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<br />Dolores River <br /> <br />geotechnical analysis}. It does however, appear feasible to <br />raise the inadequate segments of the USBR levee. <br /> <br />Table 3 shows the estimated levee improvements needed to <br />provide the 100-year level of protection: (1) the nearest cross- <br />section location; (2) the encroached or project water surface; <br />(3) the minimum freeboard needed to meet FEMA requirements - 4 <br />feet adjacent to bridges and 3 feet elsewhere; (4) the required <br />levee crown elevation (water surface plus freeboard); (5) the <br />existing right bank (or USBR levee crown elevations); (G) how <br />much higher than the existing levee or bank the increase would <br />have to be (in order to have the recommended freeboard above the <br />100-year water-surface elevations); (7) the average height <br />increase between the downstream (next lower numbered) cross- <br />section and the current cross-section; and (8) the approximate <br />length of earthen mounds that need to be rebuilt (or raised in <br />the case of the USBR levees). As indicated in the table, a total <br />of 8,GOO lineal feet of earthen mounds and levees need to be <br />rebuilt or raised an average 4.5 feet to provide the area with a <br />100-year level of protection. <br /> <br />POTENTIAL QUANTITIES AND COSTS <br /> <br />The following quantities and preliminary cost estimates are <br />based on similar levee analyses in western Colorado, including <br />Grand Junction and Lake City. Some costs may be higher due to <br />the relatively remote location or unknown subsurface geotechnical <br />conditions; other costs may be lower. These estimates should be <br />used as a guide only since there may be substantial variation for <br />the cost of feasibility studies and design work (and associated <br />geotechnical studies and testing); preparation of plans and <br />specifications; and for construction supervision and <br />administration. <br /> <br />The quantities listed below assume the following cross- <br />section geometry and construction methods (typical of Corps <br />levees) as shown on Attachment 8. <br /> <br />. A 12-foot crown with a G-inch layer of aggregate road base <br />to provide an inspection/maintenance road. <br /> <br />. A 1V on 2.5H waterside slope. <br /> <br />. A 1V on 2H lands ide slope. <br /> <br />. Soil stripping and an inspection/cutoff trench equal to the <br />levee height. <br /> <br />12 <br />