If you’ve headed west out of Stillwater anytime in the past year, you’ve undoubtedly noticed the construction near Manning Ave. and Hwy. 36, where Washington County is working with the Minnesota DOT to construct a new interchange. Traffic has significantly increased on Hwy 36 since the St. Croix Crossing bridge was completed in 2017 and the newly designed intersection at Manning Ave. will include a bridge over Hwy 36, as well as entrance and exit ramps to improve safety for drivers.
Along with these changes, Washington County is also working with the Brown’s Creek Watershed District and Applewood Hills Golf Course to design a stormwater reuse system that will collect runoff from Hwy 36 and Manning Ave. and use it for golf course irrigation. The project will reduce groundwater pumping by 7 million gallons per year and provide 30% of the irrigation needs for Applewood Hills.
“A big project like this – adding a bridge and a number of ramps to access that bridge – adds a lot of new impervious surface,” explains Frank Ticknor, a design engineer with Washington County Public Works. Impervious surfaces include concrete, asphalt, rooftops, and other hard surfaces that rain can not soak into. Any new stormwater runoff from the intersection would ultimately flow into Long Lake.
“Long Lake is impaired for excess nutrients and has flooding concerns,” continues Karen Kill, Administrator for the Brown’s Creek Watershed District., “So, we want to ensure that the new interchange does not create additional problems.”
To counteract the increase in impervious surface, the county is building a series of four wet ponds and two dry ponds to collect, infiltrate, and reuse stormwater from roads and ramps at the new interchange. The stormwater will then be pumped to Applewood Hills Golf Course, where it can be used for irrigation.
“Water is vital to the operations of a golf course,” says Patrick Renner, President of the Wilson Golf Group. “As our climate changes and water becomes more scarce, we want to do as much as we can to protect our local aquifer.” Using stormwater from the nearby interchange will allow the golf course to reduce groundwater pumping by 7 million gallons per year, and will also keep 38 pounds of phosphorus per year from flowing into Long Lake.
According to Kill, the project is highly cost effective and has multiple benefits. Keeping stormwater out of Long Lake will help to prevent excess algae and aquatic plant growth, and the reduction in groundwater pumping may protect groundwater-dependent wetlands and streams in the area, including tributaries to Brown’s Creek.
“There are a lot of wins all around, and we’re happy to be part of the project,” says Ticknor. The new bridge and ramps at Hwy 36 and Manning Ave. will be completed this summer. The stormwater reuse system will be fully operational by 2023.