Parsons Slough is a 450-acre complex of mudflats and other tidal wetlands. This area historically supported 400 acres of tidal marsh, but now only 35 acres remain. In the first half of the twentieth century the area was diked off from the tides and drained for farming. The marsh soils dried and shrunk, lowering the land surface in a process called subsidence.
In late 1982, shortly after the land was acquired by the California Department of Fish and Game, the dikes around Parsons Slough broke. When the tides returned, currents, tidal scour and marsh loss accelerated throughout Elkhorn Slough.
Parsons Slough makes up 15 percent of Elkhorn Slough by land area, but because of subsidence it accounts for 35 percent of the daily exchange of tidal waters by volume. Powerful currents now prevent the establishment of salt marsh in Parsons Slough and contribute to tidal scour and the die back of salt marsh in the rest of the estuary.
Reducing tidal exchange at Parsons Slough would slow currents in many parts of Elkhorn Slough, increasing the viability of salt marsh and soft mud habitats throughout the estuary. Salt marsh can also be restored in Parsons Slough by adding sediment to raise the elevation of subsided former marshes.
The Parsons Slough planning process is evaluating how these strategies can be implemented to preserve Elkhorn Slough salt marshes and soft mud habitats while protecting the high quality existing habitat in Parsons Slough for sharks and rays, sea otters, seals and shorebirds.
We welcome your insights and contributions to the process.
Parsons Slough Project Update (6-3-09, 105KB, .pdf)
Parsons Slough Wetland Restoration Plan
We invite you to download the documents and provide comments. Each comment should identify the specific document title, page and line number associated with the comment. If the comment is more general, feel free to just use the word 'general'. Comments are now being accepted.
Parsons Slough Adjustable Sill Concept Modeling (.doc, 2.18MB)
There are five draft documents:
Draft Executive Summary (65KB .pdf)
Draft Existing Conditions Report (3.24MB .pdf)
Draft Sediment Additions Report (2.37MB .pdf)
Draft Alternatives Analysis Report (5.02MB .pdf)
Draft Restoration Plan (3.31MB .pdf)
These are also bundled together into a file called
Draft Final Report: Parsons Slough Restoration Plan (15.13MB .pdf)
The Tidal Wetland Project hosted a series of meetings on Dec. 2, 2008 to advance the Parsons Slough Restoration Project. Notes, presentations and comment forms from these meetings are available by clicking below:
Parsons Slough Restoration Team meeting notes (70KB .pdf)
JOINT Science Panel and Strategic Planning Team meeting notes (52KB .doc)
Parsons Slough Restoration Project Public Meeting notes (37KB .doc)
Parsons Slough Project presentation (Bryan Largay, ESNERR) (3.54MB .pdf)
Parsons Slough Draft Restoration Plan presentation part 1 (Chris Webb, Moffatt & Nichol) 1.7MB .pdf
Parsons Slough Draft Restoration Plan presentation part 2 (Chris Webb, Moffatt & Nichol) 2.1MB .pdf
Parsons Slough comments sheet (116KB .pdf)
We welcome your questions and comments.
The State Coastal Conservancy (SCC), working closely with the Elkhorn Slough Reserve and Elkhorn Slough Foundation, has hired a consulting team led by Moffatt & Nichol to provide consulting services to develop a Parsons Slough Wetland Restoration Plan. The Plan will evaluate tidal marsh restoration alternatives for Parsons Slough including actions to reduce the tidal prism in the area and/or add sediment to rebuild marsh elevations. This Plan is part of the Elkhorn Slough Tidal Wetland Project.
Additional details about the project scope can be found in the Request for Services (.pdf 597KB), in the Project Work Program (.doc 65KB), and in the Project Goals and Objectives (.doc 51KB).
2005 Aerial Photo of Parsons Slough |
Schedule of Deliverables |
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Conduct initial team meeting to establish goals and objectives for the project. Develop the list of goals and objectives as a draft and modify it after input from attendees. Deliverable: List of Goals and Objectives (Draft and Final). |
Expected July 30, 2007 |
Prepare a Quality Assurance Project Plan (QAPP) for use of existing and new data. Deliverable: Quality Assurance Project Plan (Draft and Final) |
Expected August 3, 2007 |
Prepare an Existing Conditions Report (ECR) as the baseline for subsequent environmental review. Identify existing data on habitat, birds, fish, invertebrates, hydrology, water quality, and soil character and quality. Determine habitat types, sensitive species, distributions, and values. Prepare a GIS habitat map and a matrix of acreage types. Deliverable: Existing Conditions Report (Draft and Final) |
Expected December 12, 2007 |
Analyze options to add sediment to Parsons Slough to raise marsh elevations. Consider sediment sources, costs, construction methods, fill sequencing, regulatory issues, and environmental impacts. Deliverable: Options for Sediment Additions Report (Draft and Final) |
Expected April 21, 2008 |
Develop and evaluate four restoration options including No Action. Illustrate and describe concepts, model hydraulics, estimate expected habitat areas, estimate sediment quantities, construction techniques, construction costs, and maintenance needs. Perform preliminary environmental review. Deliverable: Alternatives Analysis Report (Draft and Final) |
Expected May 30, 2008 |
Prepare the Parsons Slough Restoration Plan to include an CEQA Initial Study checklist for the preferred alternative sufficient for CEQA review, and applying for permits and grant applications. The level of detail will be towards the 30% design level. Deliverable: Restoration Plan (Draft and Final) |
Expected December 12, 2008 |
Parsons Restoration Team (PRT) Current Participants:
Trish Chapman1
California Coastal Conservancy |
Jim Oakden
Moss Landing Marine Laboratories |
Becky Christensen
Elkhorn Slough National Estuarine Research Reserve |
Barb Peichel1
Elkhorn Slough National Estuarine Research Reserve |
Ross Clark
California Coastal Commission, Central Coast |
Mary Root
U.S. Fish and Wildlife Service, Ventura |
John Krause
California Department of Fish and Game |
Peter von Langen
Regional Water Quality Control Board, Central Coast |
Cheryl McGovern
U.S. Environmental Protection Agency, Region 9 |
Lisa Windham
U.S. Geological Survey |
Bill McIver
U.S. Fish and Wildlife Service, Ventura |
Andrea Woolfolk
Elkhorn Slough National Estuarine Research Reserve |
Katie Morange
California Coastal Commission |
1 – Project Managers |
Parsons Slough Restoration Planning Consultant Team Leads:
Moffatt & Nichol |
Chris Webb1, Dilip Trivedi1 |
Chambers Group, Inc. |
Noel Davis |
Wetlands & Water Resources |
Stuart Siegel |
FarWest Restoration Engineering |
Roger Leventhal |
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1 – Project Leads |
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