After graduating from Rutgers University, Mario worked for a year as a research hydrologist conducting ground water surveys for the United States Geological Survey on Long Island, New York.

He joined the Geological Survey that year and retired as a senior research hydrologist in 1972.

In 1972 he was appointed research hydrologist at the National Hydrology Research Institute of Environment Canada, a position he held for 17 years; after the institute's move from Ottawa to Saskatoon, he also served as its chief scientist.

"If the past is any indication of the future, we are indeed at a low point," said Thomas Croley, a research hydrologist with the Great Lakes Environmental Research Laboratory in Ann Arbor, Mich.

Before becoming an astronaut in 1987, Commander Runco worked as a research hydrologist for the United States Geological Survey and as a New Jersey State Trooper.

But the thinking was, explained Zoltan Szabo, a research hydrologist with the U.S.G.S, that "only places with a lot of uranium or thorium in the rock would have a problem.

Robert M. Hirsch is research hydrologist and a former Associate Director for Water of the U.S. Geological Survey.

Raymond L. Nace, a research hydrologist and former head of the United States scientific committee for the International Hydrological Decade, died of emphysema March 6 in Boise, Idaho, the United States Geological Survey said yesterday.

Her father, who is retired, was a research hydrologist in Denver with the United States Geological Survey.

The bridegroom, a graduate of Tufts, is now a postdoctoral research hydrologist in Reston, Va., for the water resources division of the United States Geological Survey.