Hisdahl’s Trophy has been in business in White Bear Lake since 1967. Keith Hidsahl first purchased the business from his parents in 1995, and moved to his current location in 2005. In 2019, he started a major remodeling effort that included a new building and parking lot. In the process Keith stumbled across some stormwater challenges, but also saw them as an opportunity to try something new. With some creative planning and networking, the final result was something that enhances both the store experience and the surrounding watershed.
Project size: 14,375 ft2
Drainage area into project: 1,220 ft2
Volume of water generated in project drainage area in a 1” rain event: 6,451 gallons / ~161 bathtubs
Basin depth and overflow design: 1” depth, overflow routed to pop-up device that drains into turf area and into street
Annual stormwater volume collected: 12,056 gallons
Total phosphorus (TP) treated by raingarden: .03 lbs/yr (1 lb phosphorus creates 500 lbs algae)
Total suspended solids (TSS) treated by raingarden: 5.4 lbs/yr
Receiving waterbody: Lambert Creek/ East Vadnais Lake
Native plants: Giant hyssop, blue flag iris, columbine, rose milkweed, black-eyed Susan, lake sedge, Pennsylvania sedge, purple coneflower, big bluestem, joe pye weed, prairie cordgrass, switchgrass dotted blazing star, red osier dogwood, black chokeberry
Runoff estimates provided by MPCA Minimal Impact Design Standards (MIDS)
What runoff issues were you facing at your store?
The roof runoff was landing right into the front entrance and into the parking lot, which made for a disaster zone for ice and winter maintenance. There was also an erosion issue and sedimentation happening on the side of the building along highway 96, with runoff washing from the roof, down the slope, and into the street, but taking the slope with it. All the issues were corrected by a new planting along 96 and an underground connection from the downspout into the raingarden. Routing the water under the sidewalk and parking lot spares the use of salt and ice chipping. The raingarden’s overflow directs water slowly into the grass, which is working great.
What motivated you to go the route of making a raingarden?
I needed to do something with the shop to solve the issues. To do the development the way it was planned, the city had a stormwater retention requirement for a certain amount of impervious surface, so this was a strategy to meet that need.
It turned out exactly the way it should be, and I like it. I’ve always been interested in how water flows, where it goes, and how it runs off, it’s just fun to watch. It’s satisfying when it works the way its supposed to work.
What strategies or needs went into the design process?
The raingarden has an underground gutter inlet that takes water from the roof, under the sidewalk and parking lot, and into the raingarden. The raingarden overflow is designed to let water out when it reaches a certain depth, and it drains slowly into the grass from there. I haven’t noticed any overflow reaching the sidewalk at the bottom of the slope, so the raingarden must capture most of it and the grass can take care of the rest. The raingarden inlet, outlet, and the front planting along highway 96 has splash rocks to slow down the high intensity runoff spots. Tyler from VLAWMO helped with the design and sizing, while Connie at the City recommended the gutter inlet strategy to take water from the downspout under the sidewalk.
What’s the maintenance been like so far? Are there any challenges or learning curves?
There’s learning curves for sure, but no challenges. The biggest thing for us is not spraying the grass clippings into the raingarden. I haven’t minded some basic weeding, which I kind of like. I used to help with the White Bear Lake historical Filibrown house just down the street, and took some horticulture classes in high school, so I like taking care of things like that. It’s been easy to check it out in the morning, pull some weeds, and do a bit of watering to start out the day. It’s like taking care of your little baby [laughs].
What has surprised you as you’ve maintained the project and watched it grow?
How well it’s doing! It’s cool to see how well it functions, and how it actually drains. I thought it’d be a big muddy mess with water flooding and woodchips drifting down the hill, but that’s not the case. I like color a lot and was wary of having too much green. But it does have some great color popping out. Color even changes through the season as other flowers bloom.
What would you say to businesses who might be interested in trying out a raingarden?
I initially wasn’t really interested in doing anything innovative, to keep costs down. I wanted the value in the building more than the land around it, but the VLAWMO cost-share grant really helped. It all worked out and the universe happened, so I’d say go for it!
It’s really the same amount of maintenance as before, but you have less space to mow and use machinery on. This year I only mowed my personal lawn at home twice, which is great for me since I don’t really like lawns. When it comes to monument signs, plan ahead for how much space a sign will take and how much space the raingarden needs.