Posted by: pointreyesscience | May 4, 2009

Coastal Watershed Restoration Projects

Development near Limantour Beach in 1961.

Development near Limantour Beach in 1961. From NPS Archives.

Before Point Reyes National Seashore received protected status from the federal government, the area was privately held. Ranching operations began in the 1800s, followed in the 1950s by residential development near Drakes and Limantour Esteros. Naturally, this development brought along with it infrastructure – roads, dams, and culverts, among other things. Concern over the development and a desire for public coastal access led directly to the establishment of the Seashore in 1962. The Seashore continues to remove what legacy structures it can in an effort to provide a natural place for fish and other wildlife, as well as its human visitors. In 2006, the Seashore received $2.44 million in federal funding to undertake some of this coastal watershed restoration, and many of the projects were recently completed.

Dam Removal

A beach access berm was built at Limantour Beach in 1952, and Muddy Hollow Creek was dammed in the early 1960s to create a recreational pond for a proposed residential development. These dams obstructed tidal dynamics and fish passage for the federally threatened steelhead trout, and dramatically affected natural processes and habitat.

The National Park Service removed both of these dams to return the tides to more than 15 acres of coastal marsh habitat in the Estero de Limantour. Tidal influence provides everyday renewal of the sort created by a freshwater flood event. Smolting steelhead that researchers found in Muddy Hollow Creek prior to dam removal can now get to the ocean, and vegetation is changing from freshwater species to saltwater species, including pickleweed and cord grass. The freshwater/estuarine transition zones will also be able to shift with anticipated changes due to sea level rise.

As part of this project, the National Park Service rerouted Estero Trail, which used to follow the crest of Muddy Hollow Dam. They also replaced the beach access berm with a bridge to provide continued visitor access.

The old beach access path on top of a large berm.

The old beach access path on top of a large berm. Credit: NPS Photo.

The new beach access bridge, allowing tides to flow beneath it.

The new beach access bridge, allowing tides to flow beneath it. Credit: NPS Photo.

Road Crossing Replacement

Although roads are still needed throughout part of the Seashore, many of the structures associated with roads are outdated. Historically, road crossings over creeks were designed without regard to fish passage, preventing anadromous fish from moving freely and interfering with their life cycles.

The National Park Service removed two road crossing culverts that prevented fish passage on East Schooner Creek and replaced them with bottomless arch culverts. The old culverts resulted in three to five foot vertical drops, a major impediment to fish passage, and frequently overflowed during floods. The new culverts feature a natural streambed bottom that can adjust with changes in the adjacent streambed.

These culvert replacements decrease the risk of structural failure, reduce long-term maintenance needs, enhance habitat for federally threatened steelhead trout – allowing them to migrate freely from freshwater to ocean and back, and allow for the reintroduction of federally endangered coho salmon. They may also accommodate larger storm events that may result from a shift in natural variability as a result of climate change.

For more information about these and other coastal watershed restoration projects, please visit: http://www.nps.gov/pore/parkmgmt/planning_cwr.htm.

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Responses

  1. Hi, good post. I have been pondering this topic,so thanks for sharing. I will probably be coming back to your site. Keep up the good posts


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