I don't see why we need a regulation to give dam owners more time.  The board should be able to solve this problem without a regulation.  The board could choose not to enforce the regulation or it could choose to work out a consent agreement or other enforcement agreement with each owner of each dam not in compliance with the regulations.  Why is a regulation required when regulatory enforcement of the regulations is discretionary?  Why is a regulation necessary when the board and owner could work out a compliance agreement as part of its enforcement powers?
 

If the regulations represent the minimum safety standards to protect life and safety, then I don't understand why it should matter that prior dam owners have spent a lot of money making their dams more safe (but still not safe enough if they don't meet the current regulations that are the MINIMUM standards).