Wild & Scenic Mokelumne Update

Foothill Focus Newsletter
photo of Mokelumne River
North Fork Mokelumne River below Salt Springs Dam
Foothill Focus Winter 2007 (January)
West Panther Creek coming back after dam removal
On Saturday, October 28, volunteers from the Conservancy, Earth Team, and U.S. Forest Service spent the day on West Panther Creek monitoring changes in the creek channel where a Pacific Gas and Electric Company dam was removed in 2003. West Panther Creek is a tributary of the North Fork of the Mokelumne River.

“Removing the dam on West Panther allowed fish to swim up and down the creek for the first time in 68 years,” said Pete Bell, Foothill Conservancy Vice President. “It also gave us a rare opportunity to see, in our own back yard, how formerly dammed Sierra streams recover over time.”

The West Panther Creek dam was fully silted up at the time of its removal. As part of the removal project, PG&E heavy equipment operators worked under the direction of U.S. Forest Service hydrologist Cheryl Mulder to carve a new stream channel in the sediment upstream of the dam. The annual volunteer monitoring collects data on how the stream has changed since then. This was the third annual monitoring event.

“The big storms last year were the heaviest in many years” said Mulder, “and they produced a flood that hasn’t been experienced in 85 years in this watershed. The changes from last year to this are amazing. The creek has definitely reclaimed its channel. It looks like up to 90 percent of the sediment that had backed up behind the dam has been transported downstream. This sediment will provide gravels for downstream fish spawning habitat in West Panther Creek and the North Fork of the Mokelumne River.”

“We haven’t had the scientific resources to conduct a full study that would include biological and physical effects of the dam removal.” Bell said. “And while U.C. Davis scientists were very interested, their plates were too full to take it on. Still, we hope the data we have collected, and Cheryl’s analysis of it, will help scientists learn more about bedrock-influenced, gravel bed Sierra streams.

“We sure saw dramatic changes this year,” said Bell. “And we had some surprises, too. We found a large concrete structure in the streambed that previously was buried under sediment. We’ll be talking to PG&E about whether and how to get that removed.”

This year’s volunteer team used several data collection methods. Conservancy President Katherine Evatt took photos of the full study reach and from each of seven established cross-sections, called “transects,” analyzed each year. Bell and Mulder measured the active stream channel and full width of each transect.

Earth Team members Gwen Starrett and Jason McCleery of rural Plymouth conducted the annual “pebble count,” wading in the cold water and measuring rocks on the creek bottom. Starrett, an aquatic ecologist who teaches third grade at Ione Elementary, noted there were “great bugs” in the creek, too: caddis flies, stoneflies, and mayflies—three groups of insects that indicate good water quality and habitat.

“We expect the channel to become more stabilized in the future,” said Mulder, “We hope to see the banks taking a more natural slope with more vegetation over time, and the stream channel forming more of a natural step-pool structure as the rocks move in the winter storms.”

Bell, Forest Service fisheries biologist Jann Williams, Conservancy Executive Director Chris Wright, and reporter Dana Nicholls of The Record returned later in the fall to complete this year’s monitoring. They spent another day in the icy creek with a laser level taking profile measurements of the full study segment and transects.

The 2003 West Panther dam removal was brought about by a collaborative relicensing settlement agreement among PG&E and nine parties, including the Foothill Conservancy, which led to PG&E’s current 30-year license for its Mokelumne River hydroelectric project. It was the first modern dam removal by PG&E in the company’s history.

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