1999-03-30_GENERAL DOCUMENTS - C1981037

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Walker to Berry March 30, 1999 Page 4 of 5 pages Intermediate Priority 6. Narrow terraces (6 foot wide), at 20-foot intervals (slope distance), on the sideslopes. The terraces would have a backslope of 10%, and flow at 2% grade to the upper portions of the drainage basin to the main channel. The purpose of this work is to arrest the extensive gully erosion developing on the sideslopes. Narrow terraces are called for to minimize the cut slope into the existing (partially) vegetated slopes. 10% backslopes are specified to minimize blowouts. 2% thalweg to minimize sediment deposition but retard erosion. 7. Plant ponderosa pine seedlings. The purpose of this work is to protect, by reforestation, the �— slopes of the reclaimed areas. Recommend 20-foot spacing on the furrow ditch lower embankments. This might be a Boy Scout or classroom project. Costs: Jim McArdle estimates the drop structures (from previous work) at $5,000 each. 1999 Means is $175/lf= $3,500 (does not account for remote site). The Means estimate for riprap is about $40 per square yard (3' deep). John believes riprap may be available in the Canyon City area for$20 per square yard (3' deep). Membranes are estimated at $7.70 per square yard. Dozer work is estimated at $500/day. Arizona crossings are estimated $3,300 each (cut-off wall, $800, slabs $712, discharge apron $500, riprap and membrane $1300). Design Alternative 1 Add 5 drop structures, protect bases, repair massive erosional feature, place road crossings, stabilize head erosion, furrow ditch slopes, plant trees. 1. 5 @ $5,000 = $25,000 2. 12 @ $564 = $6,800 3. 1/2 dozer day @ $250. Riprap and textile @ $21,000 = $21,250 4. 2 @ $3000 = $6000 5. '/2 dozer day @ $250, Riprap and textile @ $31,000 = $31,250 6. 2 dozer days = 1,000 7. est 20 acres, 100 seedlings/acre @ $0.28 each = $20,000 total = $111,300 Design Alternative 2 Riprap 100 feet below each existing drop structure, repair massive