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Established in 1918, the Central Oregon Irrigation District (“COID”) is a Municipal Corporation of the State of Oregon. The system consists of two main canals: the Pilot Butte Canal, which runs north, through Bend, Redmond and Terrebonne; and the Central Oregon Canal, which runs east, through Bend, Alfalfa and Powell Butte. Both canals divert water from the Deschutes River. The District provides water for about 45,000 acres within an 180,000 acre area in Central Oregon. More than 700 miles of canals provide agricultural and industrial water to the Terrebonne, Redmond, Bend, Alfalfa and Powell Butte areas. In addition, COID provides water to the City of Redmond and numerous subdivisions; in Bend, many parks and schools receive water through the COID system.

Project Name Siphon Power
LIHI Certificate Number 73
LIHI Effective and Expiration Dates October 28, 2015
October 28, 2020
Owner Central Oregon Irrigation District
State Oregon
Location Located on the Deschutes River, Oregon.
Installed Capacity 5.5 MW
Average Annual Generation 22.55 GWh
Facility Type
FERC No. 3571

The Central Oregon Irrigation District owns and operates a hydropower plant on a diversion from the Deschutes River in Bend, Oregon. Water for the Central Oregon Canal is diverted from the Deschutes River about three miles upstream from Bend’s Colorado Street Bridge. Near the diversion site, the river is in a steep, narrow canyon. About a mile and a quarter downstream from this diversion structure, COID has built an underground powerhouse containing two generators and turbines. At a point above the powerhouse, the canal is 135 feet above the river. Here the water is diverted into a buried pipe that brings it into the powerhouse.  At the powerhouse, the water enters one of the two turbines to produce electricity before being returned to the Deschutes River. The energy produced travels through an underground power line to a transformer located near the canal and then into the existing power grid. Pacific Power & Light has agreed to buy all the power COID will generate during the next 35 years.  The Oregon Department of Energy provided the financing for the project in the form of revenue bonds, which will be repaid by the project. Profits will then be used to (1) control or reduce assessments levied upon its water users for District operation and maintenance, (2) to launch the first large water conservation program in Central Oregon and (3) to make capital improvements for the District.

The facility consists of the use of the pre-existing Central Oregon Irrigation District’s Central Oregon Canal system including the Deschutes River diversion and the downstream approximately two miles of water conveyance system to deliver water to the facility penstock and powerhouse. The diversion and water conveyance were constructed in the early 1900’s and utilized an on grade wood flume to transport the irrigation water out of the steep river canyon where the water entered an open canal to deliver irrigation water to lands north and east of Bend. The wood flume was replaced in the early 1970’s with a ten foot diameter steel pipe in a double inverted siphon configuration to transport the irrigation water from the diversion to the open canal. The siphon pipe was designed for a flow of about 800 cubic feet per second which is more than the irrigation demand most of the time.

In the early 1980’s the site was identified as a potential small hydro site and in 1982 the district applied for a FERC License that was issued in 1987. The existing diversion consisted of a diversion structure with two control gates to regulate the amount of water diverted. The diversion that was modified in 1970 featured a louver array to guide fish entering the diversion to a return facility to move the fish back into the river. The amount of water diverted for power generation varies from a minimum of about 80 cfs up to about 640 cfs and is dependant on the capacity of the siphon pipe in excess of the irrigation demand and the minimum streamflow requirement of 400 cfs between the diversion and the point of returning flow to the river at the powerhouse. The water available for power generation depends on irrigation flow releases from upstream storage reservoirs during the irrigation season and typically the flow in the bypassed reach is much more than the minimum 400 cfs. During the non irrigation season, flow available will range from none to the maximum generation capacity of about 640 cfs.

Downstream of the fish protection facility, the water enters the 10 foot diameter double inverted siphon pipe. About 1200 feet downstream of the start of the open canal, a buried 9 foot diameter pipe is utilized to deliver excess water to the power facility about 800 lineal feet from the canal where the water enters the turbines and is delivered back into the river.

The power generated is transported underground for about 800 feet to a small project substation located out of sight from the river where it is stepped up from 4160 volts to a nominal 69,000 volts where it is delivered to the power purchaser.

COID 1

Pipe installation in snow 1

Certification History

April 20, 2016: LIHI Executive Director Michael J. Sale, using authority delegated from the LIHI Governing Board, has certified that the Siphon Power Hydroelectric Project (FERC No. P-3571) satisfies the LIHI Certification Criteria.  A Preliminary Decision was announced on March 4, 2016, and a 30-day appeal period was open through April 4, 2016. No requests for appeal were received. This Certification Decision includes two facility-specific conditions, as follows:

  • Condition 1.  As part of their annual Compliance statement to LIHI, the Owner shall include electronic copies of or electronic addresses to the reports that they file with the Oregon Department of Fish and Wildlife related to conservation flows and tailrace fish observations, covering the prior four quarters.
  • Condition 2.  The Owner shall notify LIHI within 30 days of any changes in the level of mitigation enhancement funding for fish and wildlife, with particular attention to changes at or around January 1, 2021.

The effective certification date for the Siphon Power Project is October 28, 2015 for a five (5) year term, which will expire on October 28, 2020.

November 2, 2015: The Low Impact Hydropower Institute has received a complete application for a new term of Low Impact Certification for the Siphon Power Hydroelectric project.  The application materials can be found in the Files section below.

The public comment period for this application closed on December 30, 2015.

June 19, 2015: The Siphon Power Hydroelectric project has been granted an extension of the current certificate term. The new expiration date is December 31, 2015. See ExtensionLetter_2015Recert for explanation below.

May 28, 2011: The Siphon Power Hydroelectric Project has been certified as low impact for a five year term, effective October 28, 2010 and expiring October 28, 2015.

October 28, 2010: The Central Oregon Irrigation District has submitted an application for certification of the Siphon Power Project.


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