Santa Barbara Channel

Anacapa

Island

Santa Cruz

 Island

San Miguel 

Island

Santa Rosa 

 Island

3 nautical mile State-waters limit

Goleta 

slide

Hueneme

 Canyon

Ventura

La 

Conchita

Point

Conception

Santa 

Barbara

SANTA YNEZ MOUNTAINS

Carpenteria

Goleta

Ventura Ventura

 River

Santa Clara

River

0 10 KILOMETERS

0 10 MILES

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2009–3077

October 2009

C A L I F O R N I A

Area of

map

N

Supporting Sound Management of Our Coasts and Seas Santa Barbara Channel 

U.S. Geological Survey (USGS)

Western Region: Santa Barbara Channel

Coastal and Ocean Science

USGS coastal and ocean science in the Western United 

States and the Pacific integrates 

scientific expertise in geology, 

water resources, biology, and 

geography. Operating from 10 

major science centers in the 

Western Region, the USGS is 

addressing a broad geographic 

and thematic range of important coastal and marine issues. 

In California, the Santa Barbara Channel represents one 

area of focus.

Santa Barbara Channel

The Santa Barbara Channel area extends 

from the steep Santa Ynez Mountains 

on the north to the Channel Islands and 

adjacent continental shelf on the south 

New high-resolution, shaded-relief seafloor map of Santa Barbara Channel.

New USGS Mapping 

The USGS is conducting a seafloor, habitat, and geologic mapping effort in the Santa Barbara Channel area in cooperation with 

the California Coastal Conservancy, the California State Waters 

Mapping Program, the California Geological Survey, the Minerals 

Management Service (MMS), Monterey Bay Aquarium Research 

Institute (MBARI), NOAA National Marine Sanctuaries, and numerous local stakeholders. Mapping supports an important action item 

and from Point Conception east to the Hueneme submarine canyon. 

This dynamic landscape, characterized by diverse ecosystems and 

both urban and rural populations, faces increasing environmental 

stress due to development, climate change, and natural hazards. 

The USGS has a long history of work in this area, providing information on a range of coastal-zone-management issues to local, 

State, and Federal stakeholders. Agencies of the U.S. Department 

of Interior have specific land- and natural-resource-management 

responsibilities in the Santa Barbara Channel associated with 

the Channel Islands National Park 

(National Park Service), petroleum 

production and infrastructure in Federal 

waters (Minerals Management Service), 

and endangered species recovery (Fish 

and Wildlife Service). The Santa Barbara 

Channel is also the location of the Channel 

Islands National Marine Sanctuary and other 

important marine protected areas. 

of the West Coast Governors’ Agreement on Ocean Health and will 

result in products that address many coastal-zone-management 

issues, including fisheries management, designation of marine 

protected areas, sediment management and coastal erosion, sediment and contaminant movement, earthquake and tsunami hazards, 

impacts of dam removal, documentation of natural oil and gas 

seeps, and evaluation of sites for offshore infrastructure.
Natural Hazards

U.S. Geological Survey scientists 

aboard the RV Melville deploying the 

“Chirp,” a tool for mapping earthquake faults below the seafloor.

Satellite view of the 2003 wildfires 

in southern California. The Santa 

Barbara Channel coast and Channel 

Islands are visible through the smoke 

near the center of the image. 

Both onshore and offshore 

landscapes in the Santa Barbara 

Channel area are geologically 

active, variably characterized by 

rapid uplift or subsidence, cut by 

active faults capable of generating powerful earthquakes, and 

subject to rapid erosion, including large-scale landsliding. 

Climate Variability and Change

View of the geologically 

uplifted marine terraces 

on Santa Rosa Island in the 

Santa Barbara Channel.

Sooty Shearwaters are the most 

abundant seabird in California 

waters during the spring and summer and are an excellent “sentinel 

species” for tracking variability 

in the biologic productivity of 

coastal ocean areas. 

Severe coastal erosion in Isla Vista, adjacent to 

the University of California, Santa Barbara.

Forecasting the Ecosystem Impacts of Climate Change

Potential changes in ocean temperature, upwelling, and ocean currents 

are likely to affect nutrient supply to marine food webs composed of 

diverse and abundant phytoplankton, zooplankton, fishes, seabirds, 

and marine mammals. Seabirds are excellent indicators of changes in 

marine ecosystems and ecosystem health. They are abundant and have 

impacts of winter storms, wildfires, and land use on slope failures 

and identify landslide-prone coastal terrane.

Wildfires

The USGS continues to document the influence of increasingly common wildfires on landscapes and ecosystems in coastal 

watersheds. Sampling and analysis of sediment and fire-related 

contaminants coming out of the Santa Clara and Ventura Rivers 

after the 2003 wildfires has provided important information about 

the potential impact of fires on the sensitive nearshore environment 

of the Santa Barbara Channel.

Climate change will affect humans and ecosystems in the Santa Barbara Channel. 

Understanding past natural changes is key to forecasting the effects of climate change.

Sea-Level Rise, Coastal Erosion, and Inundation

In the coming decades, sea-level rise will likely result in increased coastal erosion and beach loss, 

more frequent coastal flooding from winter storms, wetland loss and degradation, and associated 

negative impacts on nearshore marine and adjacent terrestrial ecosystems. The USGS has established a baseline coastal bathymetric grid and has documented coastal oceanographic processes 

and sediment transport from Goleta to Ventura for use in modeling and forecasting future coastal 

change and inundation from massive winter storms and sea-level rise. Results from these efforts 

are essential for planning and minimizing risk to coastal communities.

diversified to use a variety of niches 

within marine ecosystems, and their 

health and behavior provide crucial 

information about lower levels in the 

food chain. USGS studies of “sentinel species,” such as the Cassin’s 

Auklet and Sooty Shearwater, focus 

on the seabird’s use of nearshore 

habitat, which is affected by climatedriven variability in the abundance 

of their prey. Studies are designed 

to measure breeding success, diet, 

habitat connections, and population 

trends, and to support restoration 

of important seabird colonies in the 

Channel Islands National Park.

Paleoclimate Studies

The USGS is studying the effects of climate change and variability on geologically recent landscape evolution in Channel Islands 

National Park. Most sand dunes that mantle the Channel Islands 

originated from the now-submerged shelves of the islands, which 

were exposed during glacial periods when sea level was about 

300 feet lower than at present. High sea-level stands between 

glacial periods are recorded by emergent, geologically uplifted 

marine terraces containing fossil mollusks with shells that record a 

much warmer 

period about 

120,000 years 

ago—a period 

that may be 

similar to those 

resulting from 

future climate 

change.

Earthquakes

Active faults in the Santa Barbara Channel can generate earthquakes as powerful as magnitude 7 or greater. The USGS is 

documenting the locations, geometry, and slip rates of all the major 

earthquake faults in this area, information essential for seismichazard assessment and mitigation. 

Landslides

USGS mapping and age dating of the Goleta slide and other offshore landslides provide information for evaluating potential 

sources of local tsunamis that could affect the Santa Barbara 

Channel coast. Onshore investigations and mapping document the 

View of the January 2005 landslide 

that struck the community of La 

Conchita in coastal Ventura County, 

killing 10 people and destroying or 

seriously damaging 36 houses.
Understanding Ecosystems

Energy and Minerals

Sand and Beaches

In the face of coastal erosion, sand and 

sediment are increasingly regarded as valuable mineral commodities. USGS work 

on coastal processes is providing detailed 

information on how sand along the Santa 

Barbara Channel coastline is moving offshore and onshore as well as eastward 

along the coast. USGS offshore mapping 

also shows the location and thickness of 

offshore sand deposits. These data are 

Sea otters are considered a “sentinel 

species” that can provide advance 

warning of environmental degradation.

It is increasingly important to understand the ecological, economic, and cultural value of marine 

ecosystems. For example, California’s Marine 

Life Protection Act requires that the best available scientific information be used to evaluate and 

design the State’s marine protected areas to be 

effective in ensuring the future of crucial marine 

ecosystems. It is important to understand how 

potential changes in ocean temperature, upwelling, and ocean currents will likely affect marine 

food webs, from the phytoplankton communities 

at their bases to upper-level predators such as 

fishes, seabirds, and marine mammals. 

The endangered Snowy Plover.

Endangered Snowy Plover Recovery

The western Snowy Plover breeding season 

coincides with the busy beach season in the 

Santa Barbara Channel. A comparison of 

public beaches on the mainland with remote 

beaches on the Channel Islands shows that 

humans frequently disturb Snowy Plovers. 

By observing the distribution and behavior 

of humans and plovers, USGS scientists and 

their cooperators developed a management 

Sea Otter Health

USGS work shows that sea otters living 

in the Santa Barbara Channel risk higher 

exposure to disease-causing parasites as a 

consequence of the food they eat and where 

they feed. Diet specialization, depleted 

food resources, and high rates of infectious 

disease may be acting together to limit the 

recovery of sea otters, considered a “sentinel 

species” that can provide advance warning 

of environmental degradation.

Parasites in Food Webs

Ecosystem-based management requires an 

understanding of ecological networks composed of food webs and habitat dependencies. 

USGS work in Carpinteria salt marsh shows 

that understanding of infectious organisms in 

food webs is inadequate. Parasites dominate 

food web links, can serve as food sources, and 

constitute more biomass than do top predators. This work is now expanding to other 

habitats in the Santa Barbara Channel.

model to maximize protection 

of plovers and 

minimize inconvenience to 

people. After 

establishing a 

small protected area at the core of the Snowy 

Plover roost, disturbance was reduced, plover 

numbers increased, and plovers bred successfully for the first time in three decades.

To better understand coastal processes in the Santa Barbara Channel, 

U.S. Geological Survey scientists 

map and monitor the topography and 

bathymetry of the beach and the 

nearshore seafloor using all-terrain 

vehicles and personal watercraft.

being used to develop models of sediment 

transport and coastal evolution that will 

help guide many coastal-zone-management 

efforts, such as beach nourishment.

Submarine Canyons

Submarine canyons are the conduits for 

moving sediment from the coast down to 

the deep sea. Hueneme Canyon, located at 

the east end of the Santa Barbara Channel 

(see map) extends almost to the shoreline 

and intercepts sand moving alongshore. The 

USGS has deployed oceanographic instruments in the canyon and on its margins to 

better understand regional sediment budgets, sediment transport into and down the 

canyon, and canyon stability. It is especially 

important to understand how the canyon 

head might change given projected sealevel rise and possible changes in human 

practices (for example, harbor dredging) in 

the adjacent coastal zone.

Ecosystem Responses to Fishing in the 

Channel Islands

USGS analyses of long-term National Park Service data on reef communities from the 

Channel Islands have shown that fishing can have important indirect effects on ecosystems. For example, lobster overfishing in unprotected areas has led to increased sea urchin 

populations, resulting in overgrazed kelp forests that have weakened resistance to storms. 

Recovering lobster populations prey on sea urchins and thus can aid the return of kelp.

Kelp forests in the Santa Barbara Channel 

are rich and complex ecosystems.
For more information contact:

Samuel Y. Johnson

USGS Pacific Science Center

400 Natural Bridges Drive 

Santa Cruz, CA 95060

(831) 427-4746

sjohnson@usgs.gov

This Fact Sheet and any updates to it 

are available on line at: 

http://pubs.usgs.gov/fs/2009/3077/

Natural Oil and Gas Seepages

Tar and oil residues are common on California beaches, especially in the Santa Barbara Channel, where natural oil seeps 

abound on the seafloor. The USGS is working with the MMS 

and the University of California, Santa Barbara (UCSB) to 

document the locations of seeps, geochemically fingerprint oil 

from the seeps, measure seepage rates, and predict transport 

pathways of oil from seep sources to the coastline. The geochemical database is being used statewide to understand the 

sources, movement, and fate of oil derived from natural seeps, 

and to distinguish these oils from man-made spills.

Brown sediment plume 

at the mouth 

of the Santa 

Clara River 

following a 

large storm 

event. 

Sampling for groundwater nutrients and 

submarine groundwater tracers from a 

temporary piezometer (small water well) 

on Santa Barbara’s West Beach.

In the Santa Barbara 

Channel “tar whips” 

extrude from natural oil 

seeps on the seafloor, 

extending in length and 

gaining buoyancy until 

they break off and float 

to the surface. Inset 

shows a tar whip” floating on the sea surface.

Water Management and Resources and Public Health

Beach Health

Beaches are popular with humans and provide crucial animal habitat, but beach closures and warnings due to high bacterial levels are 

becoming increasingly common. To address this problem in Santa 

Barbara, the USGS used genetic, chemical, and optical techniques 

to distinguish between different sources of bacterial contamination, such as storm drains, leaking sewers, discharge from urban 

streams, and the resident shorebird population. Determining the 

source of such pollution is essential for defining effective mitigation strategies.

Coastal Watersheds

Winter storms in coastal watersheds move a large amount of water, 

sediment, and contaminants into the coastal zone. The USGS is 

studying the impacts of such storms and the processes through which 

sediment is dispersed from the Santa Clara and Ventura Rivers into 

the marine environment of the Santa Barbara Channel. The USGS 

also plans to study the effects on the coast and watershed of removal 

of the Matilija Dam on the Ventura River (expected in the next few 

years) to develop a framework for science-based forecasts of damremoval effects in other areas.

Submarine Groundwater Discharge

Given the steep topography along the south flank of the Santa Ynez 

Mountains, diffuse submarine groundwater discharge may provide 

nearshore coastal waters with a sustained influx of nutrients, bacteria, and trace elements that can contain pollutants and may play 

a significant role in the development of algal blooms. The USGS 

has deployed a suite of seepage meters, electrical-resistivity senMore information on USGS activities in the 

Santa Barbara Channel can be found at http://

walrus.wr.usgs.gov/research/sbchannel.html. 

The USGS is the Nation’s largest water, earth, 

and biological science and civilian mapping 

agency. USGS serves the Nation by providing 

reliable scientific information to describe 

and understand the Earth; to minimize loss 

of life and property from natural disasters; to 

manage water, biological, energy, and mineral 

resources; and to enhance and to protect our 

quality of life.

sors, and such geochemical 

tracers as radon and radium 

isotopes to better understand 

this submarine groundwater 

discharge and its environmental significance.