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<br />The hydraulic model identified 8 agricultural areas, totaling 442 acres, as at risk to <br />inundation by Arkansas River flows of 3,000 cfs. Their locations by specific Problem Area are <br />given in Table 4.5 and are depicted on Sheets 1 through 5 (not included within this bound <br />document). Approximately 60% of this acreage was put into production between 1957 and <br />1988, and approximately 9% was placed in production between 1988 and 1996. Worth noting <br />is that flood control operation of John Martin Dam has not changed appreciably since 1957, <br />except that channel capacity was reduced to 3,000 cfs following the 1965 flood. <br /> <br />Table 4-5. Agricultural areas at risk to inundation at 3,000 cfs. <br />Problem Area Number of sites Acres <br /> <br />3 <br />4 <br />5 <br />6 <br />7 <br />All <br /> <br />5 <br />1 <br />o <br />1 <br />1 <br />8 <br /> <br />282 (range 9-90) <br />35 <br />o <br />5 <br />120 <br />442 <br /> <br />Structural Alternative: Berm Rehabilitation <br /> <br />This alternative identified where existing containment berms are inadequate and makes <br />recommendations on correcting this to prevent inundation of adjacent agricultural lands by <br />Arkansas River discharge of 3,000 cfs. Sediment yields were not calculated for this alternative <br />since they would be essentially the same as the existing condition, barring changes to the <br />discharge regime. Locations and quantity estimates are given in Table 4-6. (Locations refer to <br />hydraulic cross-sections on Sheets 1-5). Quantity estimates for this alternative assume 3: 1 <br />sideslope berms to compute earthwork volumes. <br /> <br />Existing berms primarily consist of random-fill material compacted only by traffic and <br />constructed by local or private entities. The recommended rehabilitation assumes construction <br />of similar structures. Because these berms lack drainage blankets and are not fully compacted, <br />they would be susceptible to piping and sloughing when inundated for an extended period. <br /> <br />The Corps of Engineers does not have an authority to facilitate the described berm <br />rehabilitation; however, local interests have the capability to perform the task. <br /> <br />37 <br />