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<br />Methods For Controlling Erosion <br /> <br />e <br /> <br />FIGURE 4. 3 <br /> <br />Soil COVSI ad riprap <br /> <br />Varies <br /> <br />J <br /> <br /> <br />- Soil Layer <br /> <br />Vegetation <br /> <br />N.W.S.~ <br />....... <br /> <br />....' ...' <br /> <br />'''-stone Toe <br /> <br />Covering riprap with soil and seeding it is feasible only if climatic conditions are <br />conducive: to the growth of the plants or supplemental irrigation is practical. The <br />practice lias largely been confined to urban areas where aesthetics is a consideration, <br />and where machine-mowing can replace more expensive hand. mowing maintenance <br />methods. Soil covered riprap seeded with grass pertonns well in situations where flow <br />velocities in the vicinity of the bank do not exceed 4 to 6 fils. Critical velocities vary <br />with the variety of grass used and soil conditions. <br /> <br />Staked R prap - Live stakes of donnant willow, dogwood. or other fast growing species <br />of wood)' vegetation that root from cuttings suited for streambank locations can be <br />tamped into the bank between stones placed for riprap. These stakes will root and grow <br />under suitable conditions and can provide riparian cover with considerable habitat and <br />scenic value. This combined system increases sediment deposition between the rocks <br />and encourages natuIal invasion by native vegetation. Woody vegetation growing along <br />streambanks can provide aesthetic henefits, aquatic habitat, and riparian habitat Aquatic <br />henefits me derived primarily from leaves and woody debris that fall into the stream <br />where they provide a food resomce and cover for fish. There is considerable evidence to <br />indicate that root systems of woody vegetation help to stabilize streambanks and protect <br />them from further erosion. Figure 4-4 shows a typical diagram of staked riprap. <br /> <br />Live staking of riprap has been used successfully for streambank erosion conttol in a <br />variety 01' locations. Live stakings work well on large and small streams wherever riprap <br />protectiol is appropriate. Woody vegetation often invades riprap structures through <br />natuIal succession unless maintenance measures are taken to prevent its growth. <br /> <br />Major conslraints associated with live staking involve bank placement and climatic <br />conditior s, which must be suitable for plant survival and growth. and construction <br />timing alld handling of live plant materials. Live plant cuttings must be instaUed during . <br />the dormant season if they are to survive, and strict requirements must be followed in <br /> <br />30 <br /> <br />Colorado Erosion Control Manual <br />