Related Clues:

• River barriers
• Glen Canyon and Grand Coulee, e.g.
• River blockers
• Hydroelectric structures
• Blocks the flow
• Some power producers
• Blocks off
• Creek blocker
• Hydroelectric power projects
• Water barriers
• Beavers make them
• Hoover, etc.
• Broodmares
• Utah's Flaming Gorge et al.
• Moms on all fours