The thick mud of a river bottom literally stopped contractors in their tracks but with the help of an interlocking composite matting system, their project moved along to completion.
The last time fish migration took place from Centreville’s rivers and streams to the Chesapeake Bay was in the 1800s. But now, thanks, in part, to the temporary roads provided by Mabey Inc., fish migration has been brought back to life.
Maryland’s Department of Natural Resources (DNR) worked on a dam removal project in Centerville to open up new waterways for migrating fish trying to reach Chesapeake Bay tributaries for spawning. Dams like this one, built over 200 years ago, change the local ecosystem and degrade the water quality of the watershed as well as block the migration of several species of fish and aquatic life through the streams, rivers and tributaries of the Chesapeake Bay.
The main concrete portions of the dam were removed and a new channel, approximately 150’ x 3’ wide, had to be dug out for the new water flow to travel. The riverbed was dewatered for weeks but from years of decaying vegetation, the surface was layered in thick, black mud. The contractor drove his excavator onto wooden crane mats but they were no match for the black muck that was several feet deep in some spots. The mats sank, taking the excavator with them. The job stalled.
DNR needed a quick solution so they called on Mabey, an engineering and construction equipment rental company near Baltimore Maryland. Mabey provided their DURA-BASE® composite matting system that joins together with locking pins to create a puzzle-like roadway with varying configurations. The composite mats are impermeable and do not soak up water or sentiment like wooden mats do. And their design allows weight to be distributed evenly throughout the roadway, creating a stable surface for heavy vehicles and equipment.
“The folks at Mabey were crucial in getting this project done right and getting it completed on time for summer planting. We spent over two years gathering data, competing for grants, and preparing design plans for the project. We always try to plan for the unexpected, but were completely caught off guard by how ineffective the wooden crane mats were in the impounded sediments behind the dam. With hardly any lead time at all, Mabey had mats and a friendly crew on site to bail us out,” said Jim Thompson, Fish Passage Coordinator for State of MD, DNR.
Within five days, Mabey’s installation team delivered and installed 140 mats to create a stable roadway through the former impoundment. With the stabilized roadway in place, the contractor was able to drive his excavator out on the roadway to create a new channel. The excavation work was completed in October of 2015. Shortly thereafter, native vegetation was planted around the channel and today the fish are able to migrate through Centerville and back down to the Chesapeake Bay.
For more on this project, go to www.mabey.com/us/projects/fish.