Dredging, Wetlands Creation, & Ecosystem Protection: Finding the Right Balance for SF Bay LTMS Methylmercury and Dredging Symposium January 28, 2010 Dyan.

Dredging, Wetlands Dredging, Wetlands Creation, & Creation, & Ecosystem Ecosystem

Protection: Finding Protection: Finding the Right Balance the Right Balance

for SF Bayfor SF Bay

LTMS Methylmercury and LTMS Methylmercury and Dredging Symposium Dredging Symposium

January 28, 2010January 28, 2010Dyan Whyte, Assistant Executive Dyan Whyte, Assistant Executive

OfficerOfficer

Framework for addressing

Mercury in SF Bay is the

TMDL

Established Water Quality Established Water Quality Objectives for SF BayObjectives for SF Bay

0.2 ppm mercury in large predator fish

0.03 ppm mercuryin prey fish

California least tern

TMDL Implementation TMDL Implementation Dredging and In-Bay Dredging and In-Bay

DisposalDisposal Load Allocation = Zero Load Allocation = Zero

Implement LTMSImplement LTMS Restrictions on In-Bay DisposalRestrictions on In-Bay Disposal

Sed. Hg conc. < ambient (0.53 ppm)Sed. Hg conc. < ambient (0.53 ppm) Operations shall not cause an increase in Hg Operations shall not cause an increase in Hg

bioavailabilitybioavailability

TMDL TMDL ImplementationImplementationWetlands Creation & Wetlands Creation &

RestorationRestoration

No net increase in Hg or MeHg loads No net increase in Hg or MeHg loads Requirements in WDRs/401 WQ Certs to Requirements in WDRs/401 WQ Certs to

manage existing wetlands and ensure newly manage existing wetlands and ensure newly constructed wetlands are designed to minimize constructed wetlands are designed to minimize MeHg production and biological uptakeMeHg production and biological uptake

Pre- and post-restoration monitoringPre- and post-restoration monitoring Adaptive ImplementationAdaptive Implementation

Dredging + Desire for More Wetlands = Beneficial Reuse

Cover and Non-cover reuse requirements

Non-cover subject to strict controls Min 3 feet below surface at anaerobic

depths below tide line Min 200 feet from future higher order

channels

Current Approach to Adaptive Management

BiosentinelsBaselineTriggersEvaluate management actions

Learning project by project

Discussion Discussion TopicsTopics

RMP Hg strategy asks the right questions, is enough being done to answer them?

Identifying the right biosentinels & triggers is critical

How reversible do actions need to be?

Regional Monitoring Approach – Is there a need to formalize?