Marine mattress installation continues on Elliott Bay seawall project

At the ongoing construction of the new Elliott Bay seawall in Seattle, marine mattresses are installed in front of the new face panels to create a shallow water corridor for migrating fish.
Marine mattresses are rock-filled containers generally constructed with UV-stabilized co-polymer geogrid materials. Geogrid panels are laced together to form mattress-shaped baskets that are filled with stones similar to the construction of gabions. They are usually filled off-site and installed by lifting into place.

See video from the Seattle seawall project.