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Is Lehi at risk for runoff flood?

PROVO — Three cities are developing on the benches near Point of the Mountain without proper consideration of drainage and are putting Lehi homes at risk of being flooded, according to the North Utah County Water Conservancy District.

Members of the district's board of directors asked Tuesday for help from the Utah County Commission in dealing with drainage concerns created by developments in Highland and Alpine in Utah County, as well as those in Draper that have crossed over the ridge.

The water district contends that those cities are relying too much on drainage areas designed to alleviate flooding and high runoff, particularly the Dry Creek basin.

"What we're finding more and more is, as development is taking place in both the Draper area and the Alpine and Highland area, that basin is being used by developments as their detention or retention pond," said Frank Mills, a member of the water district's board of directors.

As more houses are built, more water flows into Dry Creek and then down into a retention basin designed to handle historical runoff, said Mills, who also is Pleasant Grove city administrator.

"We're finding water in there 12 months out of the year," he said. "That basin is designed to have water come into it and flow out, not to have water back up behind it."

And that could cause problems when the basin is needed to handle heavy spring mountain runoff, Mills said. Add to that the silting coming from the developments above Dry Creek and north Utah County could see a repeat of 1983, he said.

"(In spring 1983), we had a heavy rain on frozen ground and there was massive flooding in the north end (of Utah County) coming off those dry farms," Mills said. "We're in that situation right now."

Development taking place on the benches — pavement, curbs, gutters, sidewalks and rooftops — is serving as frozen ground, he said.

"If we have in the early spring the water backed up like we did this year and then have a storm event like that, Lehi city and the unincorporated area below Lehi city down to (Utah Lake), they're going to be under water," Mills said.

The North Utah County Water Conservancy District has sent letters to Highland, Alpine and Draper city officials to make them aware of the potential problems. The district is requesting meetings with city officials to discuss possible solutions, said Van Burgess, chairman of the district's board of directors.

But city officials don't seem to think there's much of a problem, Burgess said.

"The cities seem to think they're taking care of it," he said, "but I think we're just sitting on a big problem in the future."

Water quality is also an issue, said board member Kent Evans.

"Who's going to monitor the quality of the water that's being dumped into (the Dry Creek basin) that ends up in the Jordan River and then in Salt Lake City and run through the water-purification plant?" Evans asked.

One possible solution to both water quantity and quality, he said, would be to reroute the water directly west to Thanksgiving Point and dump into the Jordan River rather than following its current southwest flow through Lehi and Highland before reaching the Jordan River.

Evans requested that the county conduct a feasibility study into such a change.

"What we're concerned about is the responsibility we have of controlling those debris basins which were constructed primarily for flood runoff," he said. "When you build these houses, these parking lots and these roofs, you're going to have an additional amount of water running off. We're trying to find a solution to handle that water and send it someplace, rather than down through a community."

The water district also asked the county's help in determining what can be considered "historical runoff."

"Draper city is looking at one set of standards, Highland is looking at another set of standards," said John Jacobs, a North Utah County Water Conservancy District representative.

Commissioner Larry Ellertson said the water conservancy district had the county's support and offered to meet with city leaders and "encourage them to make a more proactive stance in dealing with the problem."

Commissioner Jerry Grover said last year he proposed to mayors of Utah County cities that a Dry Creek management and planning group be created and criteria for runoff be established.

"It got very chilly," Grover said. "They said there's nothing going (into Dry Creek) that's not historical flow."

With the election of new mayors in Alpine and Highland, January may be a good time to revisit the idea, Grover said.

Still, the county doesn't have any authority to tell cities how they can develop, he said.

"The county has authority to go into a municipality and clean out waterways, stuff like that," Grover said. "But we don't have the power to restrict approval of anything. We are going to have to get the cities to go along with it."