The minimum dike height will be different for each and every installation.
The minimum height of the dike will depend on the largest tank, the total contained volume required and the footprint of the containment as well as the volume of any additional tanks.
Additionally, many states in the US require the containment to hold a certain additional volume based on the maximum rainfall for the specific installation area.
Some states simply mandate that you increase the constructed volume to 110% of a calculated value ...