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

  • Construction Update- Week of August 14, 2017 - Last week, (week of August 7) the contractor had to deal with high water levels in Peyton Slough causing water to leak into pond C. The main work items last week involved dewatering pond C and re-drying the soils there. The contractor also continued to dry/moisture condition soils in ponds D and E. This week […]
  • Construction Updates– Week of July 17, 2017 - Following is a summary of main work items during the week July 17, 2017: •Completed vegetation removal and drying in Ponds C, D and E (except small area by tree with nest, pond C). •Continued ripping and drying the soils in ponds C, D and E. •Continued dewatering local ponding water in Pond E. •Wallace-Kuhl […]
  • Construction Updates – Week of July 10, 2017 - Week of July 10, 2017 Continue vegetation removal and drying in Ponds C, D and E. Continue dewatering in Ponds D and E. Continue Soil drying Ponds C, D and E. Haul and dispose of vegetation – starting primarily 7/9/17 for approx. 1 week. Stockpile asphalt/debris from ponds. Install rock and grade on access road.
  • Construction Updates – Week of July 3, 2017 - Week of July 3, 2017 Continued vegetation removal and drying in Ponds C, D and E. Continued dewatering in Pond D. Began dewatering in Pond E. Soil drying Ponds C, D and E.
  • Construction Updates – Week of June 26, 2017 - Week of June 26, 2017 Notice to Proceed (NTP) was issued to Water Rock Construction on June 14, 2017.  NTP allows the contractor to begin work on the project. Public access to Moorhen Marsh was closed on June 14, 2017 in order to allow the contractor to begin working in the marsh. Once the NTP […]

Construction Photo Gallery

Construction Videos

Breaking Ground

Entering Pond E for the first time

Removing Vegetation

Removing Vegetation in Pond D

Grading Soil in Pond D

Vegetation Removal in Pond E

Soil Ripping in Pond E