Type: Mini Grant, Planning Grant, Action Grant
MWMO Funding: $3,000 Mini, $6,800 Planning, $50,000 Action
Over the course of several years, FamilyWise Services undertook the development of a comprehensive landscape master plan for their property with funding from the Toro Foundation. Goals included improving green spaces, fixing parking lot degradation, and revamping the on-site playground. FamilyWise also wanted to redirect water that was draining to the front door and causing dangerous ice patches during the colder months. The MWMO has awarded three separate Stewardship Fund Grants to help plan and fund the improvements at the site.
Starting with a Mini Grant in 2015, FamilyWise removed impervious areas, including sidewalk and stairs, to make way for a raingarden at the northeast corner of the property. The raingarden infiltrates stormwater that runs off of the adjacent 3,200-square-foot parking lot, and which used to flow untreated into the stormsewer on University Avenue. By capturing this runoff, the raingarden improves local water quality, eliminates nuisance puddles at the building’s main entrance, and reduces stress on the city’s stormwater infrastructure. Daugherty Business Solutions volunteered to assist with the initial planting and fall/spring maintenance. Volunteers from Church of the Open Door have also assisted with maintenance.
In 2017, an MWMO Planning Grant was utilized to design additional stormwater improvements for the entire property. The project site is well-suited for infiltration, with sandy loam soils and an infiltration rate in some areas of greater than 6 inches per hour. An MWMO Action Grant and $50,000 Hennepin County grant funded the redirection of the stormwater flowing from the roof drains and western parking lot to a tire-derived aggregated (TDA) infiltration system installed in July 2020. TDA has been used for years within the road construction industry, but has seen limited use in stormwater applications.
The TDA system was designed to maximize cleaning, temporary storage, and infiltration of water into the underlying soil to prevent it from going to the Mississippi River untreated. A stormwater pretreatment sump, consisting of interlocking bricks atop sandy soils, is located at the corner of the site along University Avenue SE. This area filters out sediment before the water goes through a catch basin in a lower tier separated by a weir. There are also two catch basins positioned beneath the roof drains. The water from each catch basin is directed to a primary TDA distribution pipe beneath a manhole in the center of the parking lot. Immediately beneath the pavement, there is 300 cubic yards of aggregate base and granular borrow, which is made up of crushed concrete, bituminous material, brick, and limestone. Much of this material was sourced directly from FamilyWise’s old parking lot, which had experienced settling issues over time due to an old house foundation beneath the surface. Bolander, an earthwork/crusher company located less than 2 miles from FamilyWise, custom-processed the materials for the project. A non-woven geotextile fabric separates these top layers from 320 cubic yards of TDA. The tires were regionally sourced from Tire Aggregate LLC and custom-shredded into a “C” shape to maximize water holding capacity. TDA has large voids available for holding storm water (averaging 50–60 percent water-holding capacity), allowing maximum storage and infiltration for the space available.
It is expected that TDA, along with the rest of FamilyWise’s drainage catchment plan, will handle a 100-year rain event for the entire property once all pieces of the plan are installed and connected. The system is fully disconnected from city stormsewers, with only an emergency overflow to the street. The end goal is for the TDA system to not only manage water from their roof and west parking lot but also accommodate overflow from their frontage raingardens, which they hope to install as the final stage of their plan. Beyond the stormwater storage benefits of TDA and its lower price compared to conventional aggregate storage systems, the project demonstrates a beneficial use for old tires and keeps them out of landfills or incinerators. Since the tire pieces are underground, they are also no longer exposed to oxidation or UV degradation from the sun. Studies have shown that levels of metals or other various organic compounds found in TDA leachate have been below applicable water quality thresholds. Research also indicates that TDA reduces levels of phosphorus and certain other pollutants, creating a water quality benefit.
Through all three Stewardship Fund Grants, the project has included educational benefits for daycare staff, children, families and volunteers through interpretive signage, newsletter articles, social media postings and raingarden maintenance.