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<br />001820 <br /> <br />I <br /> <br />ESTIMATED COSTS <br /> <br />Quantity and Unit Costs <br /> <br />Quantities and costs have been estimated for the conceptual plan. <br />Quantities were estimated based on a typical levee section using 3:1 <br />side slopes and compared to the cross sections used in the hydraulic <br />model. Quantities were computed on a cubic yard per lineal foot basis <br />for 1 evee excavat ion, 1 evee embankment and ri prap. Cl eari ng and <br />vegetati on were est imated on a square foot per 1 i nea 1 foot bas is and <br />converted to acres. Excavation of sandbars were computed in cubic <br />yards, based on cross sections, aerial photos and field observations. <br />Fencing quantities were based on aerial photographs and field <br />observations. Special structures were estimated based on field <br />observation and knowledge of the area drainage system. <br /> <br />Seepage control was considered on a lineal foot basis as outlined in <br />the previous section. A cutoff trench with a clay slurry was assumed <br />20-feet deep and 2-feet wide, based on input from the Portland Cement <br />Association (Ref. 8). While the 20-foot depth likely will not provide <br />a total cutoff to an impervious layer, it would provide a longer flow <br />path for seepage waters. <br /> <br />Unit costs for the major components of the conceptual plan are shown <br />in Table 5. Excavation costs are based on disposal of materials <br />withi n the project 1 ength, outs i de of the 1 evees . Levee embankment <br />material is estimated as clay material hauled from a pit within 10 <br />miles of Alamosa. Seepage control is based on use of clay material in <br />a trench 2-feet wide, 20-feet deep. Clearing and revegetation is <br />based on clearing of mostly brush and some trees. Fencing is based on <br />a combination of barbed wire and chain link fencing. Riprap costs <br />include consideration of hauling from a regional quarry. <br /> <br />Construction contingencies are based on 25% of the construction cost <br />subtotal. The 15% engineering cost is intended to include preliminary <br />and final design and construction related services. <br /> <br />Ri ght-of-way costs were not consi dered to be a factor in the cost <br />estimates. City and County officials will attempt to acquire <br />construction, access and use easements from property owners along the <br />1 evee a 1 i gnment in exchange for removi ng those property owners from <br />the floodway and floodplain. Efforts to gain access to the levees for <br />construction and maintenance should begin immediately. <br /> <br />Table 6 shows the estimated quantities of the key construction items <br />for selected reaches along the river. <br /> <br />-28- <br />