Related Clues:

• Blockage
• Beavers' project
• Sandbag stack, maybe
• High ground in Dutch lowlands
• Hold back
• Retainer
• Water gate
• A bank may have one
• Horse's mother
• It may get high marks
• Flood protector
• Fort Peck, for one
• Obstruct
• Beaver's project
• Grand Coulee, e.g.