Building Oregon

Prospect Diversion Project (Prospect, Oregon)

Prospect Diversion Project (Prospect, Oregon)
LC Subject
Architecture, American Architecture--United States
California Oregon Power Company
Creator Display
California Oregon Power Company (builder/contractor)
This image is included in Building Oregon: Architecture of Oregon and the Pacific Northwest, a digital collection which provides documentation about the architectural heritage of the Pacific Northwest.
Historic Engineering Report for the Prospect Nos. 1, 2, and 4 Hydroelectric Project Automation Project, Jackson County, Oregon. Report prepared by Natalie K. Perrin, Heather Lee Miller; Historical Reserach Associates, Inc., October 2010
Oregon State Historic Preservation Office
Work Type
architecture (object genre) built works views (visual works) exterior views hydraulic structures shed (storage structure) waterways trestles (bridges)
Prospect >> Jackson County Jackson County Oregon >> Pacific Northwest United States
View Date
Attribution-NonCommercial-NoDerivatives 4.0 International
Rights Holder
University of Oregon
Oregon State Historic Preservation Office
Building Oregon
Primary Set
Building Oregon
University of Oregon
From I. Introduction of this document: Prospect Nos. 1, 2, and 4 Hydroelectric Project (Project) is located in Jackson County, Oregon, on the Rogue River and two tributary streams approximately 45 miles northeast of Medford, Oregon, near the town of Prospect. The Project consists of three concrete diversion dams located on the Middle Fork Rogue River (Middle Fork dam), Red Blanket Creek (Red Blanket dam), and the Rogue River (North Fork dam). The dams divert water through approximately 9.25 miles of water conveyance system to a forebay. The forebay supplies water to three powerhouses, with a total capacity of approximately 36.75 megawatts (mW) (3.75 mW from Prospect No. 1 powerhouse, 32 mW from Prospect No. 2 powerhouse, and 1 mW from Prospect No. 4 powerhouse). -- In 1995, the Oregon State Historic Preservation Office (SHPO) determined that Prospect project facilities appeared to meet the eligibility criteria for listing in the National Register of Historic Places (NRHP).2 No formal determination of the project’s NRHP eligibility has been completed, nor have district boundaries or identification of contributing and noncontributing resources been determined aside from inventory conducted as part of the relicensing process and drafting of the Project’s Historic Properties Management Plan (HPMP).3 Based upon a historic context and site history prepared by Historical Research Associates, Inc. (HRA), Prospect Nos. 1 and 2 meet NRHP eligibility criteria as a historic district under Criterion A, with a period of significance extending from 1911 to 1933.4 As defined in the HPMP, the presumed Prospect Hydroelectric System historic district includes the linear water conveyance system, diversion dams, powerhouses, and auxiliary residential and administrative buildings of Prospect Nos. 1, 2, and 4. -- The Prospect Diversion Project (California Oregon Power Company [COPCO] Project No. 2001) was constructed in 1931, and included diversion dams constructed on the Middle and South Forks of the Rogue River as well as Red Blanket Creek. Though the South Fork dam, Prospect No. 3 powerhouse and water conveyance system is regulated as Prospect No. 3 (Federal Energy Regulatory Commission [FERC] Project No. 2337), the bulk of the Prospect Diversion Project was absorbed into what is regulated as Prospect Nos. 1, 2, and 4 Hydroelectric Project (FERC Project No. 2630). -- Ongoing new license implementation plans at the Project will affect resources located within the Prospect Hydroelectric Project historic district. Implementation plans require removal of the Middle Fork, Red Blanket, and Barr Creek gauge shelters, the Middle Fork and North Fork warming sheds, and alterations to the Middle Fork canal headgate and Red Blanket dam. With the exception of the North Fork warming shed, affected project resources were constructed for use during planning of or as part of the Prospect Diversion Project; the North Fork warming shed was built concurrent with the North 2 PacifiCorp, “Historic Properties Management Plan for Prospect Nos. 1, 2, and 4 Hydroelectric Project Relicensing, FERC Project No. 2630,” May 2005, 1, PacifiCorp Headquarters. 3 Ibid.; and PacifiCorp, “Historic Resource Inventory & Assessment Report: Prospect Nos. 1, 2, and 4 Hydroelectric Project Relicensing, FERC Project No. 2630,” 2003, PacifiCorp Headquarters. 4 PacifiCorp, “Historic Resource Inventory & Assessment Report: Prospect Nos. 1, 2, and 4 Hydroelectric Project Relicensing, FERC Project No. 2630,” 2003. Prospect Diversion Project Historic Oregon Engineering Record Fork dam, completed in 1928, and predates other affected project resources. This Historic Oregon Engineering Record (HOER) focuses specifically on the construction of the Prospect Diversion Project.5 This HOER was commissioned by PacifiCorp in consultation with SHPO as mitigation for effects to these resources caused by new license implementation plans.