In the early morning darkness, up to their chests in flood waters, Midvale firefighters and public works crews quickly found out what caused storm runoff to pour into four homes Saturday, drowning a family dog.

Wasatch Constructors, the consortium hired to rebuild 17 miles of I-15 in Salt Lake County, had plugged two city drainage lines. That prevented rain water from flowing away from back yards on the east side of the freeway to a culvert on the west side, city officials said."They cut and filled one full of concrete. The other one they just buried," Midvale public works director Kane Loader said of what city workers discovered when they responded to the crisis shortly after 2 a.m.

Ross Mitchell, who lives in one of the four Adams Street homes damaged Saturday, was planning to have a big Final Four party in his basement Monday night. Those plans had to be canceled, although Mitchell did manage to save his big-screen TV.

Water came in through a laundry room door early Saturday and woke a friend of Mitchell's step-daughter who was spending the night in a sleeping bag on the basement floor.

The teens woke Mitchell and his wife, Kim, and the family went next door to awake neighbors.

"I have boxes of clothes I just have to throw away now, and movies of the kids from the 1980s (that were damaged)," Kim Mitchell said. She and her family were at their home today, trying to clean it up.

Ross Mitchell's Suzuki Swift, parked in the back yard, filled with water above the door handles during the flooding. Mitchell said he hasn't tried to start it yet.

Kim Mitchell said flooding of the yard had been occurring since October and she has previously given pictures of the flooding to city and Wasatch Constructors officials.

Blockage of the drainage lines apparently occurred last summer when Wasatch widened a portion of the freeway near the homes, at about 8400 South, so it could temporarily shift traffic from one side of existing I-15 to the other. Loader said designs he was shown over the weekend indicated Wasatch intended to plug one of the lines but wanted to keep the other one open, so water would drain away from the homes.

"I think they missed something on their engineering," he said. "The people there have been calling Wasatch Constructors for two weeks on this problem."

City manager Lee King said Wasatch crews did apparently take a look at the situation days before Saturday's flooding occurred, but took no action. He contacted Utah Department of Transportation deputy director Clint Topham early Monday and was hoping Wasatch would take responsibility.

But Wasatch spokesman Brian Mauldwin said Monday morning it was "too early to say" what caused the problem.

"The case is under investigation," he said, adding that Wasatch had scheduled an internal meeting for 11:30 a.m. Monday. "The number one priority was to assist (Midvale) and get water out of basements and back yards. The rest of the story will be forthcoming as details are flushed out. . . . "

Topham said UDOT purchased liability insurance for itself and the contractor for incidents of this type. If it does turn out to be a problem caused by the contractor, he said, the insurance could be used to pay for damages.

"This is a different situation than loss of business," he said, referring to business owners along the I-15 corridor who have claimed dramatic drops in revenue but have not received financial assistance from UDOT or the contractor.

"We've faced this kind of thing all the time where you have to go back and check and see if there was flooding there before. . . . We need to find out what the problem is and get it fixed."

About 4 feet of water invaded the basement of at least one home. Another home also suffered extensive damage. A smaller amount of water leaked into two other homes.

A dog, confined to the basement of one home, drowned.

Loader said officials don't yet know a damage estimate total but believe it will be in the thousands of dollars.

King said the city let UDOT officials know it was "mightily annoyed" about the incident.

"This is a bad situation for both the residents and for Wasatch Constructors," he said.

King said Wasatch crews did respond around 7 a.m. Saturday and did a good job of helping to pump and drain the area. The consortium also called in a private disaster relief company to help clean the homes, King and Loader said.

"I guess our main problem with Wasatch is they did not respond to us in the middle of the night," Loader said. "I even chased their people down at 4 o'clock in the morning and they said, `Sorry, we can't get any help to you until 7.' Midvale public works and the fire department were on their own trying to fight this thing."