The storm water that runs off Dodd Road soon will be sprinkling down on the ball fields at King Park.

The city of Lakeville and the Vermillion River Watershed Joint Powers Organization have teamed up on a pilot project to reuse the water that collects in a triangular pond at the park to irrigate up to two fields.

"There's more and more pressure on groundwater all the time because of the growth in the metro area," said Lakeville City Administrator Steve Mielke. "The idea here is to demonstrate a different use of storm water that's also good for the environment."

The irrigation system, to be installed at one or two fields, depending on bids received, will be the first for the diamonds at King Park. The city previously brought in a portable irrigation system that was hooked up to city water when the fields needed a drink. The pond-fed system would be ready for use next spring if installed according to plan this fall.

Mark Zabel, an administrator of the Vermillion River Watershed group, said golf courses have long used irrigation systems that draw from ponds.

"We're kind of hoping that this demonstration expands beyond just the municipal application for ball fields, that it catches on with townhomes or developments," Zabel said. "We're really trying to dig into that water conservation element."

The watershed organization is paying the largest share of the $62,000 cost to install the irrigation system.

In addition to conserving groundwater, the project will help clean the Vermillion River.

The pond at King Park holds water that eventually ends up in a tributary of the Vermillion, a cold-water trout stream with degraded habitat that local officials have been trying to restore.

The storm water pond can be trouble for the river because it's often warmer than the river -- heating the river water and making it hard on the trout -- and it can carry polluting nitrogen and phosphorus to the stream.

On the fields, however, that same nitrogen and phosphorus will be good for the grass, said Dale Thompson, who supervises municipal storm water programs at the Minnesota Pollution Control Agency.

"People are recognizing that it's a detrimental thing to have too much storm water volume," he said. "They're looking for ways to reuse it and keep it from flowing into streams and rivers."

Thompson said he's had a couple of inquiries from cities about using storm water ponds for irrigation in recent years, and there is certainly plenty of opportunity if the King Park project succeeds.

In Lakeville alone there are about 300 storm water ponds.

"There's all kinds of these ponding basins all over the watershed," said Dakota County Commissioner Joe Harris, who sits on the watershed board. "It certainly is a lot better to utilize natural water to irrigate on the ball fields or people's yards than it is to use city well water."

Katie Humphrey • 952-882-9056