The Boise River continues to flow above flood stage. The Ada County Highway District is preparing for the chance flood water could spill onto roadways.
"For the last several weeks we've been working with other agencies here in the valley to plan detour routes should the need to close the roads come about," Nicole DuBois, ACHD public information specialist, said.
DuBois said Eagle and Linder Roads are the most likely to be affected by flooding.
Ada County Emergency Management Director Doug Hardman said the river flow is expected to increase to 8600 CFS by Wednesday night. Emergency management crews aren't anticipating any more major issues to arise at that level.
"What can change all that is for one major tree to topple, maybe land against a bridge or pull out a large piece of embankment, and that changes things," Hardman said.
Hardman said the best advice now for city managers and residents is to be prepared.
"If the bridges close, and maybe we don't have any utilities, it could be a long-term evacuation," he said. "It could be something that lasts multiple weeks. It wouldn't be just a few days. That's kind of a worst-case scenario, but it's always best to plan for the worst."