HOLDING ITS
OWN
Paving material absorbs water, negates need for
stormwater pond
By DAVE BACKMANN Freeman Staff (Dave Backmann
can be reached at dbackmann@conleynet.com )
FRANKLIN – The surface of the parking lot
poured this week at 7330 W. Rawson Ave. resembles that of a gray Rice Krispies
bar and acts something like a permanent sponge.
And, as strange as it sounds, if the lot made of
a special type of permeable concrete was not poured, Brookfield developer Steve
Nikolas would not have had room to erect two commercial buildings on the site.
Instead, he’d only have room for one.
But
because the 30,000-squarefoot lot and its substructure are designed to hold
stormwater – under ideal circumstances absorbing up to 4 inches of rain per
minute with no ponds forming – Nikolas did not have to build a detention pond to
comply with the Milwaukee Metropolitan Sewerage District rules governing
stormwater runoff.
Minus the detention pond,
Nikolas had space to build a second structure, a 4,000-squarefoot building that
will house a coffee shop and martini bar.
MMSD
Executive Director Kevin Shafer said the Franklin parking lot is an example of a
construction technology he hopes other contractors also will use.
“I think it’s exactly what we hope others will
do,” Shafer said.
“It relates to overflow. The
water has to go somewhere and if it goes into the sanitary system, it could
cause an overflow.”
In place of traditional
concrete, the 4-inch parking lot surface is formed of 3/8-inch pea gravel and a
material called EcoCreto. Water passes through the EcoCreto, then is temporarily
held in 24 inches of underlying stone.
Nikolas
said he has been experimenting with EcoCreto for about five years. Until now, he
and his crew had not found proper equipment to apply the product, mainly the
correct roller screen used in the pouring process.
“I think we’ve perfected this and found the
right property for it,” said Nikolas, president of Zabest Commercial Group Inc.,
16800 W. Greenfield Ave., Brookfield.
Zabest
Commercial Group is a distributor of the EcoCreto product.
Nikolas described the parking lot in Franklin as
the first of its kind in Wisconsin with no stormwater discharge into sewers and
100 percent infiltration of the water into underlying stone and soil.
Along with the Brookfield development company,
Nikolas owns the property being developed on West Rawson Avenue. The second
building covering 6,000 square feet is to house the cancer treatment center
Oncology Alliance Inc.
He said tests indicate
the product is stronger than traditional concrete. “It walks the walk and talks
the talk of concrete, but it is permeable,” he said. “This is ideal for urban
infill situations.”
Chris Leedom, the project
engineer with the Sigma Group, Milwaukee, said pervious concrete parking lots
generally work better in areas with less underlying clay soil and more sand
because water moves more easily through the sand.
The technology is generally more commonly
applied in warmer climates, but has been tried in Scandinavian countries, Canada
and Pennsylvania. Leedom said his company designed a similar, but smaller lot
two years ago for a business in Oak Creek. Submitted
photo A paving crew pours a pervious concrete parking lot at 7330 W.
Rawson Ave. in Franklin this week using a product called EcoCreto. The lot and
its substructure act as a sponge and will hold stormwater before allowing it to
filter into the subsoil. The system, in this case, replaced the need to dig a
detention pond to comply with stormwater runoff rules.