The official website of the Elkhorn Slough Foundation and Elkhorn Slough National Estuarine Research Reserve
Tidal Wetland Project: About TWP

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the Tidal Wetland Project.

Project Goals

The Elkhorn Slough Tidal Wetland Project is a collaborative effort to develop and implement strategies to conserve and restore estuarine habitats in the Elkhorn Slough watershed. It involves over a hundred coastal resource managers, representatives from key regulatory and jurisdictional entities, leaders of conservation organizations, scientific experts and community members.

The main goals of the Tidal Wetland Project are to:
(1) conserve existing high quality estuarine habitats
(2) restore and enhance degraded estuarine habitats
(3) restore the physical processes that support and sustain estuarine habitats.

Particular emphasis in the restoration planning process has been placed on the first goal, which aims to stop the ongoing marsh loss and estuarine habitat erosion in Elkhorn Slough.

Download the Elkhorn Slough Tidal Wetland Strategic Plan

Vision, Goals, Objectives, and Strategic Planning Principles for the Elkhorn Slough Tidal Wetland Plan
(7/29/05, Word doc, 70KB)

Black crowned night heron

Project Background

Elkhorn Slough contains approximately 2,690 acres of distinct habitat types. This includes 293 acres of subtidal channels and tidal creeks, 1,605 acres of mudflats, and 796 acres of intertidal salt marshes and tidal creeks. These habitats provide a rich ecosystem for over 340 bird (135 aquatic species), 550 marine invertebrate, and 102 fish species.

Over the past 150 years, human actions have altered the tidal, freshwater, and sediment processes that are essential to support and sustain Elkhorn Slough’s estuarine habitats.

  • Approximately 50 percent, or 1000 acres, of the tidal marsh in Elkhorn Slough has been lost since 1870 due to human activities.
  • Major physical modifications to the estuary have caused and are currently causing high rates of habitat loss and degradation in Elkhorn Slough.
  • Human impacts have resulted in ongoing marsh loss and estuarine habitat erosion, degraded water quality conditions, increased levels of pollution, eutrophication, and increased numbers of invasive species.
  • Almost 73,250 cubic yards of sediment are exported each year from Elkhorn Slough into Monterey Bay from habitat erosion.
  • Bank erosion rates along the main channel of Elkhorn Slough range from 1 to 2 feet per year. These rapid changes not only affect the estuary’s animals and plants, but also impact neighboring private lands, public access sites, and railroad and road infrastructure.

Broad restoration strategies have been developed by the Tidal Wetland Project teams to conserve and restore Elkhorn Slough’s estuarine habitats. The first key restoration strategy aims to reduce interior marsh dieback and estuarine habitat erosion. The restoration alternatives included under this strategy propose to change the estuary’s entrance to reduce the tidal influence and habitat erosion and restore or add sediment to promote marsh growth. The next step for this strategy will be to make a decision about whether to pursue a large-scale restoration project for Elkhorn Slough based on ongoing technical evaluations.

The purpose of the second restoration strategy is to restore and enhance degraded estuarine habitats in Elkhorn Slough. These restoration alternatives include actions to restore marsh habitat in the Parsons Slough and North Marsh wetland complexes, enhance water quality conditions in degraded areas, and restore tidal brackish marsh habitats. The next steps will be to obtain funding for a Parsons Slough restoration project, priority research and monitoring activities, restoration planning for degraded wetland sites, and pilot restoration projects.

The implementation of restoration projects requires a thorough understanding of relevant regulations, technical and political feasibility, funding needs, stakeholder interests, and research gaps. Potential large-scale restoration projects to reduce interior marsh dieback and habitat erosion in Elkhorn Slough are being evaluated over the next few years using an ecosystem-based management approach. The analysis of options to modify the estuary’s entrance and add sediments to rebuild marshes will include predictions about changes to tidal hydrodynamics, morphology, estuarine habitats and species, water quality, socioeconomic values, and political constraints. Restoration planning has been initiated for the Parsons Slough wetland complex. Funding is needed to support restoration projects, priority research and monitoring efforts, and community involvement activities.


Grant funding for this project has been provided by the National Oceanic and Atmospheric Administration’s Coastal Impact Assistance Program, David and Lucile Packard Foundation, Resources Legacy Fund Foundation, U.S. Environmental Protection Agency, and the California Coastal Conservancy. The project is being managed by the Elkhorn Slough National Estuarine Research Reserve, which is owned and managed by California Department of Fish and Wildlife in partnership with the National Oceanic & Atmospheric Administration (NOAA).

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This site is maintained by the Elkhorn Slough Foundation in partnership with the Elkhorn Slough National Estuarine Research Reserve