So let me get this straight... ship captains and port users pay fees intended for harbor maintenance which are not, in fact, spent on harbor maintenance because of an arbitrary cap on spending which causes the maintenance fund to grow faster than it is used? Cripes, just spend the harbor maintenance money on maintaining harbors already.
If opponents of this are really worried about overspending due to the arbitrary limits being lifted, maybe find a compromise like defining a formula that prioritizes critical maintenance such as flood control, dredging and channel markers, and simply divide the current fund content up based on that to set new individual port spending limits so it’s impossible to overdraw the fund.