Yahara River flows through Madison to connect Lake Mentota to Lake Monona--and further to the south to lakes Waubesa and Kegonsa. A series of locks at Tenney Park on the city's near east side allows boats to travel from one lake to another. The City of Madison operates Tenney Park Locks during the summer season.

In 1848 a sawmill, gristmill and brewery were located where the Tenney Locks are today. They used an earthen dam for power. The city replaced the dam with the first locks built on the site in 1896. In 1904, a waterway was completed by digging the Yahara River deeper between Lake Mendota and Lake Monona. This was done to get rid of swampy land between the two lakes. The locks have been rebuilt many times since then.