LIHI Certificate #114 - Mahoning Creek Project, Pennsylvania

The Mahoning Creek Project is located on Mahoning Creek in Armstrong County, Pennsylvania. The existing Mahoning dam and reservoir were constructed by the US Army Corps of Engineers (USACE) beginning in 1939 and became operational in 1941. The dam was designed with two conduits built into the south abutment of the dam for future hydropower development. Construction of the hydro project began in March 2013 and the facility began commercial operations in December 2013. Authorized by Congress through the Flood Control Acts of 1936 and 1938, it is one of 16 flood control projects in the USACE Pittsburgh District used to provide flood protection to the lower Allegheny River Valley and the upper Ohio River.

The project includes a 162-foot-high, 926-foot-long dam with a 192-foot-long spillway section; five 29-foot-high, 30-foot-long vertical lift gates (i.e., sluice gates); a 192-foot-wide, 950-foot-long stilling basin regulated by a 180-foot-long flat-crested stilling basin weir and located downstream of the dam; a 50-foot-high intake structure attached to the upstream face of the dam; a 1,090-foot-long, 10-foot-diameter penstock; and a powerhouse containing two vertical-shaft generating units with a total installed capacity of 6 MW.

The project operates in modified run-of-river mode and impounds a 280-acre reservoir. USACE operates the dam to augment flow during dry periods to maintain downstream water quality and as water supply for domestic, industrial, and recreational uses. The USACE maintains the summer pool level and during the fall, the pool level is lowered to provide flood storage capacity. An Adaptive Management Plan (AMP) with USACE dictates the minimum flows released through the USACE bypass. Depending on the time of year the minimum discharge ranges from 30 cfs – 60 cfs to ensure that existing water quality conditions are maintained.

Water quality impacts are controlled by the AMP which defines requirements for dissolved oxygen, temperature, and total dissolved gas; all beyond state water quality standard requirements. The project owner works closely with USACE, FERC, Pennsylvania Department of Environmental Protection, and state and local authorities to ensure that the project maintains existing water quality conditions throughout construction and during operation of the Project.

Project Name Mahoning Creek
LIHI Certificate No. 114
LIHI Certificate Term November 14, 2018 - November 13, 2028
Owner Mahoning Creek Hydroelectric Company
State Pennsylvania
Location Located on Mahoning Creek in Armstrong County, Pennsylvania. The dam is 21.6 miles upstream from the junction of the creek and the Allegheny River.
Installed Capacity 6.0 MW
Average Annual Generation 18,500 MWh
Facility Type Modified run-of-river
FERC No. P-12555 issued 2011, expires 2061

PLUS-Standard: The project operates under an adaptive management program and regularly evaluates the operation of the facility with respect to enhancing water quality.

Mahoning Creek historically has not supported migratory fish and there are no anadromous or catadromous fish present. USACE and the Pennsylvania Fish and Boat Commission have conducted fish studies documenting 39 fish species, none of which are anadromous or catadromous. Trashracks with 1-inch spacing and 1 foot per second approach velocity mitigates entrainment.

The project property comprises roughly 10 acres. The project requires a wetland protection plan that details avoidance and protection measures for wetlands in the vicinity of the project’s construction activities. Erosion control and restoration measures are included in the plan, as well as wooded area preservation along the entire length of the project. The rest of the shoreline is controlled by USACE. No threatened or endangered species, or their habitats, exist in the project area.

The project has implemented a Programmatic Agreement between FERC and the State Historic Preservation Officer (SHPO) which required the development of a Historic Properties Management Plan. The plan provides guidance for the consideration, management, and protection of known and any newly discovered historic properties during construction, operation, and maintenance of the project. The project reports annually to FERC and the SHPO summarizing ground-disturbing activities.

PLUS-Standard: The project provides tours of the facility and hosts a Summer Internship Program for students from Pennsylvania State University, one of the project’s purchasers of the energy generated. The internship program provides an opportunity for students to learn about energy project management, environmental monitoring, cultural/historic resource compliance; all in a real-world environment.

Recreational resources at the project include an Americans with Disabilities Act compliant fishing access point and interpretative signage. Public access is provided free of charge.


Certification History

November 7, 2019: The decision to recertify the Mahoning Creek project is final. No appeal requests were received during the appeals period that closed November 2, 2019. The project is recertified with a term from November 14, 2018 – November 13, 2028. The Certification includes two conditions:

  • Condition 1: The facility Owner shall continue to cooperate and participate in any new studies of ecological flow requirements at the Project and provide copies of any study reports and related consultation to LIHI in annual compliance statements.
  • Condition 2: The facility Owner shall continue to work with USACE to investigate possible flexibility in the existing Water Control Manual to keep short-term dam releases at higher, more stable minimum levels. If such flexibility can be agreed to between USACE and the Owner, the Owner shall implement improved minimum releases.

October 3, 2019: The Low Impact Hydropower Institute has preliminarily approved Low Impact Recertification for the Mahoning Creek Hydroelectric Project, LIHI #114.

This decision is preliminary pending the 30-day appeal window. Only those who commented on the initial application during the 60-day comment period are eligible to file an appeal. Such appeal needs to include an explanation as to how the Project does not meet the LIHI criteria. Appeal requests can be submitted by email to comments@lowimpacthydro.org with “Mahoning Creek Hydroelectric Project” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Ave, Suite 6, Lexington, MA 02420. All requests will be posted to the website.  The applicant will have an opportunity to respond and any response will also be posted. Requests must be received by 5 pm Eastern time on November 2, 2019.  The full application and reviewers report are available below.

If no appeal requests are received and the decision becomes final, the Certification term for the Project will be November 14, 2018 for a term of ten (10) years, which will expire on November 13, 2028.

July 31, 2019: The Low Impact Hydropower Institute has received a complete application for Low Impact Recertification of the Mahoning Creek Hydroelectric Project.  LIHI is seeking public comment on this application.  Specifically, we are interested in knowing whether you think the Project meets the LIHI Low Impact Certification Criteria, as revised in the 2nd Edition Handbook.  Please review the program and criteria in LIHI’s revised Handbook and then review the Project’s application materials below.

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 comments@lowimpacthydro.org with “Mahoning Creek se Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Avenue, Suite 6, Lexington, MA 02420.  Comments must be received on or before 5 pm Eastern time on September 29, 2019 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.

June 18, 2014: The Mahoning Creek Project is certified as low impact for a five-year term, effective November 14, 2013 and expiring November 14, 2018.

January 13, 2014: Public comment period has closed.

November 14, 2013: Mahoning Creek Hydroelectric Company submitted an application for certification of the Mahoning Creek project; application posted to website and public comment period opened.


Files:

2019 Recertification

2014 Certification