Wild & Scenic Mokelumne Update

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Conservancy partners with local contractors to remove obsolete local dam
East Panther Creek Diversion structure after dam removal
On November 3, 2016, Foothill Conservancy made a literal bang when we successfully blew up an old, obsolete Pacific Gas and Electric Company diversion dam on East Panther Creek. The creek flows from just below Highway 88 east of Pioneer to its confluence with West Panther Creek, then to the beautiful, Wild and Scenic River-eligible North Fork Mokelumne River upstream of Tiger Creek Powerhouse. With the dam blasted and removed, the creek again flows freely from its headwaters to the North Fork.

The dam removal was a long time coming, and we were very excited to see it finally happen. The project resulted from our committed participation in the Mokelumne River Project 137 Ecological Resources Committee, which has overseen the adaptive management program for PG&E’s Mokelumne River hydroelectric project since 2001. The committee oversees the monitoring program that measures the effects of PG&E’s project, which extends from Blue Lakes in Alpine County to the Electra Powerhouse near Jackson. The committee adjusts stream flows and management based on the monitoring results.

“It took a lot longer than six years, but we were finally able to convince the state to honor its commitment to funding the final removal of the dam” said Bell. “Seeing this project finally come about was really satisfying.”

Hard work and persistence pay off

Built in the 1930s, the East Panther Creek Dam was originally constructed to divert water to the Tiger Creek Conduit, the large, concrete flume that runs from Salt Springs Reservoir to the Tiger Creek Powerhouse. The diversion dam was operated only during dry years when less water was available to divert from the North Fork Mokelumne. The dam silted up in 1996 and hadn’t been used since. In 1999 nonprofit organizations, federal agencies, state agencies and PG&E came together to negotiate a settlement agreement that led to the issuance of PG&E’s federal Mokelumne hydropower license. During these discussions, the parties identified dams on three North Fork Mokelumne tributaries, Beaver Creek, West Panther Creek, and East Panther Creek, as having limited value for hydropower generation, but high biological value. Popular with anglers, the creeks are home to native rainbow trout as well as salamanders and other aquatic life.

During the license negotiations, PG&E proposed to dredge the sediment from behind the dams and resume their operation. But our Vice-President Pete Bell and other parties, including the California Department of Fish and Game (now Wildlife), argued that since the dams were only used in dry years when the creeks most needed water, and they blocked fish passage, it would make more sense to remove them. Eventually, all parties to the agreement, including PG&E, agreed to dismantle, breach and remove the dams.

PG&E agreed to pay for the breaching of the two Panther dams and the dismantling of the Beaver diversion structure. State wildlife officials agreed to pay for the removal of the remnants of the Panther dams if the group could not find funding within six years after breaching them.

In 2003, PG&E breached East Panther Creek Dam, dismantled the diversion structure on Beaver Creek, and breached and completely removed West Panther Creek Dam. Unfortunately, the remaining parts of East Panther Creek Dam redirected stream flows in a way that created erosion problems immediately downstream.

It was clear that the rest of the dam needed to come out. But the state postponed funding for the project during the Recession and for years afterward. Our own efforts to secure state funding from other sources didn’t succeed because the state was legally obligated to remove the dam. So along with our Project 137 committee partners, we persisted in pushing the Department of Fish and Wildlife to honor its obligations under the license settlement agreement.

Local contractors carry out state-funded removal

In 2015, the state agreed to pay to finally remove what remained of the dam. In fall 2016, we executed a state grant agreement and hired two, state-selected local contracting firms to complete the demolition. The work was scheduled for the end of the fall season when the creek would be at its lowest annual flow so that the demolition would be least likely to harm water quality and the stream ecology.

California Drilling and Blasting of Copperopolis took on the explosives work to blow up the dam. Campbell Construction of Sutter Creek was responsible for debris removal. After the initial explosion, one portion of the dam’s diversion structure remained standing since it was more-resistant to the force of 176 pounds of dynamite than the original, older dam. After a second blast, a portion of the structure still remained.

After consulting with the contractors and project partners, we determined that a heavy-duty rock hammer attached to an excavator was needed to remove the rest of the structure. That work was delayed due to rain and snowstorms that increased the risk of operating heavy equipment in higher stream flows. So, we shifted our emphasis to cleaning up most the debris. Campbell Construction will complete the final demolition and removal of the last piece of the diversion structure next fall.

We were able to film the explosion, thanks to the loan of a Go-Pro camera from our supporters Kylee and Scot Campbell. Our Watershed Conservation Associate Reuben Childress used that footage and other resources to create an informative short film about the dam removal. You can view the resulting YouTube video on our homepage.

Thanks to our partners and contractors

The confluence of Panther Creek and the North Fork Mokelumne River is one of the most wild and gorgeous sections of the watershed. We would like to thank all our members who have continuously supported our work to protect special places like this one. We would also like to thank the California Department of Fish and Wildlife, PG&E, the U.S. Forest Service, Campbell Construction, and California Drilling and Blasting for helping to complete this project.

If you would like to learn more about dam removals and access to the creek or this section of the Mokelumne River, or you have any questions about this dam removal project, please e-mail Reuben Childress or give him a call at: 209-223-3508.

THE FOOTHILL CONSERVANCY  |  35 Court Street, Suite 1   Jackson, CA  95642  |  209-223-3508