LIHI Certificate #131 – Chester Diversion Project, Idaho

The Chester Diversion facilities are owned and operated by Fall River (Licensee), while the Project dam is owned by the Freemont Madison Irrigation District. The Chester Diversion Dam (also known as the Cross Cut Diversion Dam) and associated Cross Cut Irrigation Canal were constructed in 1938 by the U.S. Department of the Interior, Bureau of Reclamation (BuRec) as part of its Minidoka Project. On September 10, 2004, the BuRec transferred, by quitclaim deed, the title to the Chester Diversion Dam, portions of the Cross Cut Irrigation Canal, and related tracts of land to the Fremont-Madison Irrigation District. The ownership, operation, and maintenance of the dam, irrigation canal, and related lands are entirely under nonfederal control. Under a November 16, 2007 MOU established between the Licensee and Fremont Madison Irrigation District, Fall River is allowed to utilize the Chester Diversion Dam for the purposes of producing hydroelectric generation. Fall River is responsible for paying all costs associated with the engineering, construction, operation and maintenance of the hydroelectric project.

On July 23, 2008 the Federal Energy Regulatory Commission (FERC) issued a 40-year license for the Project. The 2008 FERC license incorporates measures stipulated within a November 9, 2007 Settlement Agreement established between the Licensee and U.S. Department of Agriculture – Forest Service (USFS), U.S. Department of Interior – Fish and Wildlife Service (USFWS), Idaho Department of Fish and Game (IDFG), Idaho Department of Parks and Recreation (IDPR), Trout Unlimited (TU), the Henry’s Fork Foundation, and the Greater Yellowstone Coalition. The purpose of the Settlement Agreement was to resolve among the signatories all issues regarding fish, wildlife, recreational, and aesthetic resources associated with issuance of the original Project License.

Prior to the construction of the hydroelectric facility, the existing Chester Diversion Dam facility consisted of a concrete gravity dam, one radial gate on the south end of the diversion structure to control flows into the Cross Cut Irrigation Canal and an additional smaller radial gate on the north side of the diversion structure to control flows into the Last Chance Irrigation Canal. Construction of the hydroelectric facility components (inflatable rubber dam, concrete intake structure, sluiceway/logway, fish screens, headworks for irrigation canals, powerhouse, and transmission lines) began in 2009 and were completed in 2014.

As described under the 2008 FERC License the Chester Diversion Hydroelectric Project consists of: 1) the Fremont Madison Irrigation District owned concrete dam with a crest length of 355 feet and a structural height of 17 feet; 2) a 38 inch-high inflatable rubber dam bolted to the crest of the dam, that, when inflated, creates a reservoir with a water surface elevation of 5,043.7 feet msl; 3) a 355 foot-long overflow spillway with a crest elevation of 5,040.5 feet msl; 4) a flow control structure located on the south side of the dam, with a radial gate that controls flows into the Cross Cut Irrigation Canal; 5) a flow control structure located on the north side of the dam with a radial gate that controls flows into the Last Chance Irrigation Canal; 6) a 50 foot-wide concrete intake structure on the south side of the spillway; 7) a sluiceway/logway adjacent to the intake structure on the south end of the spillway; 8) a 1.5 inch-spaced fish screen across the turbine intake and 0.25 inch-spaced fish screens across the entrances to both irrigation canals; 9) Cross Cut Irrigation Canal headworks; 10) Last Chance Irrigation Canal headworks; 11) 50 foot by 50 foot concrete powerhouse with three Kaplan-type turbine generator units with a combined capacity of 3.3 MW; 12) concrete wall located immediately below the powerhouse that directs flow to the center of the Henry’s Fork; 13) a 15-Kilovolt primary transmission line; and 14) appurtenant facilities. The project boundary incorporates the Chester Diversion Dam topped with the rubber dam, Chester Diversion Dam reservoir, lands associated with canal headworks, powerhouse, parking lot, upstream and downstream boat launches, and the primary transmission line.

The Project operates in a run-of-river mode. After irrigation needs are met, up to 3,500 cubic-feet per second (cfs) are diverted into the powerhouse for generation. Any flows greater than both irrigation and power needs spill over the Chester Diversion Dam. The Licensee provides a minimum flow of 25 cfs through the sluiceway/logway to allow for downstream fish passage.

Project Name Chester Diversion
LIHI Certificate No. 131
LIHI Certificate Term October 17, 2016 - October 17, 2024
Owner Fall River Rural Electric Cooperative
State Idaho
Location River mile 38.5 on the Henry’s Fork of the Snake River in Fremont County
Installed Capacity 3.3 MW
Average Annual Generation 16,800 MWh
Facility Type Run of River
FERC No. P-11879 issued 2008, expires 2048

Certification History

January 20, 2017: LIHI Executive Director, Shannon Ames, using authority delegated from the LIHI Governing Board, has issued a Preliminary Certification Decision that the Chester Diversion Hydroelectric Project (FERC No. P-11879) satisfies the LIHI Certification Criteria. The Chester Diversion project also qualifies for one PLUS standard due to its endangered species management efforts, earning an additional three years on the certification term.  The certification includes one facility-specific condition, as follows:

  • Condition 1.  the facility owner shall adhere to the timelines, monitoring, and study scopes for all aspects within the Trout Monitoring Plan related to restoration of Yellowstone cutthroat trout. In its annual compliance statement to LIHI, the facility owner shall summarize prior years’ progress with regard to the plan.  If any changes are made in that plan, LIHI shall be notified within 30 days of the finalization of such changes.

As provided for in Section 4.2.5 of the LIHI 2nd Edition Handbook, the Preliminary Certification Decision, along with the Application Reviewer’s report and (if prepared) report of the Executive Director, will be posted on the Institute’s Web page for 30 days.  Notice of the posting will be provided to all individuals or organizations that commented on the initial Application Package.

Any Commenter may submit a letter to the Executive Director requesting an appeal within the 30-day period.  The appeal request must state specific reasons why the hydropower facility should have failed one or more criteria.  Only individuals or organizations that commented on the initial Application Package may file an appeal.

If no appeal is requested within the 30-day period, the Executive Director will issue LIHI Certification for the facility and post a notification of certification on the Institute’s website.  Once final, the effective certification date for the Chester Diversion Project is October 17, 2016 for an eight (8) year term, which will expire on October 17, 2024.

October 20, 2016: On October 17, 2016, the Low Impact Hydropower Institute (LIHI) received a complete application from the Fall River Rural Electric Cooperative (Fall River), for the Low Impact Certification of the Chester Diversion hydroelectric project (FERC No. 11879), located on the Henry’s Fork of the Snake River in Fremont County, Idaho.

LIHI is seeking public comment on this application. Specifically, we are interested in knowing whether you think the Chester Diversion project meets the LIHI Low Impact Certification Criteria. The Chester Diversion application is subject to review using the Criteria in the 2nd Edition Certification Handbook of March, 2016.  Please review the program and criteria in LIHI’s 2016 Handbook and then review the Project’s 2016 application materials posted on the project page. Comments that are directly tied to specific LIHI criteria (flows, water quality, fish passage, etc.) will be most helpful, but all comments will be considered. Comments may be submitted to the Institute by e-mail at with “Chester Diversion Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, PO Box 194, Harrington Park, New Jersey 07640. The 60 day public comment period begins on October 20, 2016.  Comments must be received at the Institute on or before 5 pm Eastern time on December 19, 2016 to be considered. All comments will be posted to the web site and the applicant will have an opportunity to respond.  Any response will also be posted.