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<br />Methods I:or Controlling Erosion <br /> <br />e <br /> <br />Vegetatior. can then be planted or allowed to invade naturally. A typical structure of this <br />1cind is illllstrated in Figure 4 - 18. <br /> <br />FIGURE 4-17 <br /> <br />Brush Mat Revetment <br /> <br />Cable <br /> <br /> <br />High Bankline <br />Varies .- <br />I Varies <br /> <br />------1 ca~ <br /> <br />Brush <br /> <br /> <br />Flow <br /> <br />Stone <br /> <br />Tension Collar <br /> <br />NW.S. <br /> <br />tr aambed <br /> <br />~ <br /> <br />Cellular blocks have been successfully used in stream flow up to 15 feet per second. The <br />holes in the blocks limit the potential of failure due to hydrostatic pressure, but <br />turbuleocf may dislodge the blocks if they are not properly placed. Like riprap, cellular <br />block coMorm to minor changes in the bank. However, it is not an economical <br />a1temativt to riJll1lP. Cellular blocks are not adversely affected by massive ice flows. <br /> <br />FIGURE 4-18 <br /> <br />Cellular cc,ncrete blocks <br />Existing Bankl ne <br />Excavation _ <br /> <br /> <br />Soil <br />Cover <br /> <br />Cellula' <br />Concrete <br />Block <br /> <br />~ <br /> <br />~l:'~ <br />;rf Vies <br /> <br />6-8' Typical <br /> <br />1 <br /> <br />Stone Fill <br />lV on 2H <br />T N.W.S. <br />3' Typical <br />1 <br /> <br />Erosion Control Matting - Recommended for protection on upper banklines, erosion <br />control matting (ECM) employs the use of a biodegradable mat to cover the bank. Seed <br />is planted in the stream bank, then covered with the desired ECM. The ECM is then <br />staked or :;tapled to the bank for security. <br /> <br />The ECM, stakes, or the staples can be made of biodegradable materials to provide <br />mulching for the vegetation but provide only temporary bank protection. Erosion <br />control matting is expensive but can be placed by unskilled labor. Erosion contrul <br />matting is not economical for large projects with steep and unstable banks. <br /> <br />e <br /> <br />50 <br /> <br />CoIOradl) Erosion Control Manual <br />