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Walker to Berry <br />March 30, 1999 <br />Nage 3 of 5 pages <br />channel (will save the structures that are there too). <br />Drop st lure <br />Active erosi <br />undercu= -______ <br />Added drop stn~cture <br />equilibrium <br />Drop <br />2. Add energy dissipating riprap to protect the base of each drop structure. The purpose of this <br />work is to protect new structures from, and save existing structures from additional, undercutting. <br />Geotextile liner underneath, slope of riprap 3 horizontal to 1 vertical. Hides concrete drop <br />structures. <br />Drop st ture Riprap, ?'minimum diameter <br />Drop structur <br />Drop ructure <br />John suggests riprapping the entire reach between drop structures. <br />3. Repair the massive erosion feature (Enclosure 5). Reshape, line with a geotextile fabric, and <br />riprap (Large, like 2-foot diameter rocks, with filter bedding). The purpose of this work is to <br />arrest additional erosion at this site (will also make it look better). <br />4. Install ford crossings at the road (do not use culverts). An upper cut-off wall, discharge apron, <br />energy dissipating basin and channel riprap to the main drainage will be required. The purpose <br />of this work is to arrest erosion at the down stream side of the road, and to reduce road <br />maintenance at these sites (without them, the roads wil I wash out continuously -culverts are <br />avoided due to the large sediment loads from wasting of slopes above). <br />5. Arrest the head-of-project main channel erosion. This will require reshaping, lining with <br />geotextile fabric, and riprap from the vicinity of the sandstone ledge in the main channel level to <br />the base of the slope. The purpose of this work is to arrest erosion in the backfill area. A <br />sandstone ledge will likely arrest head erosion up the undisturbed drainageway. <br />