Marin Independent Journal
Patience pays off for Bolinas Lagoon
Thursday, August 3, 2006
TO DREDGE or not to dredge: that is the question facing stakeholders debating the future of Bolinas Lagoon.
The circumstances may not be as dire as Hamlet's, but the decision certainly is vexing.
Several years ago, officials were ready to start dredging to "rescue" the lagoon. They said it was silting in and slowly becoming a meadow.
Environmentalists pressed for a second opinion and got one. They feared that dredging would do too much environmental damage to the lagoon. Now, another expert says the lagoon's transition - its loss of depth and the growth of mudflats - is natural and progress toward an equilibrium that won't lead to the loss of the lagoon.
"In 1996, there was an impression this would become a meadow ... in 25 years," Supervisor Steve Kinsey said after a presentation of a new study by Philip Williams & Associates.
The report says that core samples of the lagoon's soils and historic maps show the lagoon is following a natural cycle where its depth is increased by a significant earthquake followed by years of a buildup of sedimentation generated by the ocean and runoff.
The report says the sediment eventually reaches an equilibrium that shouldn't threaten to close the mouth of the lagoon to vital tidal flow.
Despite this conclusion, there are those who characterize this advice as a "do nothing and hope" approach when the fate of the lagoon, its habitat and its historic use for boating and fishing are at risk.
The Williams report admits that as this equilibrium is reached there would be a growth of mudflats and potential habitat shifts that would make the lagoon less suitable for some fish and birds. But others would thrive in the changing environs.
Humans will decide what to do next. The report suggests regular monitoring of sedimentation and some habitat improvements along Pine Gulch Creek and its mouth at the lagoon.
Supervisor Charles McGlashan summed up the latest expert advice as a "less is better" approach to solving the lagoon dilemma.
There's no question that dredging could not have been done without short- or long-term environmental consequences. If the lagoon's days are not numbered and dredging can be avoided, that's good news.
But there also needs to be regular and effective monitoring of the bay's sedimentation to make sure the mouth of lagoon remains open and its ecological viability is not compromised.
The report's conclusion that the lagoon is not in jeopardy and the changes likely are part of a natural trend should give pause to advocates pushing a plan for extensive dredging.