The flood resulting from Tuesday's breach of Kaloko Reservoir traveled as rapidly as 20 mph and reached Kuhio Highway within 16 minutes of the dam failure, according to a University of California-Irvine engineer.

"There was very little time to react, even if people had had a warning," said Brett Sanders, an associate professor of civil and environmental engineering.

Sanders worked on the Kaloko flood with researchers Lorenzo Begnudelli and Stephen Esaki, a Kaua'i native. They study the computer simulation of water movement in rivers, estuaries and coastal waters, including tsunamis moving toward land as well as downstream movements like floods.

The computer model showed that as the water roared through the steep valley immediately below the reservoir, it was 20 feet deep and moving at 15 to 20 mph. Where the land flattens out, the flood broadened, thinned to a 10-foot depth and slowed to 5 to 10 mph. After it crossed Kuhio Highway and where the valley narrows again, it would have once again picked up speed and depth, he said.

The Sanders team's graphic representations and animations of the path and movement of the water are available online at: http://gram.eng.uci.edu/~bfs/model_in formation.html.

They used 10-meter (33-foot) resolution U.S. Geological Survey maps to create a computerized image of the Wailapa Stream valley and other terrain below Kaloko Reservoir.

Then, applying the amount of water behind the dam, the width of the dam breach and other information, the Sanders team simulated how the muddy water would have moved down into populated areas.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.