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<br />( <br /> <br />.. <br /> <br />... <br /> <br />'oi <br /> <br />( <br /> <br />'. <br /> <br />L <br /> <br />- 32 - <br /> <br />'. <br /> <br />Agricultural damage, as evaluated, reflects the net loss in <br />income to the landowners and operators in the overflow area subject <br />to damage based on the series of storms expected to occur in a 100- <br />year period. Crop yields and distribution used in the evaluation were <br />based on the Colorado Agricultural Statistics for Mesa County with <br />adjustrrLents by agricultural technicians to fit the information to <br />specific areas and the expected application of technology. <br /> <br />Floodwater and sediment damages to irrigated crop and pasture <br />land in the overflow area subject to damage are becoming relatively <br />minor because of the rapid urbanization of the area. Damage <br />calculations were based upon the area of crop and pasture land flooded <br />under present conditions by selected flood discharges and the damage <br />value per composite acre of crop and pasture land. in the overflow <br />area. The damages obtained were adjusted to account for any expected <br />urbanization and commercialization during the evaluation period. In <br />this evaluation, the overflow area of Indian Wash proper is calculated <br />to be canpletely urbanized or commercialized by the 25th year of the <br />evaluation period. <br /> <br />Off-site benefits due to the prevention of damages from the <br />delay in water delivery or interruption of irrigation services are <br />based on information furnished by the Grand Valley Irrigation Company, <br />the Grand Valley "later Users Association and agricti.l tural technicians <br />familiar with the area. The High Line Canal has sufficient capacity <br />to pass the flood flows of Indian Wash channel under the flume crossing <br />Indian Wash without damage. The Grand Valley Canal flume over Indian <br />Wash (of the Grand Valley Irrigation Co.mpany)has acalculated capacity <br />of 1,650 c.f.s. for free-flow conditions and 1,830 c.f.s. with the <br />water surface at the top of the flume headwall. <br /> <br />. <br /> <br />This flume is a concrete structure built sometime in the early <br />1920's to replace an older structure which was destroyed by a flood. <br />This flood damage was probably the one caused by the stonn of August <br />1921 which had a recorded precipitation of 2.81 inches. <br /> <br />The storm of June 6, 1958,produced an estimated peak discharge of <br />2,200 c.f.s. in the Indian Wash channel at the Grand Valley Canal <br />but did very little damage to the canal or the flume. Therefore, it <br />is estimated that flood peaks of approximately 3,500 c.f.s. are <br />necessary to cause severe damages to the canal and/or the flume, with <br />a resultant delay in irrigation water delivery. <br /> <br />. <br />