Dan Rodricks: Too much pavement, not enough trees, as shopping habits change

All over the Baltimore region and central Maryland, you see them — vast parking lots built in the heyday of retail shopping and American consumerism now under-utilized in the heyday of e-commerce and American consumerism.

I draw a direct line between giant parking lots — acres of hard, impervious surfaces — and flooding, stormwater and the ugly, polluted water that pours into the Chesapeake Bay. 

Monster rainstorms, like those in Texas and New Jersey this month, flood rivers and creeks, streets and entire towns. They are so overwhelming that parking lots — parking lots? — might seem like a minor contributing factor in the destructive consequences of a deluge.

But vast parking lots, built to meet state and local requirements for maximum shopper visitation — on, say, the Saturday before Christmas — generate peak runoff in urban areas. They also generate a lot of heat. Mix heavy rain and heated asphalt and that’s a lot of hot, dirty water flowing into the tributaries of the Chesapeake. 

There are so many impervious surfaces in the Baltimore region and central Maryland — not just sprawling parking lots, but roofs on massive warehouses, stores and office buildings — that some remediation was needed. So, in 2012, Maryland legislators enacted the Watershed Protection and Restoration Act, though you probably know it as the “rain tax.” 

When he ran for office in 2014, former Gov. Larry Hogan mocked as a “rain tax” the state’s effort to impose stormwater management fees to slow runoff pollution. Hogan ridiculed the idea, and in time legislators kicked some of the teeth out of the law. The Hogan attack on the “rain tax” helped him win office — political analysts called it brilliant — but it denigrated a science-based attempt to improve water quality in the bay and lessen the impact of flooding. Denigrating science, opposing a fee or tax to raise funds for environmental improvement — that’s a classic Republican thing, now writ large in the Trump era.

Despite the retreat from the original intent of the law, Baltimore and nine counties all file plans for their stormwater remediation efforts — and how they will finance them — with the Maryland Department of Environment. In its latest report, MDE found that the state’s 10 largest jurisdictions were meeting their multi-year goals for restoring impervious surfaces into areas where stormwater can naturally soak into the ground. The practices include wet ponds, swales, rain gardens, green roofs, permeable pavement, rainwater harvesting and submerged gravel wetlands. Baltimore and the counties are at various levels of meeting their long-term goals. In all, says MDE, nearly 43,000 acres of impervious surfaces have been restored so far, representing about 25% of the baseline goal.

All good, but it still seems that the private owners of massive parking lots have not adjusted to the reality of changing consumer habits. The closing of brick-and-mortar stores is reportedly at a record pace this year; Coresight Research, a retail data firm, predicts that 15,000 retail stores will close, double the closures of 2024. That’s not something to celebrate; it’s just an acknowledgement of reality. It means less need for parking spaces, and that is something to celebrate.

The owners of these large commercial properties seem to be slow to recognize the opportunity being presented.

Plant trees! Give up some of that wasted space for rain gardens.

Shopping center parking lots are way too big for their present use in the e-commerce age; many of them could be returned to natural conditions. They would look more appealing, and, depending on the location of the parking lot, their owners would likely in the long term see a lower tax burden. 

More of the roofs of massive buildings could be used to capture rainwater, significantly reducing runoff and the risk of flooding.

There’s a similar problem in rural-suburban settings — runoff from roads, driveways, parking lots, sprawling lawns and the roofs of large buildings on top of the long-standing issue of runoff from farm lands. 

Last week, I stopped by the Big Gunpowder Falls as the river passes under the Corbett Road bridge in Monkton. The water originates cold and clear at the Prettyboy Dam in northern Baltimore County, a major source of drinking water for the Baltimore region and good enough for classification as a blue-ribbon trout stream. But, following a heavy rain, it turns big-muddy after passing through agricultural and suburban areas where small runs and branches feed into the Gunpowder mainstem. Not enough rainwater gets absorbed into the ground.

The answer for this: Landowners, including farmers, need to plant more trees or, if possible, create more wetlands where rain can be more gently absorbed into the ground. There is plenty of information available from the state and local jurisdictions on how to do this. It means giving up something — maybe a few acres from a soybean field, or a portion of a large lawn — for a greater, greener environmental benefit. 

Dan Rodricks’ column appears weekly in Fishbowl. He can be reached at djrodricks@gmail.com or via danrodricks.com.