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Lessons Learned From Wetland Restoration Projects

Restoration or rehabilitation of wetland systems and communities is an adaptive process. Before beginning a project, it is essential to have a good understanding of the dynamics and elements of a site, clearly defined goals, and identified desired future conditions. However, forces of nature and unknown elements of site can alter your well-designed plan. Monitoring, adaptive management, and long term maintenance become equally important elements and tasks of successful projects. Sharing lessons learned from our projects can help improve the success of our own and others' restoration efforts.

We will post new lessons learned from restoration efforts around the state when they become available.

Estuarine Restoration: South Slough National Estuarine Research Reserve
Coos Bay, Oregon

For more information on the specific projects described below, or results of ongoing monitoring, contact Craig Cornu at South Slough National Estuarine Reserve. 541-888-2581. Ext. 301, craig.cornu@state.or.us

White Pelicans

White Pelicans
(Dave Menke, U.S. Fish & Wildlife Service)

Restoration Approach

  1. Use South Slough National Estuarine Research Reserve as an outdoor lab to test innovative restoration techniques
  2. Restore to pre-contact conditions as represented by relatively undisturbed reference sites in the Reserve
  3. Use self design methods (manipulate key site attributes and allow natural processes to do the rest of the work)
  4. Demonstrate "accessible" restoration methods within reach of most restoration practitioners
  5. Focus largely on "single family": salmonidae a.k.a. salmonids
  6. Projects are adaptive on multiple levels:
    • Take corrective actions at sites based on project monitoring information
    • Apply lessons learned from each project to future projects in the Reserve
    • Projects contribute to broader regional/national efforts to improve the science
    • Practice habitat restoration by testing and evaluating experimental or innovative methods

Kunz Marsh

Major Issues:

  • Subsided marsh surface (0.80 m) caused by diking and drainage
  • Little or no salmonid access to marsh plain/edge
  • Tidal channel network reduced to linear ditches
  • Little or no connection with rest of estuary (nutrient exchange)

Lessons Learned:

  1. Manipulating the marsh surface to mid marsh elevations provided conditions favorable for relatively rapid colonization by emergent marsh vegetation while allowing channel development over time.
  2. Manipulating the marsh surface to low marsh elevations resulted in slower vegetation community development but allowed channel development and benefitted more fish in the early stages.
  3. Manipulating the marsh surface to high marsh elevations sacrificed channel development for rapid vegetation colonization.
  4. Channels developed initially by erosion/headcutting at different rates depending on marsh elevation, gradient and path of small tributary creek.
  5. Fill material at the project site consolidated as predicted and did not get exported offsite.

Dalton Creek

Major Issues:

  • Tidal channel network reduced to linear ditches
  • Little or no salmonid access to marsh plain/edge
  • Little or no connection with rest of estuary (nutrient exchange)
  • Logistical: No access to marsh surface for excavating equipment except tracked vehicles between muted tides

Lessons Learned:

  1. The use of explosives was a viable and cost effective channel construction strategy (given specific conditions).
  2. The establishment of a pilot channel appears to be a viable and cost effective strategy to initiate or restore establishment of tidal channels.
  3. Constructed ditches overfilled with dike material appear to remain filled over time.
  4. Juvenile coho appeared in the upper Dalton Creek tidal channel at their first opportunity, and have been observed in the pilot channel in subsequent years.
  5. Chronic stream turbidity did not appear to an issue for this project the pilot channel was observed to be turbid only intermittently during the first winter after channel construction.
  6. Bury large wood in pilot channels to truly incorporate structure in channel development.
Lower Klamath National Wildlife Refuge, Oregon

Lower Klamath National Wildlife Refuge, Oregon
(Dave Menke, U.S. Fish & Wildlife Service)

Anderson Creek

Major Issues:

  • Nontidal channel network reduced to a linear ditch
  • Severe ditch downcutting no hydrologic connection between stream and floodplain
  • Salmonid habitat reduced in abundance and complexity
  • Beaver pond habitat confined to linear ditch. Suspected turbidity caused by "banging" of ditch

Lessons Learned:

  1. The establishment of a pilot channel appears to be a viable and cost effective strategy to initiate or restore establishment of tidal channels.
  2. Some water quality impacts (high summer stream temperature) resulting from relocating the channel appear to be temporary and manageable.
  3. Other potential water quality impacts (turbidity) did not materialize.
  4. The aggressive native vegetation seeding and planting appears to have contributed to a plant community that is outcompeting reed canary grass.
  5. In non-tidal wetlands, adaptive management is required the first 35 years (or more?) after project construction to help ensure that native plants are outcompeting invasive plants.
  6. Bury large wood in pilot channels to truly incorporate structure inchannel development.

Authored by Esther Lev, Executive Director, The Wetlands Conservancy (2009)

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