The sagging condition of Hawai'i's dams, most of them built by agricultural companies long before current engineering standards were in place, is not news to the state's engineering and civil defense communities.

What is surprising is that, despite daily monitoring and ongoing routine maintenance, many of these dams are badly in need of repair.

That's the bottom line in a recent story by Karen Blakeman, who reports that 22 of Hawai'i's 130 dams raise serious safety concerns according to standards set by the American Society of Civil Engineers. Fully 20 of those are listed as "high hazard," which means there would be significant loss of life and property if they failed.

Among them is the Nu'uanu Dam, which holds back Nu'uanu Reservoir above heavily developed Nu'uanu Valley. That's under the control of the city Board of Water Supply.

Another is Wahiawa Dam, used by Dole Food Co. as a source of agricultural irrigation water, which poses a threat to Waialua Town.

The renewed focus on dam safety is a direct response to the failure of levees around New Orleans after Hurricane Katrina. Engineers and others had long warned that the levees were not in good enough shape to hold back water in the event of a Category 5 hurricane. And they were right.

So what is to be done here? Rebuilding these old dams to current safety standards would be an expensive and difficult proposition. Dam managers do what they can by keeping water levels relatively low and maintaining a high level of regular inspection.

But sooner or later, it is likely than a dam will fail, either after a particularly vigorous storm or when the old structure simply no longer holds.

When that happens, the economic and human losses that might occur could easily eclipse the costs of repairing or rebuilding the dams today. That's a chance we simply should not be willing to take.

The best approach would be a public-private partnership, in which all concerned parties, including residents who are potentially in harm's way, cooperate on solutions ranging from rebuilding critical dams to diverting water or creating spillover routes to minimize damage in the event of a dam breach.

Not everything can be done at once, of course. Engineers should be encouraged, perhaps with support from the Legislature, to create a priority list of needed repairs, starting with dams that pose the greatest or most immediate danger and working down.

It's time to start somewhere, while focusing on a more comprehensive and thoughtful approach. Otherwise, our piecemeal approach will eventually fail us.