Joe Rydell, northwest district fisheries supervisor for the Nebraska Game and Parks Commission, said these lakes are closed to trailered boats or limited to small boats that are launched by hand:Island Lake at Crescent Lake National Wildlife Refuge,Lake Winters Creek at North Platte National Wildlife Refuge,Smith Lake at Crescent Lake National Wildlife RefugeWhitney Lake Wildlife Management Area. Crescent Lake Wildlife Management Area: The lake has dropped below the concrete ramp and is possibly unusable for trailered boats. Lake Minatare State Recreation Area: Water levels continue to drop, and the low-water rock ramp is the only usable ramp. Smith Lake Wildlife Management Area: The lake is drawn down for an Aquatic Habitat and Angler Access Improvement Project. Walgren Lake State Recreation Area: The lake is extremely low and considered unusable for boats.