Habitat Restoration in Thunder Bay, Lake Huron

view of barge used for reef construction, with capped CKD pile on shoreline in the background

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Reef Construction

barge crane adding material to a reef during constructiondiver inspecting newly constructed reefbarge used for reef construction in Thunder Bay
Construction details:

Limestone cobble varying in size from 6 to 18 inches (donated by Lafarge) was used to build the reefs. Reefs are located adjacent to the Cement Plant reef and CKD reef; sites where spawning lake trout congregate. The East Reef serves as a reference site and will not be altered.  Different reef configurations allow evaluation of height, size, and orientation as factors that affect spawning and egg survival.

Stage I
– Eight small ‘pilot’ artificial reefs were built in 2010 to begin evaluation of spawning activity.
 Schematic diagram of reef construction
     • each reef is 30 feet in diameter by 9 feet high.
     • Monitoring wells were installed in six reefs to measure water quality within the reef structure

 Stage II – Construction of functional prototype reefs was completed in summer, 2011 
     • 24 reefs, 8’ wide, 75’ long.
     • reefs are either 5' or 10' high, oriented either NW-SE or  NE-SW  
     • one large reef, 300’ long, was added
                                                                                                 Schematic diagram of reef construction
                                                                                                                                                                     (click on image for detailed view)

Map of Thunder Bay and Reef Locations