Maintenance Survey of a Breakwall

eTrac provides high resolution imagery on breakwalls to help keep them maintained. Breakwalls are often constructed atop moveable material which requires them to be constantly monitored for movement or deterioration due to constant wave action. This imagery provides a detailed look at the complete structure of a breakwall in order to determine if repairs are needed.

Demolition of the East Span of the Bay Bridge

Utilizing positioning equipment installed and supported by eTrac, crews have begun to carefully dismantle nearly 2 miles of the 77-year old East Span of the Bay Bridge section-by-section, in roughly the reverse order of how it was built in the mid-1930s.

Crews will first work in the westward direction toward Yerba Buena Island, taking apart the cantilever section and demolishing the S-Curve, before moving east to dismantle the 504’ and the 288’ truss spans. The demolition team will then head to the waterline to remove the piers, pilings and foundations that support the span. When the entire demolition project is complete, over 58,000 tons of steel and 245,000 tons of concrete will have been removed.

For more information about the project, check out the Bay Bridge website here.

Channel Migration in Dillingham, AK

eTrac assisted the USACE in monitoring the migration of the main channel of the Nushagak River by Dillingham, providing the first full multibeam survey of the area. It appears that the deepest part of the river is getting closer to Dillingham. This is the first in an ongoing series of surveys over the coming years to monitor and address the changes.

Object Detection in the Bay

eTrac performed an object detection survey in the Bay Area where many underwater obstructions were found including a car, multiple boats, and the remnants of a deteriorating pier. Remnants of the pier were visible at low tide, but not during high tide, making the survey more challenging. The high detail of the data that was collected allowed us to identify smaller obstructions, including small skiffs and even objects as small as car tires.

Multibeam Survey of Humboldt Ocean Disposal Site

eTrac completed a multibeam survey of the Humboldt Ocean Disposal site approximately 10 miles offshore. Mulitbeam and snippets data were collected on an R2 2024 down to 400ft to create both bathymetry and backscatter grids. A sediment classification map was created using this data with sediment samples collected across the area.

BEAMS in the Bay

eTrac hosted 8 students from the College of Charleston’s BEAMS (BEnthic Acoustic Mapping and Survey) Program to conduct a survey of Raccoon Strait in the San Francisco Bay. The students were able to learn and assist in the survey set up and acquisition, gaining valuable hands-on experience. Students in the BEAMS program will be able to process and analyze the collected data during future research and independent study projects.

San Francisco Bay Bridge

Multibeam hydrographic surveys have been conducted around a pier of the San Francisco Bay Bridge in preparation for further bridge deconstruction. Multibeam data was acquired using an R2Sonic 2024 coupled with an Applanix POSMV Wavemaster V5 Position and Motion System. Multibeam imagery was used to view possible obstructions in the area. 3D image of the bathymetric terrain and base of a pier of the San Francisco Bay Bridge was processed and visualized using QPS Qloud. 3D anaglyph images were created using custom R2Sonic 3D visualization software.