The Model/Friendship Marsh

History:

Before being diked and filled for agricultural and military purposes, the model marsh site had been a fully functional salt marsh.  These human activities in this area along with the natural sedimentation from storm events caused a decrease in the tidal flow and accelerated system degradation to this area.

Overview:

In order to re-create the variety of habitats usually present across the intertidal marsh plain, expand the area for wetland flora and fauna, and create a coastal habitat that can function similarly to a natural system, artificial tidal creek networks were excavated and native plants were re-vegetated on the restoration site. The Model Marsh as well as a surrounding 500 acre area was later dedicated under the name of Friendship Marsh.

Description:

Environmental Alterations

Goal 1:

Excavate former salt marsh filled in by natural and anthropogenic events to create a marsh plain with a variety of habitat types and to simulate a natural network of tidal channels.

Initiially, the mouth of creek networks experienced large sediment depositions (0.4-0.5 m worth), but this gradually decreased. At first, small channels began forming at creek mouths, implying that the mouths would deepen and revert to the original, natural morphology. However, the upper portion of creeks changed little over time and sediment accumulation became greater in the mudflats than in cordgrass or marsh plain areas. The monitored cells without creeks gained more sediment while the cells with creeks retained and facilitated water flow longer than those without because of sediment transportation abilities.
After five years, volunteer creeks unfortunately did not achieve restoration dimension and drainage targets.

Goal 2:

Create a variety of habitats to simulate a natural creek network system.
Pacific cordgrass (Spartina foliosa) was planted with different spacing and kelp soil amendments to find the most effective planting method.  Saltwort was planted as well on the site while pickleweed was naturally recruited. Glasswort, another salt marsh plant, experienced nearly 100% survival when placed in the area. Kelp soil amendments were used to change the physical property of the soil, and thus aid the re-vegetation of the site.

Click here for Post-Restoration Developments

Timeline:

-Excavated approximately 2m of accumulated sediment (winter 1999)
-Model Marsh excavated (January 2000)
-Model Marsh opened to tidal flushing (February 2000)
-500 acre restoration area and Model Marsh dedicated as Friendship Marsh (April 29, 2000)

Bibliography/Sources:

Morzaria-Luna, Hem N. “Determinants of Plant Species Assemblages in the Californian Marsh Plain: Implications for Restoration of Ecosystem Function.” University of Wisconsin-Madison, 2004

Zedler, Joy. Handbook for Restorting Tidal Wetlands. CRC Press LLC. New York, 2001

Personal Contact- Serena Moseman