The Green Building Tools Cities Can Use to Cut Water Pollution

The Green Building Tools Cities Can Use to Cut Water Pollution

I live in California, and about the time each fall when we turn our clocks back to standard time many of us are hunting around our closets or car trunks looking for umbrellas we last saw in April. It's the start of the rainy season out West.

Of course, for much of the nation, rain falls through most of the year. To say the least, we need the rain. But it also comes with increased water pollution. Because of all of the paved and otherwise impervious surfaces in our cities, rain mixes with the pollutants that fall onto our city driveways, sidewalks, parking lots, and streets, creating a witches' brew of polluted runoff.

Across the nation, an estimated 10 trillion gallons a year of untreated stormwater runs off roofs, roads, parking lots, and other paved surfaces, often through our cities' sewage systems, into rivers and waterways that serve as drinking water supplies and flow to our beaches, increasing health risks, degrading ecosystems, and damaging tourist economies.

But it doesn't have to be that way. A major report the NRDC released yesterday, Rooftops to Rivers II, profiles 14 cities of all sizes using "green infrastructure" -- a set of design strategies that mimic nature's own hydrology and allow rain to filter back into the ground right where it falls -- to tackle stormwater pollution and sewage overflows.

The way we built cities before we knew better basically capped the ground in concrete, creating at first currents of runoff that as cities grew became torrents. Green infrastructure is a simple and powerful solution: make cities function from a water perspective more like the natural landscape by making them more pervious and, well, green.

The report significantly updates our first edition of Rooftops, which was published five years ago and became something of a report of record on what was then a growing but still boutique movement to solve the polluted runoff problem plaguing urban areas. I hope Rooftops II helps propel more progress by pulling together all of the newest data on green infrastructure's benefits, attributes, economics -- and lots of information on what cities across the nation are doing to harvest its many benefits.

To help point the way, the report includes a new "Emerald City Scale" that we created to frame and communicate the basic elements of a strong and effective local green infrastructure program. My colleague Jon Devine has blogged about the index and how our case studies cities did in meeting our six-point Emerald City plan. We are also encouraging cities not profiled in this report to fill out an online form, telling us how they are achieving the "Emerald City" criteria. There's a lot of exciting progress out there that we'd like to capture.

The cities profiled in Rooftops to Rivers are using vegetation around parking lots (called "swales"), rain gardens, green roofs, permeable pavement and trees to help absorb the water like sponges. By using green space, swales, cisterns and other techniques, green infrastructure solutions bestow a range of benefits on communities that embrace them.

On top of clean water, these benefits include beautifying neighborhoods, providing more flood protection, augmenting local water supplies, cooling and cleansing the air, reducing illnesses, lowering heating and cooling energy costs, boosting economies, and supporting jobs.

As important as those benefits are, cities are focused on their financial bottom lines. They're using green infrastructure because it delivers results and saves money compared to other ways of reducing water pollution.

For example, a 2007 U.S. EPA study found [PDF] that "in the vast majority of cases…[green infrastructure] practices save money for developers, property owners and communities while protecting and restoring water quality." And just last month, the American Society of Landscape Architects released results of a survey that found green infrastructure reduced or did not influence costs 75 percent of the time.

We're releasing Rooftops to Rivers as the EPA is reforming and updating for the first time in two decades the national Clean Water Act rules that apply to controlling stormwater runoff pollution at the source. This is a huge opportunity (that EPA cannot afford to miss) to catch up to what many local communities are already doing, and ensure that the nation as a whole follows a smart, cost-effective, and multi-beneficial approach to solving leading water pollution problems.

What can EPA do? Well, first, it must move forward and propose a rule, which it has promised to do this year. Second, EPA must make green infrastructure the rule's central focus. That means fashioning the rule update so that new development and redevelopment projects are required to retain stormwater onsite with green infrastructure techniques to keep it from turning into runoff pollution.

This approach should apply throughout urban and urbanizing areas. The EPA should also require retrofits in already developed areas and as part of infrastructure reconstruction projects.

In so doing, the EPA will embody the lessons learned from cities across this country and the leaders who understand that, from an environmental, public health, and economic perspective, green infrastructure is the best approach to cleaning up our waters, while delivering a whole range of additional benefits.

This progress and the prospect that EPA will help it spread is a good reason to smile when raising an umbrella into the season's first rain here in California or wherever it is raining this fall.