One of the key advantages of free market economies over strict socialist ones, is the much greater incentive to innovate. NPR has a wonderful case study in free enterprise in this article on the use of new water-filled tubes instead of sandbags to prevent flooding.
NPR’s interview the inventor of the AquaDam and talk about how he came up with the idea (playing with water balloons), how the water-filled dykes work, who are using them, and how much they costs.
The only things that were a little difficult to understand, was the description of the tubes themselves, and the explanation of why they don’t move. The idea is pretty simple, but an image helps.
Note: Minnesota Public Radio also has a good article with pictures.