Connecting McMansions to water runoff problems

Echoing a post from a few days ago, a editor to the letter suggests the construction of McMansions has led to more flooding problems in Needham, Massachusetts:

The recent Times article on flooding after our “hundred year storm” didn’t mention one likely contributor to the storm water runoff problem — McMansions. Teardowns surely contributed to the recent flooding, because each new McMansion’s large footprint eliminated a big chunk of drainage land from Needham’s overall water absorption capacity. And building large homes on previously open lots is an even more direct “drain” on our Town’s total runoff capacity.

I’m sure someone could go through the records and calculate exactly how many acres have been lost to big houses (and driveways) over the past 10 years of heightened development. Though we haven’t exactly “paved Paradise and put up a parking lot,” I’m guessing this is enough of a factor that it should be taken into account as Needham considers its longer range development future.

At face value, this seems to make sense. However, I would still have a few questions:

1. What if the new teardown McMansions actually include more efficient drainage systems? This might occur because of updated building codes. I’m not quite sure how this might balance out against having a larger footprint.

2. Is the problem really McMansions, large houses on smaller lots, or is this more of a problem of sprawl in general? Perhaps bigger suburban houses are worse than smaller suburban houses when it comes to water issues but it seems like the underlying problem might be suburban development in the first place.

3. Are there better ways for homebuilders to limit water runoff with new homes? If so, why not require these options for new homes? Local municipalities could make such decisions if they are unwilling to limit more sprawl. Why not require permeable driveways and roadways in new developments?

Chicago tries to solve stormwater issues with Deep Tunnel but is behind in utilizing greener options

The Chicago Tribune suggests while Chicago has pursued the impressive Deep Tunnel project to relieve stormwater issues, the city has fallen behind in pursuing greener alternatives:

Cities from Philadelphia to Seattle already are moving aggressively to prevent basement backups and sewage overflows without the expensive work of laying pipes and boring tunnels. Milwaukee is the first city in the nation with a federal stormwater permit that legally requires “green infrastructure,” such as streets and parking lots with permeable pavement and neighborhood rain gardens designed to capture the first flush of stormwater…

For instance, the Green Alley program promoted by former Mayor Richard Daley has overhauled just 1 percent of the 1,900 miles of Chicago alleys with permeable pavement, according to city records. Other than a showcase project on Cermak Road in the Pilsen neighborhood, city officials could not provide details about any other street outfitted with green infrastructure…

Daley’s 2003 “Water Agenda” and 2008 “Climate Action Plan” promoted green infrastructure as a solution. Mayor Rahm Emanuel embraced the idea last year in his “Sustainable Chicago 2015” plan, which called for making the projects a routine part of the city’s bricks-and-mortar budget and promised to annually convert 1.5 million square feet of impervious surfaces into areas that allow runoff to seep into the ground.

But despite the years of talk about green alternatives, the city’s money and political focus largely is still on big-ticket construction projects like Emanuel’s program to replace and refurbish old sewer lines, funded in part by doubling water bills for the average household by 2015.

The larger official response to flooding and sewage overflows in Chicago and suburban Cook County is the Deep Tunnel, a network of massive storm sewers and cavernous flood-control reservoirs that has been under construction since the mid-1970s. The Metropolitan Water Reclamation District, a tax-supported agency that operates independently from city government, has spent more than $3 billion on the project but isn’t scheduled to complete it until at least 2029.

There seem to be several issues at work:

1. Deep Tunnel is a sunk cost already and it will still be years before it is fully operational. Can a government back away from such a large project, supposedly one of the largest civil engineering efforts in the world, when so much money has already been spent? This kind of retreat with billions spent already is difficult to envision. Also, I assume we know more about stormwater management today than people did in the 1960s and 1970s when Deep Tunnel was planned.

2. The greener alternatives seem to take a different approach to stormwater. Instead of relying on a large, centralized system, it sounds like other cities have stricter requirements for individual property owners. These owners can’t foist the problem off on the city or nearby properties; they have to find ways to reduce their contributions to the system.

3. Chicago has tried to promote a greener image over the last decade or so. Mayor Daley was fond of pointing out the city’s green roof initiative. Here is a little bit more on Chicago’s green roofs:

“If every rooftop in Chicago was covered with a green roof, the city could save $100 million in energy every year,” said Jason Westrope, a developer for Development Management Associates, who has overseen the building of green roofs in the city.

Green roofs also help absorb stormwater runoff. That’s important because the city’s stormwater drains through its sewers, and if the system gets overloaded after a big storm, that wastewater is in danger of backflowing into the river, the lake, and even into people’s basements.

Chicago already has 359 green roofs covering almost 5.5 million square feet — that’s more than any other city in North America. But city planners are pushing for even more.

Chicago has mandated that all new buildings that require any public funds must be “LEED” Certified — designed with energy efficiency in mind — and that usually includes a green roof. Any project with a green roof in its plan gets a faster permitting process. That combined with energy savings is the kind of green that incentivizes developers.

Does this assessment of Deep Tunnel work against this green image? Compared to other major cities, how exactly does Chicago rank in terms of green programs and initiatives? It is one thing to look at a single project, even a massive one, compared to an overall assessment.