New Digital Images of Humboldt Bay and Eel River Estuary Available

February 8, 2011

Contact: Christina S. Johnson, csjohnson@ucsd.edu, 858-822-5334

New full-color, digital aerial photographs and benthic habitat maps of Humboldt Bay and Eel River Estuary are now publicly available through California Sea Grant and NOAA Coastal Services Center's Digital Coast.

The images, all orthorectified and GIS-compatible, provide the first detailed (.5-meter resolution) inventory of the region's intertidal and subtidal bottom habitats, such as tidal mud flats, salt marshes and eel grass meadows. 

“High-quality, baseline information on the bay’s habitats is something we’ve never had before,” says Susan Schlosser, the project’s leader and a marine advisor with California Sea Grant. ”With it we can monitor habitat trends and changes, adapting our management strategies with different scenarios and conditions in mind.” 

The imagery was collected with the goal of furthering ecosystem-based management of the bay, while addressing specific topics of interest such as endangered species conservation, non-native species control, wetlands restoration and climate change adaptation, as part of the Humboldt Bay Initiative.

Aerial image of Humboldt Bay and Eel River Estuar

Aerial image of Humboldt Bay and Eel River Estuary taken by Photo Science on June 27, 2009. For orthorectified versions of these images, contact California Sea Grant’s Susan Schlosser. (Click to see larger image.)

Aerial image of Humboldt Bay and Eel River Estuary with bottom habitats delineated

The same image as above with bottom habitats delineated. Note that CMECS is the acronym for the national habitat classification system known as the Coastal and Marine Ecological Classification Standard. These GIS-compatible maps are available through NOAA Coastal Services Center’s Digital Coast. (Click to see larger image.)

“In the restoration work we do, the aerial photo images will be a big help during planning and design,” says Darren Mierau, a fisheries biologist with the environmental consulting firm McBain and Trush in Arcata. ”We can use the imagery to help model different restoration approaches, which helps with making the best decisions.”

“Already, the imagery and our work in the field have shown that Spartina densiflora (an invasive grass) is expanding onto some mudflats, which is not good for migratory shorebirds,” says Paula Golightly, a biologist with the U.S. Fish and Wildlife Service, who works with private landowners to restore species habitat. “We’ll be mapping and monitoring that development, because it can help us decide whether to eradicate the plants or try some other strategy.”

The geosciences company Photo Science in Oakland that collected the aerial images on June 27, 2009 waited nearly three years for the requisite weather and tidal conditions. One constraint that made the project such a painstaking process was the need to capture images during an extreme low tide, to expose normally submerged vegetation and substrate. 

The scientists also preferred to have the bay and estuary surveyed in summer when plant growth (biomass) is at, or near, a seasonal maximum. In addition, the photos had to be taken in the morning and with clear skies and calm winds (no small feat in fog-socked Humboldt). 

For their effort, Photo Science won a 2010 MAPPS Geospatial Products and Services Excellence Award in the Airborne and Satellite Data Acquisition category.

The very large files that contain the series of aerial photographs of Humboldt Bay and Eel River are available from California Sea Grant (contact below). 

The benthic habitat maps can be downloaded at the NOAA Coastal Services Center's Digital Coast.

These maps are formatted as a GIS “layer” and require ArcGIS to be manipulated. A free ArcReader, which allows viewing of GIS images, can also be downloaded.

Funding for the mapping project was provided by NOAA Coastal Services Center, in partnership with California Sea Grant, California Coastal Conservancy, Humboldt Bay Harbor District and the National Weather Service Forecast Office in Eureka.