AUTOMATED OUTLET STRUCTURE DESIGN FOR WINDSOR LAKE TO IMPROVE IRRIGATION OPERATIONS AND ATTENUATE FLOOD FLOWS

摘要

Windsor Lake (Kern Reservoir) serves as a storage facility, an equalizer reservoir for the Greeley No. 2 Canal, and a regional detention pond for the Windsor Basin. Rapid urbanization surrounding the Town of Windsor results in the need for a regional detention pond for a portion of the nearby Law Basin. Windsor Lake is capable of serving this purpose if several feet of reservoir storage are surrendered. The New Cache La Poudre Irrigating Company, NCLPIC (owners of the Greeley No. 2 Canal), and Kern Reservoir and Ditch Company (owners of Windsor Lake) are in agreement with this scenario with the stipulation that the outlet structure is replaced with an automated structure to improve reservoir and canal operations for shareholders. Requirements for the new outlet structure are to control and measure irrigation releases up to the decreed canal capacity of 600 cfs, and serve as the primary spillway for 2 different 100-year flood scenarios. The first scenario models the existing conditions in the basins and the second models the future condition in which both basins are assumed to be fully urbanized. In addition, the Dam Safety Branch of the State Engineer's Office requires the structure to pass a flood event equating to 17% of the Probable Maximum Flood (PMF). Furthermore, the structure is required to be capable of functioning during the winter months to measure and control small releases for augmentation purposes. Two alternative designs were evaluated during a feasibility study. Rubicon Flume Gates'"1, a type of overshot gate, are utilized in the final design to meet the outlet structure requirements. The new structure gives NCLPIC efficient control over the discharges in their system as well as reducing the flood potential for downtown Windsor.