Holmen Public Works Department employees are trying to solve the mystery of why two stormwater detention basins in the Deerwood Estates addition don’t drain.
Dean Olson, HPWD director, told the Holmen Public Works Committee at its Sept. 7 meeting, his department is looking into the basins turned ponds. The detention basins were put in when the subdivision was built in 2006.
“We are planning to see if we can get the water to soak away, when we get it pumped down,” Olson said. “Now, it (stormwater) just sits there. There’s no storage in either basin; we have to do something.”
Olson thinks the reason water doesn’t drain is due to silt.
“It is my opinion the basin does not drain properly because of sediment that has collected on the bottom,” Olson said. “Many times this sediment creates a seal over the sandy soil that prevents the water from soaking away. We are also considering installation of other drainage mechanisms to help that situation, but we want to investigate the first option before making the other changes.”
Olson’s department is planning to haul out a mound of sediment in the eastern basin and do more excavation in the basin this week. After the sediment is cleaned out, the next step will be to establish a layer of grass throughout the basin.
“A grass growth allows water to perc (percolate) appropriately,” Olson said. “Our hope is to remove the sediment and to eventually establish a grass cover that will allow the basin to drain.”
Wastewater treatment plant design
Olson presented information about a change in the design for the village’s new wastewater treatment plant. One change is to add a building in the treatment complex to house blowers.
“The blowers are currently in the lab and are noisy,” Olson said. “We feel as though this is an added advantage to the design.”
Another change in the design would create a stairwell to the pumps, replacing a ladder now providing access to the lower level.
Since deciding to build a WWTP instead of sending its wastewater to La Crosse for processing, the village has contracted Short Elliott Hendrickson Inc. to design the plant at a cost of $538,550.
Before changing plans, the village had been working to “regionalize” its sewage treatment by sending its wastewater to La Crosse’s treatment facility. The Village Board decided to build a new plant in December 2015 after it learned the city of La Crosse would charge the village a $2.2 million hook-up fee.
The new treatment plant is anticipated to cost about $14.5 million; although the exact figure has yet to be determined. The village hopes to begin building the new plant next year.
The village’s current waste treatment plant is 34 years old. The new plant will need to handle a population growth of 15,000.
Holmen Drive construction
The HPWC voted to recommend the Holmen Village Board approve change orders for construction underway on Holmen Drive.
Chippewa Concrete Services Inc., general contractor for the project, submitted a change order to design, furnish and install a retaining wall on the northwest corner of Gaarder Road and Holmen Drive to support an existing power pole at a cost of $10,430.
The contractor also submitted a change order to furnish and install a layer of rock to correct a poor subgrade on the road at a cost of $40,575.
The construction project is scheduled to be finished this fall.