One of the dominant uses of the Madison area lakes is for boating. In order to develop a long term data set on the temporal fluctuations and trends in such activity, the LTER project has obtained records of boat traffic that passes through the locks at the head of the Yahara River on its stretch between Lake Mendota and Lake Monona. This data was gathered by the Dane County Department of Public Works as part of the County's ongoing monitoring of its own facilities and their use. This data set will be augmented as the Department of Public Works makes updates available. Sampling Frequency: tallied daily April through October; exact starting dates vary each year Number of sites: 1