Robert Street Dam Removal - Restoring Migratory Fish Passage on the Raritan River, New Jersey

摘要

The Robert Street Dam was successfully removed from the Raritan River in central New Jersey to restore migratory (anadromous) fish passage. This reconstructed concrete gravity dam had a structural height of approximately 7.5 feet, a crest length of 255 feet with a width of 23 feet, which included a 17.5-foot wide rock-backfilled section between two parallel rows of waler-supported steel sheet piles driven into bedrock that encased the original circa 1915 dam. To remove the dam, numerous technical and permitting challenges had to be resolved, including inadequate bridge load capacity that precluded heavy equipment access to the site. Technical obstacles that were overcome during the dam removal included managing the work around frequent upriver reservoir releases, the laborious extraction of over 300 individual sheet piles using two different hydraulic vibratory driver/extractors, and conveyance of over 700 tons of concrete and 70 tons of steel offsite over the five-week removal period.