Evaluation Report of Structures for Deer Creek Dam

摘要

The U.S. Army Corps of Engineers (Corps), Walla Walla District, by agreement with the Nez Perce Tribe (NPT), evaluated dam options for High Falls Reservoir Project (Deer Creek Dam) site. This work is part of the NPT Ponds Project, a fish stocking program to mitigate for anadromous fishery losses due to construction and operation of the Federal Columbia River Power System. The project site is located on Deer Creek in Lewis County, Idaho. The evaluation report develops a conceptual design for two dam options: homogeneous earthen embankment dam and roller compacted concrete dam (RCC). The embankment dam option includes an upstream low-level intake structure, and overflow emergency spillway with a 150-foot long creast. The RCC structure incorporates an integral outlet structure and an integral, 150-foot wide emergency spillway. Concept- level cost estimates show the total cost of the project ranges between 5.0 million to 6.3 million regardless of whether the structure is an embankment dam or a roller compacted concrete dam. Both structures are configured for minimal maintenance, unattended operation, and ease of construction. Consequently the selection of the type of structure is not based on cost but should be based on other factors. Those factors include aesthetics, areal disturbance, operational and maintenance requirements.