WAUWATOSA — Changing the longtime engineering mind-set of deliberately channeling rainwater off of property in the Milwaukee area could save tens of thousands of dollars, attendees of a clean water conference were told Wednesday in Wauwatosa.
Milwaukee landscaping contractor Bryan Simon was pelted with questions as he showed slides of his own small-business property, which has been transformed into a prototype of storm water conservation disguised as attractive brick, cobblestones and flowers, at the Clean Rivers, Clean Lake Conference sponsored by the Southeastern Wisconsin Watersheds Trust Inc., or Sweet Water.
Where did he get the roof garden plants? What kind of fabric lining was used in the underground water storage system? Can the water-permeable parking lot withstand heavy truck traffic? Can you have one if your building has a basement? And how long will it take for the investment to pay off?
“You can recoup your costs in 10 years. Come on down and take a tour,” enthused Simon, who remodeled his one-acre property on S. 6th St. in Milwaukee to include a porous parking lot and a garden that self-waters by continuously pumping rainwater collected and stored underground. Runoff water from one steep slope of his A-frame building feeds the rain garden system. Runoff from the other slope is collected in a rain barrel that Simon hopes to connect to planters.
A flat roof covering the rear of the building is now green with sedum plants. What appears to be a long, slightly mounded row of cobblestones along the property line is actually a swale designed to absorb any last traces of rain water or melting snow.
That’s water that won’t be flowing into Milwaukee’s already overburdened storm water system. And it’s saving Simon $1,380 each year in storm water fees charged by the Milwaukee Metropolitan Sewerage District.
In 2006, MMSD began charging property owners $8 every three months for each equivalent residential unit (ERU) of non-porous surface, including roofs, driveways, parking lots and sidewalks. By 2010, the fee had risen to $14 per ERU per quarter.
While homeowners are typically charged for only one ERU, commercial properties are charged 1 ERU per 1,610 square feet of impervious surface. It’s not unusual for business properties to pay $20,000 or $30,000 a year in storm water fees, said Timothy Thur, storm water manager for the city of Milwaukee.
But businesses can qualify for significant fee reductions by following best-management practices, Thur said, such as those installed at Simon Landscaping.
Simon’s property was being charged for 24 ERUs; now, it’s rated at five ERUs, reducing MMSD fees from $400 to $55 every 3 months. In addition, Simon says he anticipates 35 percent to 50 percent lower heating bills due to the green roof, and says he no longer needs to spend money salting his parking lot in winter.
“There’s no build-up of ice,” he said. “As soon as the sun comes out, it melts and when it melts, it doesn’t ‘pond.’ It’s absorbed into the pavement.”
That “pavement” is actually 3-inch deep bricks, deliberately spaced apart. A porous layer of black granite chips fills in the gaps between the bricks, absorbing runoff. Simon redid his entire parking lot this way, but says businesses with very large parking lots only have to retrofit a portion with permeable surfacing to gain the benefits. He doesn’t, however, recommend a porous parking lot adjacent to a basement unless the grading will slope away from the building.
Overall, Simon estimates he spent a little over $100,000 on the improvements, excluding the green roof, which was funded by MMSD through the 2010 Regional Green Roof Initiative Grant Program.
Karen Sands, MMSD manager of sustainability, said the $5 million, one-year program has about $1.5 million in left-over funds that are likely to be made available to other businesses in 2011.
Thur urged more businesses to consider storm water best management practices to help sewerage districts cope with increasing urbanization and the resulting increase in water runoff, chemical runoff and adherence to tougher environmental ordinances. But he also stressed the individual payoff.
There’s a perception that porous surface parking lots and green roofs are more expensive to install and maintain, compared to traditional surfaces and roofs, he said. “However, as more and more storm water … projects are implemented, there’s a realization that such projects can really provide a financial benefit in addition to the water quality and quantity benefits,” he said.
Tim Bate, manager of planning, research and sustainability for MMSD, acknowledged that the concept of taking widespread measures to absorb rainwater is new.
“It is a paradigm shift from what we engineers learned from our early days,” he said. “The sort of design concept was to shed water from the property. Municipalities, I think their M.O. in the past has been, ‘Get that water out of my system, let the sewerage district deal with it,’ (but) we’re all in this whole water quality, water restoration theme together and we need to help each other out.”
“There’s a place for all of you to encourage your public officials to make this happen,” he said.
— By Kay Nolan