apparently those things cost about $8,300
To hold back 24" of water, ~$19 a foot.
The difficulty in these situations is knowing what size you really need. 36" of water is more than double the price.
We pushed the limits on this one. Friday morning, after it started moving around, Randy called the company and told them we had about 28" of water against it. Their reply "OH, that's not good".
It was why we added all the sandbags and 2x4 bracing. Too much pressure and not enough weight at that point to keep it steady.