Series of 5 locks that provide over fifty feet of lift on the Fox River
After the Portage Canal was opened to connect the Fox and Wisconsin Rivers, it was possible to go from the Green Bay to the Gulf of Mexico. That navigation was made possible on the Lower Fox with the building of 17 lift locks and 2 guard locks between Menasha and De Pere. Lift locks physically carry watercraft between levels and guard locks (located in Combined Locks and Kaukauna) close the flow of water into the navigation channels when repairs are required.
The canal at Portage, between the Fox and Wisconsin Rivers, closed in 1951. The locks in the Upper Fox then fell into disuse. In the 1970s, the locks on the Lower Fox were falling into disuse and disrepair. The locks were closed in 1983 and in 1988, the lock at Rapide Croche was sealed to prevent Aquatic Invasive Species (AIS) from entering the Lake Winnebago ecosystem.
Ownership and operation of the locks on the Lower Fox were transferred from the U.S. Army Corps of Engineers to the State of Wisconsin in 2004, although the COE continues to operate the dams.
Under the guidance of the Fox River Navigational System Authority, the locks on the Lower Fox are being restored and returned to operational status. Some are in use now, and eventually, recreational mariners should be able to navigate the Fox River from Rapide Croche to Lake Winnebago by 2017.
As of this writing (May 2015) the five locks in Kaukauna are closed for rebuilding. Lock #1 and Lock #5 are under construction and scheduled for completion by 2017.
Update: The Kaukauna Locks were symbolically flooded on August 25, 2015 although the entire system is still not fully navigational.