Hidden wetlands of Alameda Point

In the southwestern corner of Alameda Point – on the wildlife refuge – are 30 acres of wetlands.  They lie within the cleanup area known as Site 2.  The wetlands themselves are not contaminated, but due to protracted cleanup efforts and studies elsewhere on the site, the entire area has been off limits since the base was closed in 1997.

In May 2012, the Navy released a draft plan for covering the old underground waste disposal area on Site 2 with clean soil and seeding it with native grasses.The plan also includes a study of the wetlands on the site.  Here are some highlights from the wetlands report, and also some photos taken by a Navy contractor a few years ago during investigative work.

The wetland delineation report prepared for the Navy identified three distinct wetland and water features:

Site 2 wetlands. Navy contractor photo.

Open Water/Mudflat – Open water/mudflat is found in two large ponds, the North Pond and the South Pond.

The North Pond is connected to San Francisco Bay by a 36-inch-diameter culvert that penetrates the perimeter berm and seawall.  “The culvert appears to be appropriately sized to allow full tidal exchange on a diurnal basis, as the tidal wetland drains and fills completely twice a day,” according to the report.

Of the South Pond, the report said, “Most of this pond is either shallow standing water or mudflats, with a fringe of pickleweed (Salicornia virginica) forming the transitional plant community between the mudflats and nearby uplands.  Freshwater seasonal pond and transitional mudflat habitats such as this have been identified in the Baylands Ecosystem Habitat Goals Project (SFEI 2001) as rare and important habitat components.”

The Navy’s summary of the wetlands report goes on to say, “The South Pond and mudflat matrix is high-value habitat in that it offers high tide refugia for wading shorebirds, and low tide refugia for ducks and geese. Because pond water surface elevations in this area are maintained by groundwater and precipitation, they do not fluctuate on a diurnal basis as they do in the northern (tidal) pond. Since this area normally has both mudflats and open water, it is available as foraging habitat year-round. At the time of the reconnaissance survey in late October [2011], an estimated 500 birds representing at least eight species were observed foraging in this pond and mudflat.”

Seasonal wetlands – One area on the north side of the site is considered low quality and will be covered by the soil cap.  The lost wetland acreage will be replaced at other locations on the site.  At the south end of the site is another seasonal wetland.

Tidal wetlands are found surrounding the North Pond that is connected to San Francisco Bay.

Seasonal wetlands, Site 2, Alameda Point. Navy contractor photo.
Site 2 wetlands, Alameda Point, southwestern corner. Navy contractor photo.
Wetland Mitigation Plan Proposed Site 2. Navy graphic.
Wetland Mitigation Plan Proposed Site 2, with legend. Navy graphic.

Author: richard94501

My blog is Alameda Point Environmental Report covering environmental issues from wildlife to cleanup at the former Navy base in Alameda now called Alameda Point. Articles on my blog are frequently printed in the Alameda Sun newspaper. I also host a Twitter site and a Flickr photo site. I hope you find my stories and photos of interest. Richard Bangert Alameda, California

2 thoughts on “Hidden wetlands of Alameda Point”

  1. Most contaminants in this former military dump site are Not being cleaned up. They will remain with a few feet of soil on top.

    How is that a “Cleanup”?

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    1. The term “cleanup” is used here as the common vernacular to refer to the site. You are correct in pointing out that most of the contaminants at this site will not be cleaned up, but instead covered up. This remediation alternative was chosen mainly because the cost of complete removal would have been $900 million. Removal also would have brought with it a new set of environmental concerns, namely hazardous dust, worker safety, transport safety, fuel consumption, and moving the problem somewhere else. Due to the distance from the shore, and lack of contaminant migration to the bay, the Navy and regulators chose to leave the waste in place.

      While the underground “waste cells” are staying in place, there have been various removal (cleanup) actions over the years, mainly regarding radium-contaminated waste.

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