The Moorhen Marsh Western Pond Turtle Enhancement Project

About The Project

In 1974, led by an innovative Board of Directors, MVSD became the first Wastewater Treatment Plant on the West Coast to utilize treated wastewater for wetland creation. The resulting Moorhen Marsh saved the District’s rate payers millions of dollars by eliminating the need for a deep water outfall while establishing a 21-acre habitat that benefits numerous aquatic and terrestrial species. Almost 40 years later, MVSD produced the Moorhen Marsh Management Plan which calls for significant improvements to this historical wetland.

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These planned improvements are the Moorhen Marsh Western Pond Turtle Habitat Enhancement Project (Project) and will take place in two phases: Phase A in 2017 and Phase B in 2018 (see map). The Project involves wetland and riparian habitat enhancements, the excavation of marsh ponds and Peyton Slough, the replacement of water control structures, levee restoration, and visitor access and facility improvements including a new ADA trail and board walk, several new dip netting areas for students, and a rare wetlands plant garden.

Pre-construction activities for Phase A including pond dewatering, fish rescue, vegetation cutting, and wildlife exclusion fence installation will run between January and April 2017. The Phase A improvements will be constructed between mid-June and November of 2017. As proposed, the Phase B timeline in 2018 will mimic the Phase A schedule.

During Phase A construction, Moorhen Marsh will be closed to the public from mid-June through November 2017. Phase B construction will likely close the marsh mid-May through November 2018. Come back regularly for Construction Updates or visit our Facebook page ( for the latest information on construction progress. If you are uncertain about access, please call 925-228-5635 x10.

MVSD regrets any inconvenience to our wetland visitors that may be caused by the Project. Please be patient as we work to improve this important wetland for wildlife and human visitors alike.

Construction Updates

  • Moorhen Marsh Phase B- Construction Week of August 20, 2018 - Recent work performed: Completed levee reconstruction with geogrid in pond A-2 and A-1. Constructed 3 islands in pond A-2 and began island construction in pond A-1 Formed and poured concrete for the boardwalk and viewing platform abutments in pond A-2. Installed timber piles for the boardwalk and viewing platform abutments in pond A-2. Installed 2 […]
  • Moorhen Marsh Construction Update- Week of July 2, 2018 - Recent work performed: Dewatering and fish rescue in ponds A1, A2, B and Fat Slough Vegetation removal and drying. Turning soil with a long-reach excavator and dozers in dewatered pond beds to further dry the soil. Installation of fused HDPE to divert water in Peyton Slough. Installation of sandbag cofferdam at upstream end of Peyton […]

Construction Photo Gallery


Construction Videos

See Phase A activities >