Lakeaires Elementary Raingarden

Quick Facts:

Basin size: 952 ft

Basin depth: 2.5 ft

Year built: 2014

Infrastructure strategies: Drain tile, dry creek, filtration basin, underdrain

Funding:

White Bear Lake School District 624 staff sought and secured VLAWMO grant funding through the Community Blue grant program. The Community Blue grant consisted of $19,000 and the school district provided a $6,000 match in addition to in-kind services. VLAWMO utilized Minnesota Clean Water Funds to support the Community Blue program at this time.

The scope and purpose of the Community Blue program has since shifted to smaller educational efforts and demonstrations.

Reason for project:

The Lakeaires Elementary parking lot was experiencing a severe erosion issue at the Southwest corner. Parking lot runoff topped over the sidewalk, over a nearby turf area, and back into the street. Over time, this created a gully that increased its severity with each rainfall, sending excess sediment and nutrients into the stormdrain system. Stormdrains in this area drain into East Goose Lake.

When erosion and drainage issues occur, fixes may also include opportunities for a more comprehensive effort that benefits both the immediate site and the surrounding watershed. A partnership between VLAWMO and the White Bear Lake School District 624 made this possible through planning and harnessing resources.

Construction:

A comprehensive fix was planned by landscape designers to include a drain tile beneath the sidewalk, regrading of the turf area, a dry creek consisting of trap rock, and a raingarden filtration basin.

To limit ponding in this basin, an underdrain outlet pipe was installed. With this, the basin acts more as a filter for treating stormwater as it passes through to the stormdrain network. While some raingardens focus more on infiltration into groundwater, the Lakeaires raingarden is an example of raingardens built in difficult clay soils. In these situations, a mixture of native soil, sand, peat, and compost are brought into the basin to provide a valuable treatment effort that still helps improve the impact of stormwater on local waterbodies.

In the field of green infrastructure, the concepts at play are known as bioretention and biofiltration. Stormwater is retained by a biological system of plants, roots, soil, microbes, and healthy soil bacteria. Together they slow down stormwater and filter the nutrients and sediment it carries.

Native plants included in raingarden: Alma Potschke Aster, Fringed Brome Grass, Yellow Dogwood, Fox Sedge, White Turtle-head, Joe Pye Weed, Blazing Star, Great Lobelia, Mountain Mint, Prairie Cordgrass, Blue Vervain