PROJ00048 - Laserfiche WebLink

Home Browse Search

1979-1980, which area records show was also an above average snowfall year, a "best estimate" yearly runoff curve was derived (see Figure 3). This "best estimate" is derived by using the previously determined ratios of wet to dry year flow rates for Grizzly Creek and applying the ratio as a reduction factor to the wet year flow rates at the gaging site. This results in an average annual flow rate of 5.5 cfs for the middle fork of Arapahoe Creek, with a dry year annual average of 2.2 cfs and a wet average of 8.7 cfs. Because the gaging station site for the middle fork of Arapahoe Creek was located downstream of the proposed dam site, the drainage area ratios were used as a reduction factor to estimate2the flow rates at the da~ site. This ratio (4.91 m Hyannis D.A. / 6.28 m gaging site D.A. = 0.78) results in an aver- age annual flow rate at the dam site of 4.3 cfs. , "i C. Water Rights Meyring and Arapahoe Livestock Companies control conditional storage decrees totalling 2122.7 acre- feet at the Hyannis Reservoir site, and they have applied for an additional 736.5 acre-feet (Appendix B, Attachments 1 and 2). Because Hyannis Peak and the middle fork of Ara- pahoe Creek are tributary to the North Platte River, the storage of water is affected by U. S. Supreme Court cases involving the apportionment of North Platte waters between the three states through which it flows--Colorado, Wyoming & Nebraska. As affects this project, the state of Colorado is prohibited from storing or permitting storage of more than 17,000 acre-feet of water for irrigation purposes from the North Platte and its tributaries in Jackson County, Colorado. ,',__L -:J '. i Information obtained from the Division Engineer in Steamboat Springs (Appendix B, Attachment 3) shows that the largest amount historically stored in North Park was 13,642 acre-feet in 1974-75. There is 32,635 acre-feet of absolute decreed storage in the Colorado North Platte Drainage, of which 7,126.5 acre- feet are not being stored because of reservoirs not built to maximum capacity or which have become unusa- ble. In addition, 12,445 acre-feet are conditionally decreed, including the 2122.7 acre-feet of Hyannis. The Division Engineer indicated that there is a possibility that in two or more consecutive drought years, a lower priority ranked reservoir (720 vs. -14-