Otter Creek Dam Rehabilitation

Otter Creek Dam is located 60 miles south of Richfield, Utah. Construction of the dam occurred over 100 years ago during the period of 1897 to 1901. The dam is an earth and rockfill structure with a storage capacity of 52,700 acre-feet.

The Utah State Engineer established new minimum Dam Safety Standards in 1991 and required dam owners to conduct dam safety investigations. The investigation work on Otter Creek Dam in 1997-98 found that the dam was in good condition, but did not meet the new standards for performance under a major earthquake or flooding event.

Design and construction occurred in 1998-2000 to upgrade the embankment, spillway, and outlet works to meet the standards. The total investigation, design, and construction cost of the project was $2,133,000. Financing was provided by the Utah Board of Water Resources in the form of a 95% grant and 5% loan to the Otter Creek Reservoir Company.

The Otter Creek Reservoir Company retained Franson Civil Engineers to perform investigations, prepare designs, and coordinate construction to bring Otter Creek Dam into compliance with the new minimum Dam Safety Standards.

During the preliminary design phase, we coordinated geotechnical investigations and stability analyses of the existing dam, performed hydrologic and hydraulic modeling to assess spillway capacity, coordinated underwater investigation and completed analysis of the outlet works, and evaluated various alternatives to bring Otter Creek Dam into compliance with the minimum standards.

During the design phase, we assisted the Reservoir Company in obtaining funding for the project through the Dam Safety process administered by the Utah Board of Water Resources, prepared plans and specifications for the selected alternatives identified in the pre-design work, and applied for and coordinated permit approval for the construction activities.

To complete the project, we assisted the Reservoir Company in the bid and award process, provided construction review during the rehabilitation of the dam, and prepared record drawings and documents to enable project closeout.

During all of these activities, we coordinated closely with the Reservoir Company and the State Engineer’s office to ensure that cost-effective yet complete solutions were formulated, designed, and constructed.