The highway was closed Monday afternoon after a section along the Blackwater Bend of the Anchor River near Mile 160 became submerged with about a foot of water, said Carl High, superintendent for the Kenai Peninsula District Department of Transportation.
"We had some flooding initially due to ice jams, but those have broken up and flushed out. Now we have higher than normal runoff in the tributaries," High said.
A 150-foot-long section of pavement was damaged by the overflowing river, but damage was mostly on the shoulders. Crews will likely repair it the summer.
High and Paul Janke, a regional hydrologist for the department, said they have been working for several years to fix that area of the road, reinforcing the banks and controlling erosion problems. Environmental permits have delayed the project, Janke said. "Hopefully (the flood) will reinforce our position," High said.
High said the river be monitored throughout this week. If the river floods again, he said drivers should stay away and use the Old Sterling Highway detour. While the water levels might not look dangerous, the water could erode material from under the pavement. In addition, there is a danger of hydroplaning, and water levels on the river have fluctuated dramatically in recent days, he said.
"The whole Anchor River drainage is at risk with the runoff this year," High said.