Biology Reference
In-Depth Information
voluted hydraulic systems in order to shunt the saltiest water in the sev-
enth pond through a mixing basin, where it could be diluted before being
returned to the bay.
The third Phase I project is taking place at the bottom of the bay, near
the old asparagus canning capital of Alviso. This small shoreline town sits
about 10 feet below sea level, surrounded by salt ponds, and is home to a
historic working class community. Here, the project may give the little
town its silt-choked marina back and reinvigorate the local shrimping in-
dustry. The plan involves tweaking some of the massive flood-control pro-
tections placed here by the U.S. Army Corps in the 1970s. By carefully
distributing new tides and runoff flows through the channels and ponds in
this complex, Orr plans to slowly scour out the silted-up channel. “We're
only going partway toward the long-term solution with Phase I. We need
to be able to change our approach in case we get undesirable flooding or
more mercury working its way up the food chain,” she says.
Whereas the North Bay mudflats include layers of gold-mining debris
containing mercury, the South Bay lies at the bottom of a watershed in
which mercury itself was mined for over 120 years (see also Map 8, p.
169). During this time, the New Almaden mine extracted over 84 million
pounds of quicksilver (mercury by another name) from the Santa Clara
Valley foothills. But not all of the mercury left the watershed in flasks.
Avocet being banded on the eastern levee of Pond A8, near Alviso, as part of South
Bay salt pond mercury contamination studies. Pond A8 is being carefully monitored
due to its location downstream of the New Almaden mercury mine. (Scott Demers)
