GreenTown Los Altos

Permanente Creek: The Future Looks Bright


Jul 2013


On May 4, 2013, 60 lucky participants boarded a Google Bus and toured Permanente Creek from Rancho San Antonio to the Bay. Sponsored by the Committee for Green Foothills and GreenTown Los Altos, speakers talked about flood control to fish passage, from history to future and from climate change to creek dynamics.

In the early 1800s, the Spanish settlers took notice of a significant steelhead trout creek with perennial flow, and they named it Arroyo Permanente. The headwaters in limestone-rich Black Mountain release their winter rains slowly through the year into the creek.

Fast forward to 2013, this creek has changed substantially.

The pristine headwaters still contain descendants of steelhead trout, but they are landlocked by manmade barriers. Lehigh Cement and Quarry occupy 3.5 miles of creek and for the last 70 years, the water flow has been dammed, diverted, filled with sediment and poisoned with selenium and mercury.

Following the flow below Lehigh, the creek enters Rancho San Antonio Creek. This is the only accessible section of creek that bears some resemblance to its original form. Downstream of RSA the creek flows through residential area, Heritage Oaks Park and then a diversion channel. In 1959, Santa Clara Valley Water District built a trapezoidal channel to divert Permanente’s flow to Stevens Creek. The water flow beyond the channel’s location at Portland & Miramonte out to the bay was considered only a flood risk and not needed for any creek life. Although Stevens Creek does have steelhead trout, the fish have no chance of entering the diversion channel or swimming the 1.3 miles of channel.

Despite the ignorance and abuses of the past, Permanente’s future is bright, especially for steelhead trout. On Earth Day 2013, Sierra Club and Lehigh signed a consent decree requiring restoration of the section of Permanente that runs through Lehigh and calls for a water treatment plant. Lehigh’s section of creek will be fish habitable by 2015.

Once the Lehigh section of the creek is ready for steelhead trout, the remaining barrier is the diversion channel. A group of concerned citizens and environmentalist are investigating options diversion channel. The Water District estimates $12M to make the channel suitable for fish migration.

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