Restoring the Northern Watershed

The headwaters of the Arroyo Mocho tributary of Arroyo de la Laguna, through the Mocho Gorge along Mines Road, has been identified as potential suitable spawning and rearing habitat for steelhead trout. Arroyo Mocho was a historic migration route and habitat for steelhead trout. Many small potential fish passage barriers have been identified in Arroyo Mocho between Arroyo las Positas in Pleasanton and the Mocho Gorge. The Alameda Creek Alliance has been lobbying for fish passage at these barriers and connection of the Mocho Gorge habitat with the Bay.

The Alameda Creek Alliance has intervened in the local water rights permit for Zone 7 Water Agency, over concerns about adequate flows and habitat for steelhead trout. Zone 7 is undertaking an environmental and hydrologic analysis to assist in reaching resolution on our protest. Zone 7 is studying instream flow, critical fish passage locations, potential habitat utilization, and opportunities for habitat enhancements in the arroyos.

Zone 7 Water Agency is planning for multiple fish passage projects in Arroyo Mocho, Arroyo del Valle, and Arroyo de la Laguna as part of their Stream Management Master Plan projects in Livermore and Pleasanton. The Zone 7 plan proposes about a dozen restoration and enhancement projects which will remove or modify fish passage barriers, restore natural stream meander, plant riparian vegetation or replace non-native vegetation with native plants, create wetlands and other habitat for sensitive species, and install educational kiosks. Although there appear to be a few traditional flood control projects that involve hardening stream banks in already-altered stream reaches, most of the proposed flood protection and erosion control projects appear to be quite visionary and take environmental and habitat consideration into account.

Zone 7 has completed numerous fish passage projects in the northern watershed: multi-agency projects to stabilize stream banks and restore lower Arroyo de la Laguna in 2006 and 2011; removal of Granada Fish Barrier from Arroyo Mocho in 2007; installation of fish ladders on Arroyo Mocho and Arroyo Las Positas in 2003; and removal of the Stanley Boulevard Weir and the Castlewood Drop Structure in 2013.