A July 19 Baltimore Sun article reported that the Maryland State Highway Administration (SHA) and Baltimore City are testing pervious pavement – which is designed to let water infiltrate into the ground beneath it rather than have it wash off the surface – in a limited set of locations. Pervious pavement could help the State, local governments, and private property owners meet the stormwater runoff treatment requirements that have been mandated by the United States Environmental Protection Agency under the Chesapeake Bay Total Maximum Daily Load and the National Pollutant Discharge Elimination System Municipal Separate Storm Sewer System (MS4) permits.
The use of permeable pavement and pavers has spread gradually in commercial and residential developments, starting in the South, according to Colin Lobo, senior vice president for the National Ready Mixed Concrete Association.
“A lot of universities adopted it, doing permeable parking lots and walkways,” said Kelly Lindow, owner of CityScape Engineering in Baltimore. …
Municipalities in the Chicago area and nationwide also have embraced permeable pavement.
The article noted that pervious pavement still has some challenges – it is more expensive than standard impervious pavement and requires more and different types of maintenance. SHA is testing the use of porous pavement in two locations:
With funds limited, [SHA] is only looking for now at trying it in new projects, like the park-and-ride lot in Waysons Corner and another one off Interstate 83 in Baltimore County, for a combined cost of $1.7 million. Pervious pavement also is being put down on a hiker-biker path near the C&O Canal in Allegany County, a $350,000 item in a larger resurfacing and drainage upgrade project there.
The article also discussed the use of porous pavers by Baltimore City:
In Baltimore, the city is trying porous pavers to see how well they reduce runoff. City officials installed them in the new Upland redevelopment in West Baltimore, and workers are resurfacing an alley grid on East Baltimore’s Butchers Hill with concrete paving blocks, aiming to absorb some rainfall in a compact rowhouse neighborhood that has few other options for corralling it.
Working in partnership with Blue Water Baltimore, a local watershed watchdog group; Biohabitats, a local green engineering firm; and the Center for Watershed Protection, the city has contracted to install pervious pavement in a total of three alleys. They’re also putting in small rain-absorbing gardens to be extended out from sidewalk into the street between parked cars.