yet aze not supported by performance test data or do not meet the Federal Highway Administration's (FHWA) specification outlined in FP-96 far such. In most instances these products permanent structure does net meet the 0.5 inch (12.7 mm) thickness requirement "The C-TRM we specified for use on the Wichita protect is well supported by performance testing on the vegetative reinforcement properties ', The surlaee Installation oT the C-TRM provided immediate erosion control against channel flow before vegetation establishment while also providing an effective mulch layer to enhance seed germination and plant growth. - af tts permanent three-dimensional bottom net and a super heavy duty structure alone, and the unvegetated corrugated Intermediate net, overlaid performance. While the permanent with a heavy-duty top net. This structure also exceeds the FHWA's unique triple net construction forms phystcal specifications for TRMs" prominent ridges across the mattng to states Jednoralski. "This matting is trap sediment and provide a perma- :~ trrlly a permanent TRM that is supple- Went three-dimensional structure for mented with coconut fiber for stem and root reinforcement. The mat improved Immediate erosion protect[on provides long-lasting erasion control and vegetation growth enhancement.' and permanent vegetation reinforce- . Unlike conventional TRMs which ment on .severe slopes with heary consist of .100% synthetic matedals run-off and channels with super-add- (e.g. ;polypropylene, .PVC, nylon), cal flow velocities, GTRMs contain both degradable °The matting not only addressed organic and nondegradable synthetic the long-term turf reinforcement, but components drawing on the erosion also addressed the short-term erosion control, vegetation establishment and protection needs, meaning that if a reinforcement benefits of both erosion heavy rain came the day after they put control blankets and turf reinforce- it down they could feel safe and not ment mattings. The result rs an ero- lose anything in the protect, even sion control system that outperforms before vegetation,' states John E. conventional TRMs white increasing Warren of ASP Enterprises, Inc. in the erosion resistance of vegetation to Kansas City, MO. ASP was the suppli- that of 24° rock tiptop. er of the erosion control materials and A coconut fiber matrix is technology far the protect, stitch-bonded between aheavy-duty "There is a big difference between NovembedDecember 2002 Iand and Water