DURHAM, N.C. — The threat of rain this weekend is bad news for anyone who may need to travel Interstate 40 in Durham. Because of all the construction, the runoff has nowhere to go and has turned that part of the interstate into a muddy mess.

State environmental experts investigated the situation Friday -- a day after the I-540 bridge work over I-40 became bridge work over troubling water.

Almost three inches of rain fell in less than an hour -- a record for July 29. Muddy water flowed all over I-40.

"I left work around 4:30, came up to 40 to get on 540, and traffic was backed way up when I came up the bridge," driver Glen Lowery said. "You could see a huge puddle of water down on 40, and everybody was having to just about stop to go through it."

All that rushing water came right in between two concrete colums. It was like a waterfall, and all the rushing water knocked over trees right next to the road.

Motorists complained to the Department of Transportation. State engineers met with the contractor, Lane Construction.

DOT officials said Lane installed a new drainage pipe on the south side of 40 that should control future runoff. That made Lowry feel better.

"Yes," he said. "With the construction, if you left it alone, it could cause major traffic jams, plus major accidents, too. If somebody hit that big puddle of water and hydroplaned, they could get killed or kill somebody else."

With rain in the forecast for the weekend, that could put the repair work to the test.