Possible Clues:

• It can be used the keep floodwater at bay, say
• Grab some grains first to be used as flood protection
• Flood defender on strike, maybe got from ...
• Flood fortification unit
• Common balloon ballast
• Drop round with book, a heavy weight
• Heavy protection that,s used by woman wanting son for husband
• Attack French novelist, getting speaker's gift returned
• It's used to protect against flooding
• Flood barrier builder