Completing a grant project that began with just an application well over a year ago, the WBL Montessori School unveiled its renovated schoolyard in late August, 2016.

The nature play area includes two large raingardens, which VLAWMO helped fund along with the Ramsey Conservation District (RCD).

So what effect do the raingardens have?

A modeling program called MIDS (Minimal Impact Design Standards), developed through the MN Pollution Control Agency and Barr Engineering provided the insights to what effect the raingardens would have on water quality. Based on soil type, average rainfall, area of turf grass, and area of permeable pavement, the model first predicts what’s in the runoff from the site. Next, the model calculates the reductions based on the area and depth of the raingarden. VLAWMO then keeps track of all these projects within the watershed, tallying up the nutrient reductions for annual reporting to the Minnesota Board of Soil and Water Resources (BWSR).

WBL Montessori raingarden models

With the runoff reductions come other advantages to water quality. As runoff picks up sediment and nutrients, the storm drain system becomes a conduit for whatever’s on the landscape. The end result is the condition of a nearby lake or river, be it healthy or poor in water quality.

The raingardens at the WBL Montessori are modeled to reduce phosphorous by .26 lbs/yr. While this may not seem like much, phosphorous is an especially potent nutrient when it gets into open water. Just one pound of phosphorous produces up to 500 lbs. of algae, which unlike the phosphorous, is highly visible in the water. Algae and the other reductions below help keep water clear, and allows for a healthy aquatic community. For example, certain critters such as dragonfly larvae prefer clear, clean water. As a natural predator to mosquitoes, keeping them around is beneficial to humans as well! Gradually, these raingardens and other green infrastructure projects set up a system that will continue to protect water for future generations.  

See our montage of the project in the video below. For more information on VLAWMO’s landscape grant program, visit our webpage here.