Welcome to the Heritage Park Stormwater Walking Tour
This stormwater treatment system integrates stormwater management into the urban fabric and “harvests” water to create public amenities.
Background
Heritage Park transforms an urban landscape into a diverse and sustainable natural community. Restored wetlands and prairies wind through the neighborhood cleaning water runoff and providing habitat for wildlife while adding beauty with seasonal blooms and textures.
Wildlife at Heritage Park. Credit: MWMO
Prior to redevelopment, stormwater in this area flowed straight to the Mississippi through underground pipes, so that sediment, road salts, phosphorus and other pollutants flowed directly into the river as well. The Heritage Park stormwater treatment system, with its filtration devices and basins, is designed to remove 70% of suspended solids (the main target of this stormwater project) as well as reduce total phosphorus and metals. The result is cleaner water downstream and thus better habitat for fish and other wildlife.
During construction vs after completion of Heritage Park. Credit: MWMO. Slide to see progression of time.
The treatment system has been designed to effectively cleanse stormwater to protect downstream water quality, while providing attractive green infrastructure. What you don’t see is that there are a number of underground treatment devices that clean water as you follow along the path. Each step of the treatment process incrementally cleanses the water further. You'll notice as you walk, you are following a series of cascading stormwater devices.
How it Works
When rain falls or snow melts in a city, the water often lands on nonabsorbent surfaces like sidewalks, streets, and rooftops. Water runs off these surfaces collecting pollutants such as oil, dog waste, grass, and sediment on its way to our lakes and rivers. Here at Heritage Park, wetlands and native plants help to filter and cleanse the runoff making the Mississippi River cleaner and healthier for plants, animals, and people.
Cleaning Components
Several stormwater treatment devices, or cleaning components, make up the Heritage Park system. Each play an important role in further cleaning the water as it makes its way from street runoff to the Mississippi River.
Follow the arrows to see how stormwater flows through the filtration system. Scroll down below to see what this looks like in real life at Heritage Park.
Flow of water through stormwater devices. Stormwater from streets and sidewalks enters a storm drain. A pipe routes the water into a grit chamber where trash and heavy sediment are separated from the water. The trench forebays collect smaller debris and sediment and the level spreaders slow runoff. In the filtration basin, native plants filter the water and remove pollutants, and the filtered water overflows a weir into the pond. The pond further filters and cleans the water before it makes its way to the Mississippi River.
How The Plants Help
The plants growing in Heritage Park are busy. Stalks and stems help the soil absorb water; with the water, the plants absorb pollutants and convert many of them into less harmful materials. Plant root systems stabilize the ground, prevent erosion, and keep the soil loose enough to allow water to travel through the ground. Root systems, along with leaves and other vegetation, trap excess sediment before it reaches a body of water.
The Walk
At Heritage Park, there are two different walking loops (The North Loop and The South Loop).
The North Loop is the larger of the two loops (approximately 1 mile). Follow along below for a tour of the North Loop.
Stop #1 (Start)
Stormwater from streets and sidewalks enters a catch basin. A pipe routes the water into a grit chamber where trash and heavy sediment are separated from the water.
Stop #2
The Heritage Park stormwater treatment system employs more than 40 species of native plants (like New England Aster, Hummock sedge, and Black-eyed Susan) to help filter sediment and other pollutants that are washed off of roads, sidewalks, rooftops and yards when it rains.
Stop #3
Benefits of native plants:
Plants in their native habitat require less water and no pesticides or fertilizers to keep them healthy which reduces water usage and improves water quality
Installing and maintaining a garden lush with native plants costs less than installing and maintaining a grass with a few shrubs
Native plants produce pollen, fruit, and seeds that attract songbirds, dragonflies, and butterflies
Stop #4
After moving through the grit chamber, the trench forebay and level spreader filter smaller debris from the water. Water flows out of the trench forebay into a vegetated filtration basin where native plants and special soils filter the water.
Stop #5
After moving through the filtration basin, remaining sediment falls to the bottom of the pond, further filtering and cleaning the water.
Stop #6
You're currently standing on top of a weir which connects the filtration basins to each other. At the end of this filtration basin, an outlet structure connects to the next filtration basin under the road.
Stop #7
Limestone rocks act as a "dry rock channel" and mimic the historic path of Bassett Creek, which used to flow through here.
Once you reach the end of this section, before crossing Olson Memorial Highway, turn around.
Stop #8
As mentioned earlier, the large pond that you are crossing has clean water because of all of the stormwater management devices prior.
Stop #9 (Finish)
If you look across the pond towards N 8th Ave. you can see an opening that says "To the Mississippi". It is here where all of the hard work that the stormwater devices have done pays off, as the filtered water makes its way to the Mississippi River.
The South Loop is the shorter of the two loops (approximately 1/2 mile). Follow this path for a loop around the pond with benches along the way to relax.
Aerial Photograph (facing east) of Heritage Park's Southern Loop.
Stop #1 (Start)
This small pond is meant to remove additional sediment from the large area draining to the park before it enters the filtration basin. As you walk you'll see that the filtration basin creates habitat for native plants and pollinators.
Stop #2
Remember: the pond is more than just a pretty feature. It is here to treat the dirty stormwater before it goes to the Mississippi. As water flows in, it takes out oils, pollutants, sediment, and other debris that might otherwise pollute the river where the water is headed next.
Stop #3 (Finish)
The large pond serves as an amenity for the community with clean water due to the hard work and treatment from stormwater devices upstream.
For more information, check out Mississippi Watershed Management Organization's Heritage Park Project Fact Sheet
Thank you for taking the Heritage Park Stormwater Walking Tour! We hope you enjoyed your walk and learned a little something along the way.
