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Water | Ecotrope

A guide to the "Emerald City" sewer system

Somewhere over the rainbow ... a world where rain doesn't lead to sewer overflows or a deluge of polluting stormwater runoff.

Somewhere over the rainbow … a world where rain doesn't lead to sewer overflows or a deluge of polluting stormwater runoff.

Earlier this week, I reported on a study by the Natural Resources Defense Council on how Portland, Seattle and other cities are directing rain water into living plants – on rooftops, along roadways, and in backyards – instead of sewer pipes.

There are many reasons why cities would want to do such a thing: Court orders to reduce sewer overflows, water pollution regulations, reducing the cost of new pipes and water treatment facilities, controlling floods, recharging groundwater reservoirs, mitigating the “heat island” effect of concrete-laden cities … the list goes on.

But a new one may be just around the bend.

The Environmental Protection Agency is looking at new rules for how cities manage storm water. So, at some point, adding “green infrastructure” to contain rainwater could be required.

The NRDC study released this week measured 14 cities’ progress toward greener sewers on an “Emerald City” scale. To get to greener stormwater management, the study suggests, you could wait and follow the EPA’s yellow-brick road … or look at what Portland and Seattle are doing to stop rain where it falls – before it runs away and pollutes nearby watersheds. So, let’s take a peek at their roadmaps.

Neighbors Fight Stormwater Pollution by Building Rain Gardens from EarthFix on Vimeo.

I talked with both cities, the EPA and NRDC and came up with these 10 ways Portland and Seattle are leading the way to greener stormwater systems (and for some added visuals, see EarthFix reporter Katie Campbell’s video above):

1. Making new rules for new developments:

This year, the Oregon Department of Environmental Quality mandated that development projects capture and treat 80 percent of the average annual stormwater runoff on site. The cheapest way to do that? Probably planting vegetation.
Tracy Tackett of Seattle Public Utilities said the city’s Green Factor program increased green space requirements for new developments without a major outcry from developers.
“That one had very little resistance because it went from this square footage of landscaping to this much green space,” she said.

2. Adding onto existing city plans for new infrastructure:

Tackett said Seattle is using green infrastructure as a way to solve problems while serving multiple purposes. Areas that are already in line for new bike trails or sidewalks, for example, can also get a greenway upgrade:

“All our natural drainages were places where we needed infrastructure like sidewalks, so we got a net positive impact on the creek while also improving the city landscape,” she said. “It’s a way to get more value from the money you have to spend anyway toward water quality goals.”

3. Measuring the cost savings:

Both Seattle and Portland have to reduce their combined sewer overflows – by law. That costs money no matter what. But according to Jane Bacchieri of the Portland Bureau of Environmental Services, adding in green infrastructure to supplement the pipes and tunnels can reduce those costs.

Bacchieri, the city’s watershed services manager, said Portland’s Tabor to the River project replaced aging and undersized sewer pipes but also added green streets and more trees. Part of the selling point was the city’s cost-benefit analysis showing the greenery offered big-time cash savings.

“If we just did a gray fix it would have cost $144 million,” she said. “By doing a gray and green fix – the pipe work and 600 green streets – it only cost us $81 million.”

The city does modeling that looks at how much water plants can rescue from the city’s water treatment plant, said Bacchieri. “And there’s no question that keeping the water out of the system is cheaper than treating it.”

4. Reducing stormwater fees for helpful residents:

The city of Seattle offers sewer rate reductions of up to 50 percent for property owners that reduce impervious surfaces. It’s not a common policy, Tackett said, “but it should be.”

In Portland, you can get a reduction in your sewer rates by planting trees.

5. Helping residents do it themselves:

Seattle’s Rain Wise program offers tutorials on how to build a rain garden and connects people with contractors who can do the job right.

“It’s a program that folks have just loved because it’s their own choice,” said Tackett. “If you want to participate you can be part of the solution.”

The city of Portland offers residents instructions on how to disconnect the downspouts on their homes and start the rain garden planting process.

6. Footing the bill for rain gardens and eco-roofs:

Seattle offers rebates of $4 per square foot for residents who add their own rain gardens and rainwater collection cisterns. And both Portland and Seattle offer incentives for residents to build eco-roofs.

Seattle started offering $4 per square foot a year ago. So far 1.5 acres of Seattle rooftop in 88 houses have been transformed from gray to green. Portland has been offering grants of $5 per square foot of ecoroof since 2008 and has seen 17 acres of new ecoroofing. The city also offers grants for stormwater projects from a fund that comes from the 1 percent fee the city collects from some developments.

7. Choosing low-maintenance plants:

An important part of developing green infrastructure is choosing the right plants, said Bacchieri.

“The maintenance costs can be higher – it’s not a one size fits all kind of situation,” she said. “You need to look at the geography, the location and the people affected. If we put in a facility and the plants start dying, people are going to call us, so we need to look at planting design. We look at a suite of plants that are able to withstand wet conditions, standing water. We’ve got staff that have looked at the composition of the soil you use, what kinds of plants work best and what plants are going to do the job with less maintenance.”

8. Not doing what Ballard did:

Rain gardens and green infrastructure projects can fail, as they did this year in Ballard, Wash. Lisa Stiffler explained in the Seattle Post-Intelligencer:

“Normally Seattle Public Utilities would have done winter monitoring to understand how wet the ground would get and how water moved through it. The agency would have done an intensive outreach to make sure nearby residents understood and were on board with the project.

In Ballard, the agency cut corners. Test pits were dug at 19 sites to measure how fast the water would drain, but that and other monitoring proved not to be enough.

So a serious problem went undiscovered: the presence of underground spring water and shallow groundwater. Some of the more than 90 rain gardens are actually tapping this water and adding it to the rain runoff to create continually soggy ponds.”

9. Understanding the limitations:

There are lots of reasons cities *aren’t* doing green infrastructure. Green infrastructure is still a pretty new concept, and its benefits aren’t well studied or well understood, according to this report from the Clean Water America Alliance.

Two-hundred agencies polled by the alliance reported the major barriers to green infrastructure are that there aren’t well-defined standards for how to do it, there aren’t good numbers on how much it costs to maintain, how to fund it and how to weigh the risks versus the rewards.

Green infrastructure rules can be a tough sell for developers who are focused on their bottom lines and don’t have to live in the houses they’re building (or pay the ongoing sewer fees), the agencies said. And they requires public education and coordination that take additional public resources. Sometimes, they concluded, it seems like gray stuff is easier to manage.

10. Accepting grayish green

Portland and Seattle both have some of the highest sewer rates in the country, but the reasons cited for the higher price tag aren’t green infrastructure. They’re Portland’s $1.4 billion big pipe projects to control sewer overflows and Seattle’s new $1.8 billion wastewater treatment plant.

Making additional investments in green infrastructure has been “a process” for Portland, said Bacchieri. And it hasn’t completely replaced the need for more gray stuff.

“Portland is certainly ahead of the game in that we’re finishing up a CSO (combined sewer overflow) abatement program, and we pushed hard 15 years ago to be able to use more green infrastructure as part of the solution to CSO issues,” she said. “But we only got so far. We still had to build a big pipe. In order to maintain the capacity and longevity of that pipe, green infrastructure is part of that solution.”

Green infrastructure Natural Resource Defense Council

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