A Benthic Habitat Monitoring Approach for Marine and Hydrokinetic Sites

Status

Completed

Principle Investigator Contact Information

Name: Gene Revelas

Description

This project demonstrated a seafloor survey approach for generating detailed benthic habitat maps at MHK sites. The approach combined multibeam bathymetry and acoustic backscatter (multibeam echosounder, MBES) mapping with sediment profile imaging and plan view (SPI–PV) imaging as a rapid, cost-effective benthic habitat mapping protocol, and it can be used at any marine renewable energy site (e.g., offshore wind farms) where benthic impacts are a concern. A primary technical innovation was the development of image processing software that automatically identifies and measures key features in the images. We also designed, built, and tested a power SPI camera system that is effective in sampling firm substrates. This project is part of the DOE Triton Initiative.

Funding Source

U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy

Funding Contact

Yana Shininger

Location of Research

Olympia and Sequim, Washington; Newport, Oregon

Project Aims

It is important to document the physical and biological seabed habitat conditions at MHK and other marine renewable energy sites before, during, and after device deployment. The objective of this project was to design and demonstrate a consistent, repeatable, and semi-automated seafloor survey method for generating broad-scale, high-resolution benthic habitat maps of MHK sites. The approach developed provides cost-effective, contiguous, and high-resolution spatial coverage over broad areas, can be communicated universally, and can be used to inform the siting, permitting, and monitoring needs of regulators, developers, and other stakeholders.

Study Progress

This 3-year project was completed in June 2020. We surveyed and generated detailed benthic habitat maps of three coastal areas, two near Sequim, Washington, and one at the PacWave South Wave Energy Test Site off Newport, Oregon. We developed a computer vision image analysis platform (iSPI) that uses deep learning, neural network algorithms to automatically identify and measure key features in the images, such as grain size, redox depth, biogenic structures, and biota. We also designed, built, and field-tested a prototype power SPI camera that achieves improved penetration in firm substrates.

Key Findings

The focused combination of MBES acoustic and SPI–PV imaging technologies can be used to rapidly (days to weeks) and cost-effectively map broad seafloor areas (tens of square kilometers) and document benthic habitat conditions at a detail level that is suitable to be an effective offshore renewable energy site seabed monitoring tool. The computer-automated image processing system generates consistent and repeatable physical and biologic image data sets that are key to ground-truthing the acoustic survey data. The prototype power SPI camera provides a proof of concept for achieving improved SPI camera prism penetration in firm, sandy substrates but additional resources/work are needed to develop a readily deployable power SPI system.