October 1996 Issues Online June 2007 April 2007 February 2007 December 2006 October 2006 August 2006 June 2006 April 2006 February 2006 December 2005 October 2005 August 2005 June 2005 April 2005 February 2005 December 2004 October 2004 August 2004 June 2004 April 2004 February 2004 December 2003 October 2003 August 2003 June 2003 April 2003 February 2003 December 2002 October 2002 August 2002 June 2002 April 2002 February 2002 December 2001 October 2001 August 2001 June 2001 April 2001 February 2001 December 2000 October 2000 August 2000 June 2000 April 2000 February 2000 December 1999 October 1999 August 1999 June 1999 April 1999 February 1999 December 1998 October 1998 August 1998 June 1998 April 1998 February 1998 December 1997 October 1997 August 1997 June 1997 April 1997 February 1997 December 1996 October 1996 August 1996 June 1996 April 1996 February 1996 December 1995 October 1995 August 1995 June 1995 April 1995 February 1995 December 1994 October 1994 August 1994 June 1994 April 1994 February 1994 December 1993 October 1993 August 1993 Select any issue from the menu in this bar.

Ports Tread Lightly on Ocean Floor

The "footprint" left on the seafloor by the several 100,000 cubic yards of material dredged from the region's ports and dumped at the Bay Area's new ocean disposal site in 1995 is the exact shape, size and depth scientists and planners thought it would be. As EPA managers tally up the final results a year's worth of seafloor mapping, sediment plume tracking and monitoring of impacts on bottom-dwelling critters, fisheries, seabirds and marine mammals at the site - which lies 46 miles west of the Golden Gate they're even more confident than before that the material is staying well within disposal site boundaries.

"It's so cool we're actually hitting the middle of a site that's 10,000 feet deep," says EPA's Brian Ross. According to Ross, physical mapping of where the dredged material ends up once it leaves the barges - it's "footprint" - shows a small area of deposits more than 17 cm thick smack in the center of the site. Surveys of the rest of the site indicate a dusting of no more than about two cm. thick (see map). This thin dusting isn't enough to smother the worms, crustaceans and other critters in the ocean floor oozes, says Ross, though organisms in the central target area did get buried. While fisheries survey results aren't yet complete, Ross says seabird and marine mammal observers on board barges saw no evidence of anything unusual - no avoidance or attraction. "There are no surprises, no violations, no exceedances of any criteria we set showing up in our monitoring results," says Ross.

EPA scientists plan to publish all this data in an annual report soon. But the no-adverse-impacts results are helping them make the case for extending current disposal limits and monitoring programs established for the site beyond a looming December 1996 expiration date. The 1994 official site designation set an interim annual disposal volume limit of six million cubic yards per year, based on the assumption that a permanent volume limit could be better set when environmental documentation for a proposed comprehensive package of Bay, ocean and upland disposal sites and options for the entire region was complete. Two years later this EIS/EIR for the Bay Area's LTMS (long-term management strategy for dredged material disposal - a six-year, multi-agency, public-private cooperative planning effort) is still only in draft form, so EPA is recommending an extension of the interim disposal limits for another two years. Ross says EPA will release a draft proposed rule extending existing interim management of the ocean site in late October, at which time the public can comment on several options for different volume limits and timeframes.

Contact: Brian Ross (415)744-1979

«To @@(newsletter_title)@@ Index

[ ABAG HOME | SFEP HOME ]

Copyright © 2002, San Francisco Estuary Project