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<br />Flow Deflection Technlqu_ - <br /> <br />e <br /> <br />FIGURE 4. 11 <br /> <br />Hardpoint <br /> <br /> <br />v V <br /> <br /> <br />Backfill <br /> <br />, <br />".-- <br />__yanes <br />, <br /> <br />15-20' Typical <br /> <br />lL <br /> <br />L2-3'TypiCal <br /> <br />Existing <br />BanIdi <br /> <br />Varies <br /> <br />15-20' Typical <br /> <br />Varies <br /> <br />J <br /> <br /> <br />Backfill <br /> <br />Stone Fill <br /> <br />Root <br /> <br />Spur <br /> <br />An example of these types of structures can be found in Figures 4 - 11. These structures <br />were used in a reach of the South Platte River in Littlelon, Co. <br /> <br />Type I Deflector . The term "type 1 deftector" refers to a biangular wing.shaped <br />hardpoint angled slightly downstream. These structures serve to concentrate flow during <br />low flow periods and create a scour pool immediately below the tip of the deflector, <br />They are constructed of graded stone piles with boulders placed along the upstream face <br />and the riverward end of the structure. Type 1 crib deflectors extend into the channel and <br />slope from above the bed at the riverward end to bank high at the root. <br /> <br />Type 2 Deftector - The term "type 2 deflector" refers to a deflector much larger than a <br />type 1 deflector but with a lower profile, genera1ly less than two feet above the channel <br />bottom as shown on the contract drawings. They are constructed by placing a peaked <br />stone section of graded riprap around the perimeter of the structure. The interior of the <br />structure is backfilled with a SOil/spall mixture and topped with ftood-tolerant <br />vegetation. The upstream face of the deftectors is armored with boulders. <br /> <br />. <br /> <br />Colorado Erosion Control Manual <br /> <br />39 <br />