The 4.6-MW Prospect No. 1 hydroelectric project started generating power in 1912. One hundred years and a rich history later, it’s still in action and new licensing will allow it to continue providing a clean power source to Oregon residents for many years to come.
By Tom Gauntt
For 100 years, PacifiCorp’s 4.6-MW Prospect No. 1 plant has provided a reliable source of clean, renewable power to the communities of southern Oregon. Prospect No. 1 began operation in 1912, and improvement measures included in the new Federal Energy Regulatory Commission operating license, issued in 2008, will carry the project forward for the next 30 years.
“One of the really unique things about this project is its soft environmental footprint,” says Monte Garrett, hydro compliance program manager. “The extensive fish passage improvements required at some of our other facilities aren’t necessary at Prospect because it has such minimal impact on fish, wildlife, and other natural resources.”
The Prospect Hydroelectric Project is on the Rogue River and two tributary streams about 45 miles northeast of Medford, Ore. The project consists of three concrete dams that divert water through more than 9 miles of water conveyance system to a forebay, which supplies water to three powerhouses – Prospect No. 1, Prospect No. 2 and Prospect No. 4. Prospect No. 3, though nearby, operates under a separate FERC license. The Rogue River system has a 52 MW net capacity.
|The original wooden structure of the powerhouse at Prospect No. 1, constructed in 1912, still stands on the banks of the Rogue River.|
Settlement of Jackson County, Ore., began with the discovery and development of gold mines in the 1850s. During that decade, brothers Charles and Frank Ray established the Braden Mine and Mill in what is now the town of Gold Hill. Timber companies, farmers and other developers followed.
By 1870, homesteaders and timber interests had formed the town of Deskin, now Prospect, on the banks of the Rogue River. In addition to its location among vast tracts of marketable sugar pine, the community lay on the Old Fort Road, southern Oregon’s primary thoroughfare between the mining community of Jacksonville and the U.S. Army’s Fort Klamath on the east side of the Cascade Range. Travel on Old Fort Road was difficult, however, as it was primitive and primarily built for horse and cart traffic and not heavy wagons. Regional development proved slow, largely limited to scattered ranches, modest tourist facilities and logging camps.
Encouraged by technological advances in hydroelectric power production elsewhere in the country to supply plants and street car lines, and frustrated by the cost and limitations of steam power, the Rays initiated hydroelectric development on the Rogue River around 1900. By 1902, they had completed construction of Gold Ray Dam, which was located halfway between Prospect and Medford. (This dam was decommissioned in 1972 and was removed in 2010.)
Power production on the Rogue River grew when the brothers constructed the Prospect Hydroelectric Plant (now Prospect No. 1) in 1911. The facility consisted of a single 3.75-MW turbine-generator unit in a powerhouse located about 1,400 feet from the nearest impoundment. Three 40-foot-high dams were constructed to feed into the powerhouse.
In a 1963 retrospective, the Medford Mail Tribune described construction of Prospect as “a difficult undertaking involving a 43-mile equipment haul from Medford to the powerhouse site, a haul completed by three- and four-horse teams and wagons, and terminating in a 200-foot drop, achieved by tram.”
Prospect No. 1 not only powered the Ray brothers’ milling operation but also provided electricity to the communities of Medford, Jacksonville, Central Point, Grants Pass and Ashland, directly contributing to the region’s early 20th-century agricultural boom.
Developments over the years
In 1912, the California Oregon Power Company – a Pacific Power predecessor better known as COPCO – purchased the Rays’ interest in the Prospect plant to add to their hydro holdings on the Klamath River and eventually the Umpqua River. In 1926, COPCO began expanding the Rogue River hydro project.
New facilities included the North Fork diversion dam and pond, 7,000 feet of canal, a forebay, 3,100 feet of woodstave flowlines and flumes, a surge tank, penstocks, and the 36-MW Prospect No. 2 powerhouse. A bypass manifold at the surge tank also diverted water to the Prospect No. 1 plant to increase generating capacity at that site.
As southern Oregon grew, so did the need for electricity. By September 1924, survey crews were exploring the area around the Middle and South Forks of the Rogue River in anticipation of further expansion on behalf of COPCO for the South Fork Development, also known as Prospect No. 3. Simultaneously, preliminary geological reports were conducted for regulation, diversion, pond installation and storage projects being considered for further expansion of Prospect No. 2. Of the projects considered, only the diversion project, encompassing the South Fork Development and subsequently Prospect No. 3, would ultimately be undertaken.
In an initial Prospect No. 2 planning report, an engineer described both the original design and construction and plans for development using water from the Middle Fork and South Fork of the Rogue River and Red Blanket Creek:
“The Company’s water right, which dates back to about 1911, was for 400 cfs, but it is proposed to develop the plant for 500 cfs from the North Fork of the Rogue River and about 300 cfs from South and Middle Forks of Rogue River and Red Blanket Creek. … By an exchange of property with the Rogue River Timber Company on November 10, 1925, all of the land necessary for the development of Prospect Number Two from the North Fork was obtained, along with a strip of land 500 feet wide, covering all of the Rogue River Timber Company property between the Middle Fork of Rogue River and the North Fork, also a canal right of way between Red Blanket and Mill Creek that simplifies the picking up of the Red Blanket water. A 15,000 KW unit can be installed in Prospect Number Two without making the diversion from the South Fork [ultimately completed as Prospect Three]. It is proposed to make this installation and continue to operate Prospect Number One by passing water from the new flow conduit [redwood stave flow lines] into the old forebay. [During] a very dry year … all of the flow would pass through the new plant.”
|The Allis Chalmers horizontal Francis turbine inside the powerhouse drives a 4.7-MW capacity generator.|
By January 1928, the work was completed and resulted in considerable local fanfare and laudatory press in the journal Power Plant Engineering, which reported: “All supplies and equipment had to be trucked in, a distance of about 45 miles from Medford. Due to soil conditions, trucking except on the surfaced highway was impossible, so that after the right of way was cleared, a narrow gage track was built from the camp up to the diversion dam site. A rock crushing and cement mixing plant was erected at the dam and rock was crushed and concrete for the project, as far as the forebay, was mixed at this plant and distributed on the narrow gage by means of cars and gasoline locomotives. … The canal [7,000 feet between the diversion dam and forebay] was dug with steam shovels [and] trimmed by hand.”
The Medford Mail Tribune reported in 1963, “There are still persons in the valley who worked on the project [and] remember the period as the most exciting one in the industrial development of Jackson County.”
In 1931, the Prospect Diversion Project was completed. This work supplied additional water to the Prospect No. 1 and No. 2 powerhouses by diverting water from the Middle Fork Rogue River and Red Blanket Creek into the Rogue River at the North Fork diversion dam, thereby regulating fluctuations in downstream flows.
Prospect No. 3, conveying water from the South Fork to the Middle Fork canal via a newpowerhouse, came online in 1933, with Prospect No. 4 in 1944.
|Spill from North Fork Reservoir sends water to the powerhouses at Prospect Nos. 1, 2, and 4.|
Prospect No. 1 a power player
After 52 years of operation, the 3.75-MW generator installed during construction of Prospect No. 1 construction failed in 1964 and was considered a total loss. The discussion that followed highlights the important role of the Prospect facilities in the local and regional power grid.
In a 1961 merger, COPCO became Pacific Power and Light, now known as PacifiCorp. The acquisition of properties in the merger included hydro plants on the Rogue, Klamath and Umpqua rivers, as well as nearly 100,000 local customers.
As the new owner of the Prospect Diversion Project, Pacific Power identified four options: abandon the plant, replace the generator, rebuild the plant completely, or add a third unit at Prospect No. 2 to capture energy from water that otherwise would have been diverted to the Prospect No. 1 hydro plant.
Company officials reviewed the options and determined regional energy demands would not justify the expansion of Prospect No. 2 until about 1980, and abandonment of Prospect No. 1 would mean purchasing power on the market. Most importantly, they determined that investment in a new Prospect No. 1 generator could be quickly recouped in the existing market.
They ultimately chose this option to place Prospect No. 1 back into service as quickly as possible. While the other powerhouses continued operation, a new turbine and generator were installed. The powerhouse contains an Allis Chalmers horizontal Francis turbine, rated 7,000 hp under a net head of 525 feet, which drives a General Electric generator with a capacity of 4.7 MW and power factor of 0.8. Total capacity is 3.75 MW.
Preparing for the next 100 years
Today, more improvement initiatives are under way, as required by the project’s FERC license. “We are now in early stages of implementing measures for better control of the facilities that provide for higher minimum flow in the bypass reaches and to control ramping so river fluctuations do not impact fish,” Garrett says. “We’re also providing crossings on the canals for big game and other wildlife – 12-foot-wide concrete slabs covered with earth and other material to look like natural walkways. We’re building 10 of those, as well as 72 2-foot-wide crossings for squirrels, mice and other small wildlife.
“Prospect is a mouse-friendly facility,” he says with a laugh.
The company has also made significant improvements to North Fork Park, a recreational site with picnic tables and access to North Fork Reservoir. Scheduled releases of water from the reservoir provide opportunities for whitewater recreation four days each year. And through a separate agreement with the Oregon Department of Fish and Wildlife, PacifiCorp has provided funding for habitat enhancement projects that benefit fish and wildlife.
“It’s an honor to have Prospect inducted into the Hydro Hall of Fame and recognized for its significance in history and investments for the future,” says Will Shallenberger, hydro engineering director, who accepted the award from the editors of Hydro Review during a ceremony at the 2012 HydroVision International event.
“Over the years, dedicated employees have worked hard to create and maintain a reliable and efficient system of generating electricity for customers, while keeping our environmental impact at a minimum,” he says. “As we celebrate the historic accomplishment of 100 years of power generation, we’re also planning for the future to allow us to continue producing clean energy for generations to come.”
Tom Gauntt is spokesman for PacifiCorp.