I've always found it ironic that clean water has to be shipped to flood sites. Flood water is undrinkable, usually because of microorganisms. As the polar ice caps melt and weather patterns become more erratic, flooding will become a bigger and bigger problem.
In flooded areas, release floating
water filter "robots". The bot floats along on an air filled pontoon, collecting and filtering water. It stores the collected water in the pontoon, so when a bot can filter no more it sinks to the bottom.
Each bot could have a nofilter mechanism that is easy to activate, with instructions on how to use laid out in easy to read pictograms. Also each bot could have a radio beacon.
Next time El Salvador, Missippi, Mexico or wherever floods,
thousands of these things can be dropped in to deluged areas by air. If a person is caught in the water, they can deactivate the filtering mechanism and stay afloat. If no one does, when things are cleared, there will be thousands of gallons of clean water. Both flood victims and water deposits will be easy to find thanks to the radio beacons.