“Its All About the Sediment” San Francisco Bay “Its All About the Sediment” Brenda Goeden San Francisco Bay Conservation and Development Commission

Approximately 54 Square Miles Today San Francisco Bay Approximately 54 Square Miles Today Two Major Fresh Water Rivers to the East: Sacramento and San Joaquin Drain 40% of the state The San Francisco Bay proper, covers 54 square miles, almost a third smaller than it was before development of the region. It has two very large rivers which drain 40 percent of the landmass of the state of California through the Delta. It is an estuary made up of a primarily mud bottom, but has high energy areas that are sandy as a result. BCDC’s jurisdiction includes the Bay itself, certain named waterways, the adjacent marshes and 100 feet landward of mean sea level. This is an important consideration when examining the possibility of a sediment management program for the region. We are a bit in the middle space between the rivers that bring the sediment into the system and the outer coast.

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The New World: Sea Level Rise Changed Situation The New World: Sea Level Rise Area subject to high tide with 16 inches of sea level rise The 100 year storm: Areas at risk to 1/100 chance of flooding per year, In 50 years the Bay’s 100 year storm will be high tide Current 100-year flood plain

Floods Storm Surge

Shoreline and Beach Erosion

The New World: Sediment Deficit Changed Situation The New World: Sediment Deficit Point San Pablo, mid-depth, Dave Schoellhamer, USGS

Why Do We Care? Shorelines Levees Habitat Sea Level Rise

What’s Changed? The System? Our Understanding of the System? Sediment Rich Sediment Poor

1990/2011 San Francisco Bay Historic marshes diked off Historic beaches no longer connected Watersheds channelized Watersheds clogged with fine grain sediment Sediment trapped behind dams Shoreline developed Water from Delta controlled

Sediment Supply Shift: from the Delta to local tributaries Changed Situation Sediment Supply Shift: from the Delta to local tributaries Where we used to see the Delta as our main source of sediment, we now will need to look to our local watersheds to supply the sediments to sustain our shorelines, beaches and marshes. Oakland Museum Creek Guide

A Large Water and Sediment-shed

Local Tributaries are Becoming Increasingly Important Clemson University

Embayments: Erosional & Depositional San Pablo Bay - Erosional Central Bay - Erosional South Bay - Depositional Fregoso, Jaffe, Foxgrover, USGS

Ebb-Tide Delta Erosion Sediment Removal from system Changed wave refraction Erosion along outer coast Dallas & Barnard, USGS

Sand mining removing sand Sand appears slow to replenish Patrick Barnard & Rikk Kvitek

Dredging Projects Federal Channels Ports Refineries Marinas The biggest area in which we can manage sediment is in dredging projects. We have approximately 90 dredging projects in the Bay, including federal navigation channels, ports, refineries and marinas. This represents between 3 and 4 mcy of sediment dredged each year, down from a high of 6 mcy.

Ocean Disposal Site In-Bay Disposal Sites Alcatraz San Pablo Bay Carquinez Strait Suisun Channel Historically dredged material had been disposed at various sites around the Bay. Changes to agency dredging programs lead to the designation of four in Bay disposal sites and one site adjacent to the main ship channel entering the Bay. Ocean Disposal Site

Dispersive In Bay sites Carquinez San Pablo Alcatraz LTMS EIS/EIR

Ocean Disposal Removes Sediment from the System

FINAL EIS/EIR LTMS MANAGEMENT STRATEGY FOR THE PLACEMENT OF DREDGED SEDIMENT IN THE BAY AREA Percent of all Disposal Through a number of studies and completion of and EIS/EIR, the LTMS strategy focused on reusing as much dredged sediment as possible, targeting a maximum of 20% of in Bay disposal, a minimum of 40% beneficial reuse and the remaining 40% or less disposed of at the deep ocean disposal site.

HAMILTON WETLANDS WITH BEL MARIN KEYS PARCEL V ADDITION MONTEZUMA WETLANDS HAMILTON WETLANDS WITH BEL MARIN KEYS PARCEL V ADDITION Two additional restoration projects – a private project in Collinsville is the Montezuma project. The second is the Hamilton Wetlands project in Novato, with the addition of Bel Marin Keys V as part of WRDA 2007, brought the project to 2100 acres and a needed 24 mcy of dredged sediment. The Hamilton project is a federal/state/industry partnership with 3 mcy of sediment coming from the Port of Oakland 50 foot deepening project, the Coastal Conservancy being the State Partner and the Corps being the federal partner.

SONOMA BAYLANDS Our first major effort was the Sonoma Baylands: ~2.5 million cy of clean dredged material from the Port of Oakland -42-foot deepening project was used to create 322 acres of tidal and seasonal marsh and endangered species habitat. Dikes were breached and tidal action reintroduced in 1996. 12 years later, it is transitioning nicely into a restored and healthy marsh. Without dredged sediment placement, it is likely that this site would take 50 years to a restored state.

In An Ever Changing World “New” Issues to Contend With… Watershed Management Shoreline Protection Climate Change Habitat Restoration and Maintenance Sediment Supply and Demand Dredging and Aggregate Mining

Regional Sediment Management Is… The integrated management of littoral, estuarine, and riverine sediments to achieve balanced and sustainable solutions to sediment related needs.” Regional sediment management recognizes sediment as a resource. Sediment processes are important components of coastal and riverine systems that are integral to environmental and economic vitality.

Shorelines, Marshes and Beaches need sediment to keep up with sea level rise Prbo study with PWA PWA & PRBO in review

Flood Protection is a Key Component in Regional Sediment Management Walnut Creek Need to Find New Ways to Protect From Flooding and Support Sediment Supply to Wetlands and the Bay Ballona Creek

To Respond to a Changing Bay, A New Approach and Much Coordination is Needed

Management Considerations and Planning Scientific Inputs Management Considerations and Planning of Programs Affecting Sediment Supply and Demand Optimized Management

New Areas to Consider Sediment Sources and Sinks Flood Protection Aggregate Mining Dredging Wetland Restoration Beach Nourishment Shoreline Protection

Local Tributaries Sediment Flow Analysis Quantify local tributaries contribution to Bay sediment budget Corte Madera & Alameda Creeks Sediment gauges at head of tide and creek mouth Sediment flow and flux between creek and Bay Short term study – need funding to continue First step in developing a predictive numerical model for local tributaries Working with SFEI and USGS

Corte Madera Creek Study Wetland wave attenuation study Resilience of tidal marsh to sea level rise and coastal flooding Improve analytical tools for assessing flood risk Improve guidance for local decision makers Use data to build and calibrate 2D and 3D models Collect and analyze sediment cores for sedimentation rates and peat accumulation Working with USGS and Marin County Flood Control & Water Conservation District

Modeling Can Help Tidal Hydrology Watersheds Sediment Transport

Flood Districts and Watersheds Need Flood Districts and Watersheds