Mapping of barriers and statistical prediction of their passability is now fairly complete in the Great Lakes basin, yet field assessments of barrier characteristics and passability to migratory fishes are spotty. We will use the Lake Michigan basin as a pilot area for comprehensive field assessment of dam condition, dimensions, and passage technologies. These characteristics will be incorporated into our barrier database, enabling improved estimates of removal costs, watershed cumulative passability, and infrastructure maintenance challenges. In parallel, we will conduct field assessments of passability to spring migrations of Great Lakes fishes in 15 Wisconsin watersheds. Recording the upstream limits of migrations in each watershed will be used to ground-truth our predictive models of the individual and cumulative passability of culverts, thereby validating the broad application of these models. Focusing on Lake Michigan will make both of these efforts feasible during a one-year period, providing a model that can be replicated elsewhere in the basin to further improve barrier databases and decision support tools for connectivity restoration and sea lamprey control.
