EDITORIAL : WATER PROBLEMS PERSIST; ALREADY-STRESSED RESOURCES MUST BE MANAGED MORE WISELY.

RECENTLY published research suggesting that the Lost Colony of Roanoke in what now is North Carolina was the victim of a severe and persistent drought more than 400 years ago isn't simply intriguing from a historical standpoint. It also is instructive.

The tragic fate of the first English colony in North America is a reminder that water shouldn't be taken for granted. This is especially true in Southern California, a normally semiarid region that's heavily dependent upon imported water supplies - all of which are under stress in one way or another.

This water is brought to the Southland via aqueducts that tap the Owens River system in the eastern Sierra Nevada, the Colorado River and the Sacramento-San Joaquin Delta.

In the case of the High Sierra water, the Los Angeles Department of Water and Power is under pressure to surrender more water for environmental purposes, such as alleviating dust storms in now-dry Owens Lake and replenishing saline Mono Lake.

California for decades has been taking more water than it is legally entitled to from the Colorado River. But one day California will have to surrender some of this water to accommodate growth in Arizona - and no firm plans are in place to replace the water that ultimately will be lost.

Meanwhile, engineers and politicians have yet to resolve conflicts over allocating delta water for environmental use as opposed to urban and agricultural use. Further, pumping water from the low-lying delta into the aqueduct serving the Southland is a tricky operation due to the risk of salty backflows from San Francisco Bay.

What's needed, both for the sake of water quality in the delta and water reliability for the south, is a canal that would tap the Sacramento River upstream. But this logical and decades-old concept continues to infuriate parochial interests in the north, and its fate remains in doubt.

Still, Southern Californians - notwithstanding all these problems - have one advantage over many other areas. Since they obtain water from several widespread sources, they aren't as vulnerable as they might be in event of a drought or some other natural disaster.

Nevertheless, these water resources must be managed more wisely if California is to continue to grow and prosper.

We are convinced that this can be done. But no one should take it for granted that it will be done given the tendency of too many politicians to invest more energy in fighting over water problems than solving them.