Related Clues:

• Mother
• Hoover ___
• Basin blocker
• Congest
• Sabot
• Fort Peck ___, in Montana
• Water container?
• Spill checker?
• Plumber's challenge
• Gatehouse site
• It can hold its water
• Lake maker, perhaps
• Block, in a way
• Flood preventer
• Hoover or Tarbela, e.g.