Bull Run Hydroelectric Project
dam project on the Bull Run River
The Bull Run Hydroelectric Project was a Portland General Electric (PGE) development in the Sandy River basin in the U.S. state of Oregon. Originally built between 1908 and 1912 near the town of Bull Run, it supplied hydroelectric power for the Portland area for nearly a century, until it was removed in 2007 and 2008. The project used a system of canals, tunnels, wood box flumes and diversion dams to feed a remote storage reservoir and powerhouse. The entire project was removed because of rising environmental costs. Marmot Dam on the Sandy River was demolished in 2007, and the Little Sandy Dam on the Little Sandy River was taken down in 2008.
History and overview
The Mount Hood Railway and Power Company (MHR&P), also known as the Mount Hood Company, began the project in 1906, building the Little Sandy Dam to divert water through a wooden flume, about 3.2 miles (5.1 km) long, to Roslyn Lake. The dam reduced streamflows on the lower 1.7 miles (2.7 km) of the Little Sandy River and blocked all salmon and steelhead access to the upper 6.5 miles (10.5 km) of the river. Roslyn Lake was at 656 feet (200 m) above sea level, about 400 feet (120 m) higher than the mouth of the Bull Run River, at 242 feet (74 m). The 140-acre (57 ha) lake acted as a reservoir for the powerhouse, which was completed and put into operation in 1912, the same year that the MHR&P merged with Portland Railway, Light and Power Company (PRL&P), the predecessor of PGE.
In 1913 PRL&P built a dam on the Sandy River to supplement the Little Sandy Dam. The Marmot Dam, 45 feet (14 m) high, diverted water from the Sandy to the Little Sandy by canal and tunnel, the longest of which ran 4,690 feet (1,430 m) under the ridge between the two rivers.
This brief starts where responsible research should: with the source description of “Bull Run Hydroelectric Project” as dam project on the Bull Run River. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the places & architecture register because the source frames it as dam project on the Bull Run River. Its deeper value depends on whether names, dates, institutions and citations support that framing.
Maps, plans, fabric surveys and administrative records can establish how the site’s name, extent and function changed over time. The source revision retrieved here is dated Aug 7, 2026. The linked authority identifier is Q4996612. Authority coordinates are 45.429, -122.234. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1908, 1912, 2007 and 2008.
Architectural summaries often privilege surviving fabric and can understate demolished phases, contested use or displaced communities. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
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Three-step research path
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Questions for further research
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This entry incorporates text from “Bull Run Hydroelectric Project” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.