On March 4th 2011, the Federal Energy Regulatory Commission (FERC) issued an order granting an original license to construct, operate and maintain the proposed 6.0 MW Mahoning Creek Hydro Electric Project (Project) No. 12555 to the Mahoning Creek Hydroelectric Company, LLC. The Project is built at the existing Mahoning dam and includes 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 a 4-MW and a 2-MW vertical-shaft generating unit. Construction of the project began in March 2013 and the facility began commercial operations in December 2013.
|Project Name||Mahoning Creek|
|LIHI Certificate Number||114|
|LIHI Effective and Expiration Dates||November 14, 2013
November 14, 2018(extended to September 30, 2019)
|Owner||Mahoning Creek Hydroelectric Company|
|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|
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. The USACE project consists of: a 162-foot-high, 926-foot-long dam with 192-foot-long spillway section equipped with five 29-foot-high, 30-foot-long vertical lift gates (i.e., sluice gates), impounding a 5-mile-long, 280-acre reservoir with a normal pool elevation of 1,077 feet mean sea level (msl); and 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. The Mahoning dam is located on Mahoning Creek in Armstrong County, Pennsylvania. The dam is located 21.6 miles upstream from the junction of the creek and the Allegheny River. 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.
USACE operates the dam in a modified run-of-river mode 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 elevation at 1,100 feet msl ± 0.5 foot, and during the fall, the pool level is lowered to elevation 1,075 feet msl 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.
Currently, the dam’s primary use is for flood control and storm water management; however, the dam and the area surrounding it are often used for recreational activities, such as boating, fishing, hiking, hunting, trapping, and picnicking. The hydroelectric Project generates clean, carbon-free electricity in accordance with the current dam operation established by USACE. Therefore, the Project has no negative impact on the current uses of the dam, the planned uses of the dam, or the surrounding and downstream environment. The Mahoning Creek team worked closely with USACE, FERC, Pennsylvania Department of Environmental Protection, and state and local authorities to ensure that the Mahoning Creek Project maintained existing water quality conditions throughout construction and during operation of the Project.
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.
- MahoningCreek – Final Review Report 5-12-2014
- LIHI Final Questionnaire – Mahoning Creek Hydroelectric Project
- Description of Facility – Introduction
- Description of Facility – Project Maps
- Summary of Major Licenses and Permits
- Access Memorandum Of Agreement
- CWA Section 401 Permit – PA DEP
- CWA Section 404 Permit – Army Corps
- FERC Original License – Status Update to LIHI
- FERC Original License (2011)
- Limited Power Permit
- NPDES Permit
- Rivers and Harbors Act Section 408 Permit
- Submerged Lands License Agreement
- Contacts at Resource Agencies Operations Plan (with water flow information)
- A – Response Narrative for Flows A – Adaptive Management Plan Part l
- A – Adaptive Management Plan Part 2
- A – Adaptive Management Plan Part 3
- A – Article 307 from FERC License
- B – Response Narrative for Water Quality
- B – 401 Water Quality Certification
- B – Water Quality Report (October 2007)
- C – Response Narrative for Fish Passage and Protection
- C – FERC Full Notice to Proceed (May 8, 2013)
- C – FERC Notice to Proceed on Intake Construction (March 12, 2013)
- C – Intake Structure Design Plan Requirement (excerpt from FERC License)
- C – Intake Structure Design Plan (part 1)
- C – Intake Structure Design Plan (part 2)
- C – FERC Environmental Assessment
- D – Response Narrative for Watershed Protection
- E – Response Narrative for Threatened and Endangered Species Protection
- E – PNDI Search and Letters
- E – Threatened and Endangered Species (excerpt from FERC License)
- F – Response Narrative for Cultural Resource Protection
- F – Historic Properties Management Plan (HPMP), as part of approved FERC License
- G – Response Narrative for Recreation
- G – Recreation and Aesthetics Plan
- H – Response Narrative for Facilities Recommended for Removal