Fish passageways allow shad and other anadromous fish to pass over dams and reach their upstream spawning grounds. There are five major fish passageway designs used in the Chesapeake Bay watershed: denil, steeppass, vertical slot, pool and weir, and fish lifts.

Dams block shad and other anadromous fish from reaching their upstream spawning grounds. Historically, most shad and river herring spawned in freshwater areas that are now upstream of dams, road culverts and other blockages.

Fish passage is the ability of fish to migrate up rivers, streams and other waterways, often to access spawning or rearing areas. Barriers to fish passage (which can include road culverts, dams, dikes and other obstructions) can reduce the distribution and habitat available to anadromous fish and, in some cases, eliminate fish populations altogether.