Historical clue formulations

• Flood preventers — 2025-02-23
• Sights in New Orleans — 2016-07-24
• Cousins of levees — 2016-02-07
• Retainers — 2005-06-26
• Dutch sights — 2003-08-31
• Flood stoppers — 2002-05-12
• Dutch sights — 1999-02-15