1. Look to Websites, there a number of them,such as ProEarthdev.com for 2 pages that teach how to use sandbags so they actually work.People really need to understand these facts or sandbags fail! Knowing how is the single most important thing about using sandbags so that they actually do the job! Please, please help people to know how through media or any other way possible.
2. Desparate people in flood situations could do with understanding which 'protection' equipment is good for which job. For example, Water energised bags will only work for a few inches of water. Once water-energised, they weigh the same as water due to what they are filled with. Thus they float! A sandbag in water doesn't move if laid correctly. There are a number of websites that show the best ways to build walls for water diversion. ProEarth shows good ways for property protection, but there are good sites for this too.
3. Community 'flood aware' groups can help FEMA and local government to understand what planning they need to do.