In less than a week (June 11 to be exact), the Environmental Protection Agency (EPA) is expected to issue updated rules (in draft form) for stormwater management. While they have signaled some really good ideas (namely custom rules for redevelopment and urban areas), the Agency may have to punt given other unresolved issues on mandatory retrofits and expanding regulatory scope.
Nonetheless, any notice is a chance to crank on PR, so now is a good time to take a critical look at how the first generation of water rules is panning out. If you want more background on why the existing rules are swipe-worthy, I wrote something for Planetizen called “A Browner Shade of Green” in 2007. The article essentially noted that what looks good on paper might not be what is best for the environment. While that article was focused on sprawl, this blog post is more about stormwater management and infill. This is not an anti-infill story. Rather, the bottom line is how convenience and obsession with rules for individual lots are driving a lot of crappy water outcomes.
Here is a typical infill houses in Arlington.
At first blush, one might marvel at how smart these buildings are from a checklist point of view. First the house has no gutters, which means water is not shunted directly to the street and storm sewers. The “effective impervious surface (EIA),” or the amount of concrete connected to curb and gutter is low. You have two driveway strips and a small walkway. The EIA is about 5% (sound of fist bumping in the background). All the other water gets filtered through the landscaping and rocks. There is a “granny flat” unit in the back and this house is within walk distance of the Clarendon metro and several bus lines.
But let’s scope out a little bit because there is more to this story. In the picture below, the main thing to pay attention to are the two little pipes that spit out to the curb. These are connected to sump pumps, which are needed to support living space in the basement. Let's follow how raindrops travel on the house to the left: the water hits the roof, runs off into the rocky foundation treatment, seeps in and gets pumped out to the street. It’s hard to tell what proportion of rainfall makes its way back out to the street, but when it rains my neighborhood sounds like the fountain show at the Bellagio – sideways. While runoff in general, and dog poop and urban detritus specifically, are listed as the Bay’s worst enemy, perhaps finished basements ought to be higher on the list.
So what about convenience and rules?
- The Clean Water Act’s first Act was marvelous – the industrial rules turned around flaming, green rivers. The next increment, Total Maximum Daily Loads (TMDLs) were less than stunning, since farmers, cities and industry spent more time denying culpability than cleaning up. The third act turned out to be more powerful than expected since the stormwater rules, for the first time, inserted themselves into local zoning codes.
- As it turns out, codes are a fabulously easy way to write and enforce rules, but not always the best way to clean up water. Codes work for individual properties, but as the photos above show, the sum can be less than the parts. I am guessing the construction permit/sump pump guy and stormwater guy have no idea of how each others’ professional fates are entwined.
- Finally, environmental groups are pushing for the strictest codes as possible as a “win.” It is viewed as an efficient path to massive scale. But this is not how cities work. Attention to individual projects is how sprawl works.
Infill poses several big dilemmas that can really be summed up in a short phrase: the water has to go somewhere.” This is much larger than a blog post can digest and there may be a lot more to talk about a week from now. But there are a couple of things people need to think about because the tension between the large scale benefits of density and the localized impacts of imperviousness are real:
Individual Lots – what happens on individual sites still matters, but we have to go beyond what looks good on paper. In 2006, Melcy Curth Pond and Greg Kacvinsky of Clark Dietz in Illinois presented a paper (available via WaterBucket) on tear downs. While this paper includes a look at imperious surface coverage, it notes several other “aha” factors:
- Common changes in topography alter existing drainage paths. The old bumpy yard gets smoothed over, giving runoff a faster, direct route to neighbors’ yards or the street.
- In addition, once-flat lots are converted into trapezoidal pyramids for better basements, which also facilitates faster flows from the property (the paper references above includes a great graphic of before-after).
- Deeper basements constructed on gravel will provide groundwater quick access to the stormwater conveyance system through sump pump connections. This is a big deal because you may find a sump pump not only evacuating infiltrated water from one lot, but others as well.
The new rules will only be successful if we look at real data, what's going on and adapt.
Planning Areas – If cities are not the mere sum of individual lots, what are they? They are symphonies, with lots of flows like people, water, traffic and money. The most powerful thing the next rules can do is elevate the role of shared stormwater management that looks at these flows. This can be via planning, in lieu of fees, impact fees, redevelopment incentives or Tax Increment Finance districts. This middle scale of planning is so ignored, but so important for the intersection of the environment and economic development. It is also important for the protection of property and climate adaptation. More to come next week.