Water Quality Connections

by Kate Morgan, Water Policy Director

Throughout the audit and interview phase our project , Strategic Plan for Code and Ordinance Revisions to Advance Green Infrastructure in the MN Watershed, Juli Beth Hinds, our project consultant, and I heard a common refrain from our municipal partners concerning pervious pavement, “Pervious pavement? It doesn’t work here. It fails. It’s too big a risk. It can’t hold up to our winters.”

surfaceWe’re working to change these perceptions in order to accommodate the goals of Milwaukee Metropolitan District’s (MMSD) ambitious Regional Green Infrastructure Plan. The goal of this plan is to capture by 2035 the first ½ inch of rainfall where it falls across MMSD’s entire service area. When calculated over the MMSD’s service area of 411 square miles, we’re talking about a sizable volume – 740 million gallons of water.

To reach this goal, a whole range of green infrastructure practices will need to be employed and implemented region-wide. Pervious or porous pavement is slated to be major strategy with the plan calling for pervious pavement to capture 21% of the 740 million gallons. This is equivalent to 1190 acres of pervious pavement for streets and parking lots.

With permeable pavement and related materials, rainwater infiltrates through the permeable materials to a prepared substrata that also infiltrates the rainwater or captures the infiltrated rainfall releasing it slowing into the surrounding substrate soils.

In response to the perceptions that surfaced through the audit, our project partner, Stevan Keith, Sustainability & Environmental Engineer for Milwaukee County’s Environmental Services Unit, is developing a porous materials clinic to be held this summer. Keith and his department will bring together a group of experts to outline best management practices for the installation of porous materials as well as to highlight local success stories.

And we’ll tackle the problem from the codes and ordinance side of the equation, identifying those codes and ordinances that inhibit the use of porous materials. Through projects like ours, bringing together a diverse group of partners who share a common goal, we can help make the capture of 740 million gallons of rainwater a reality.