Large water-filled "bladder dams" were to be installed on a tributary of Pescadero Creek today to block the flow of a toxin responsible for annual kills of juvenile salmon and steelhead trout that have plagued the South Coast for more than a decade.

Several government and conservation groups including the National Oceanic and Atmospheric Administration, California State Parks, California Department of Fish and Game, Coastal Conservancy, Native Sons of the Golden West, and California Trout have worked together to install the dams which will prevent water flows containing hydrogen sulfide from entering the creek.

A naturally-occurring element, hydrogen sulfide is rendered harmless when diluted with oxygen-rich water but can be deadly when released into water conditions like those found in the creek during the spring and summer months when a sand bar arises, cutting off the creek from the ocean.

The collapsible dams will allow engineers to block the hydrogen sulfide flow in these times and let the water back in during the winter when storms have washed away the sand bar and oxygen levels are higher.

The project is expected to cost as much as $14,000 and will be paid for with public and private sources, according to a release from California Trout.

• Half Moon Bay Review