I've seen a few amazing scenarios where the people turned it into a real plus:
Garage - They were 3' above flood level. Back basement wall restructured for 2-car garage door (for winter only), yard was graded down & toward the river, driveway & boat launch were installed, all windows were left open until winter, ceiling super insulated, vapor barrier, fire resistant fiberglass faced drywall covered with cement board & old garage torn down with slab remaining as new patio.
Indoor Pool - They were 15' above flood level, a lot of foundation work & then same ceiling treatment as the garage above.
Winter Boat Storage Rental - They were 6' above flood level. Took floor down to river flood level for ceiling height, foundation work, boat launch, connecting pavement, major sump pump system, security gates.
Summer Private Park Rental - They were about 3' above flood level. Tree & stump removal, picture taking large gazebo, volleyball nets, small baseball/kickball diamond with backstop, rolling picnic tables & large bathrooms in basement, party could rush into fully cemented, lighted & painted basement if weather happened since tables & all were out.
Outdoor Café & Boat-up Concession Stand - They were at flood level. Collapsible little buildings, bank hugging narrow floating dock, stair for walk-down bathrooms, bathrooms, electrical to river edge, gravel parking lot, outdoor lighting & signage.
I probably left out a few things, but some fabulous stuff along a fairly unappealing brown river.