Retention pond considered
WORTHINGTON -- Storm water flowing into Lake Okabena from the northwest may soon be carrying less sediment if Minnesota West Community and Technical College receives funding approval for construction of a storm water retention pond on the Worthington campus.
Jeff Harms, facilities director for the college, has been working for nearly six years on a concept for a pond to capture water from the Worthington campus, contain it to allow for the sediment to settle and then discharge it into the lake. The water now flows across the campus and into a ditch system that carries it through a culvert under West Lake Avenue and directly into Lake Okabena.
Harms said initial plans were to create a holding pond of approximately one-half acre to serve the 40-acre campus, but he has since asked engineering firm Short Elliott Hendrickson (SEH) Inc. to consider a pond that would collect water from a nearby drainage ditch.
While the college continues to seek partners to help fund the project, SEH engineer Steven Robinson said the pond could potentially triple in size and serve an additional 70-plus acres of land along the drainage system.
"There's a ditch along County Road 10 that goes past The Meadows and the ball fields, and it diverts across the south side of the campus," said Robinson. "The pond that we were designing for Minnesota West did not capture that drainage."
The regional pond would cover roughly 65,000 square feet of area and have a depth of 9 feet, though it would be designed to have a maximum water depth of 4 feet, said Robinson. The actual design and location of the pond has yet to be identified, though Robinson said the college is looking at an area to the south of its existing ball diamonds, near Sundown Drive.
The college is willing to provide the land for the larger structure if there is financial support from other entities.
Potential partners include The Meadows developer Ecumen, Worthington Middle School and Worthington Area YMCA, all of which contribute to the storm water runoff.
"Since the expansion of the assisted living center, we've noticed increased flows from that property coming down our north waterway," said Harms. He has yet to make a formal request to any of those entities for buy-in in the storm water pond.
Funding requests have been presented, however, to the E.O. Olson Trust and the Okabena-Ocheda Watershed District (OOWD). The E.O. Olson board will likely meet in the next couple of weeks to take action on the request, while the OOWD board set aside $10,000 for the project, according to watershed district administrator Dan Livdahl. The board took action on the request during its meeting last week, setting aside $5,000 of its cost-share budget for both 2011 and 2012.
Construction costs for a regional storm water pond are estimated at $250,000 to $300,000, according to Robinson -- double or more what Minnesota West would have paid for a pond to handle drainage for just its 40-acre campus.
Mayor Alan Oberloh, who chairs the E.O. Olson Trust board, said he likes the idea of a regional pond and being able to capture runoff from more than 110 acres of land on the city's northwest area before it flows into the lake.
"I'm all for it," he said.
Livdahl said his board thinks the regional pond is a great project.
"It's going to trap sediment and nutrients in the pond," he said. "We hope that between the two, it will improve water quality in Lake Okabena."
Still, Livdahl cautions the public likely won't see a big improvement in the lake's water quality.
"There's a lot of water that flows into Lake Okabena and this is just a small part of it," he said. "(This is) one of many steps that need to be taken to improve Lake Okabena."
If the college is successful in securing funding partners for a regional pond, Harms is hopeful the project can begin this fall.
"We're committed to at least doing our campus pond, but it makes sense not to let the rest of the water bypass it and go into the lake," said Harms.
His $130,000 request from the Minnesota State Colleges and Universities System (MnSCU) may be enhanced if the project is approached as a community collaboration.
"By doing projects cooperatively or with other partners, that tends to move (Minnesota West's) projects up on their priority list," said Robinson. "They've wanted to address this drainage swale that comes off of County Road 10 for some time."
The campus does not have any storm water ponds in place at this time, and was not required to have one because its building projects have been phased in over time. State guidelines for storm water state that a pond must be constructed when a development (buildings and paved surfaces) exceeds one acre of impervious area -- except in situations where the developer has a master plan for the site. The college does have a master plan, and is therefore in compliance.
Right now, the storm water pond project is on Minnesota West's priority list for funding, though it is not at the top. Harms said renovation of the campus field house continues to be their main capital project and highest priority.