SCE mobilization of heavy equipment at gem lake dam

Skycranes were in short supply during last year’s wildfire season

BISHOP, CA April 5, 2021— The Inyo National Forest recently approved helicopter use for Southern California Edison’s (SCE) Gem Lake Dam valve replacement project, which will resume in April.  SCE operates the Gem Lake Dam as part of the Federal Energy Regulatory Commission Hydroelectric Project #1388.  Gem Lake is located west of the June Lake Loop area and the aging and deteriorating infrastructure make the project a priority for SCE.

The valve replacement project was initiated last summer but not completed due to the unavailability of heavy lift helicopters.  These type of helicopters—frequently referred to as “Skycranes”—were unavailable for much of the construction season due to being committed to wildland firefighting efforts.

SCE 2019 gem lake valve

SCE 2019 Gem Lake Valve

With the summer fast approaching and the same limiting factors of heavy lift helicopters being a challenge again, as well as spring snow conditions precluding access via the Rush Creek trail, the Inyo National Forest authorized SCE to transport personnel and equipment to Hat Ridge.  For this phase of the project, a combination of medium and heavy lift helicopters will be used to support the operation.  Between April 27 and May 14, a total of 188 flights will occur from the staging area at the June Mountain Ski Area parking lot to Hat Ridge, which is located just below the Gem Lake Dam outside of Congressionally-designated Wilderness.  The high number of flights is necessary because of the limited number of personnel permitted on each flight due to COVID safety mitigations. Ten of the 188 flights will be accomplished with heavy lift helicopters and will occur on May 7 and 8 to complete the final valve replacement.  All flights will take place from 7 a.m. to sunset, seven days a week. A map of the work area and helicopter flight paths is on our website at:

SCE short pipe section was placed with mini excavator gem lake dam

SCE work on Gem Lake Dam included a short pipe section that was placed with a mini excavator


Residents and visitors can expect to frequently hear and see helicopters during this operation.  Both SCE and the Inyo National Forest appreciate the public’s understanding and patience while this critical infrastructure project is completed.  By conducting this work prior to the start of the summer season, SCE will be able to complete the project this year while minimizing conflicts during the peak recreation season.

For questions or concerns about this project, please contact Lands Specialist Sheila Irons at (760) 965-9609 or [email protected].

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