Might be worthwhile putting your point forward to a higher authority. Tell them its not just a hole in the ground with water in it, its part of a much bigger system since it has a lot of flow and that the flow rate is important. Maybe if you get enough people behind it the government will put the needed funds into it. It might be wishful thinking but its dead in the water if no one asks in the first place. Put it to them as more than just a dive site. Dont even mention that it may help. Get geologists and water management people on board to give it credability. If it all ends with only 2 divers being able to dive it one weekend a month then thats 2 more than are doing it now.
Matt