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Hyperlocalizing Hydrology in the Post-Industrial Urban Landscape
Kevin Robert Perry

Last year, Kevin Robert Perry won an ASLA Professional Award for a truly innovative stormwater management system he designed for the city of Portland, Oregon. Referred to as the “first of its kind anywhere,” Perry's project replaced the city's combined storm/sewer pipe system with a landscaped curb extension carved out of a portion of the street's parking zone.

In other words, instead of using expensive and high maintenance system to funnel urban runoffs to distant, equally expensive and high maintenance treatment facilities and discharge points, they are instead managed on-site with simple, cost-effective, attractive and environmentally sustainable infrastructure.

Kevin Robert Perry

And here's how it works:

Stormwater runoff from 10,000 square feet of NE Siskiyou Street and neighboring driveways flows downhill along the existing curb until it reaches the 7-foot wide, 50-foot long curb extensions. An 18-inch wide curb cut allows this water to enter each curb extension. Once water is within the landscape area, the water is retained to a depth of 7 inches by a series of checkdams. Depending on the intensity of a rain event, water will cascade from one "cell" to another until plants and soil absorb the runoff or until the curb extensions reach their storage capacity. The landscape system in place infiltrates water at a rate of 3 inches per hour. If a storm is intense enough, water will exit the landscape area through another curb cut at the end of each curb extension and will flow into the existing street inlets. With the new stormwater curb extensions now in place, nearly all of NE Siskiyou’s annual street runoff, estimated at 225,000 gallons, is managed by its landscape system.

And here's the plant list, which unfortunately makes no mention of genetically modified super-phytoremediating neo-plants:

The plants selected for the NE Siskiyou Green Street are primarily Pacific Northwest natives, such as Oregon grape, sword fern, and grooved rush. Adaptable ornamental species such as blue oat grass, boxleaf euonymus, and New Zealand sedge, were also planted because these species are low-maintenance and fit very well in the neighborhood context. All of the selected plant species are low-growing evergreen varieties with varying colors and textures which always provide year-round interest.

This program, of course, required the participation of the local residents to help realize and, once built, maintain it. As it says in the project statement, “the aesthetic appeal and intrigue of the new stormwater facilities creates a community asset that promotes both environmental stewardship and education at the neighborhood level.”

Kevin Robert Perry

Kevin Robert Perry

Kevin Robert Perry

In looking at the pictures and getting glimpses of context, one could mistake that this sort of project can only be successfully implemented in neighborhoods such as NE Siskkiyou Green Street — fairly well-off parts where residents can exert political influence on street renovations or on anything that can affect property values.

Kevin Robert Perry

But what we find absolutely wonderful about Perry's designs is that they can be applied to economically depressed areas, in inner cities or blighted post-industrial towns, whose local governments find themselves unable to maintain basic infrastructural services.

Either due to a federal administration siphoning away public works money into boyish adventures; an erosion of its tax base as a result of the subprime mortgage crisis; industries closing or moving as demanded by globalization; or even post-oil and post-water realities making current stormwater management practices unsustainable — these same local governments see their public works budget depleted and running in the red, resulting in their neighborhoods taken off the grid.

The expected response of residents would be to move. Some do just that but it's often the case that many would be financially unable and so must then contend with a pestilential landscape of failed sewers, stagnant pools and unappealing vegetation.

It is in this context, we believe, that Perry's designs seem most suited for and are critically needed.

We can even now think of one specific place: East Saint Louis, Illinois.

Kevin Robert Perry

In any case, Perry also won an ASLA Professional Award the previous year for a similar stormwater project, also for the city of Portland, Oregon.

It definitely deserves a look.

Kevin Robert Perry
Kevin Robert Perry

And these before and after photos are worth noting.

Kevin Robert Perry
Kevin Robert Perry

So congratulations to Kevin Robert Perry.

Sustainable Stormwater Management Program, Portland, Oregon

Dispatches from a Post-Water Chicago
  • timothy
  • February 19, 2008 at 12:05:00 AM CST
  • its not that I doubt the effectiveness or beauty of this system, but I wonder what the original reasoning for storm drains were in the first place. Surely the ability to do what has just been done has been around for much longer than even the ability to produce storm drains, so why did we switch? There must have been some reason, unless it was just collective foolishness.

  • Alexander Trevi
  • February 19, 2008 at 12:36:00 AM CST
  • Hydrology has been around. You can even say that it started when liquid molecules first formed.

    But applying the principles of natural hydrology into an urban stormwater management system, I think, is fairly new. So there wasn't ever any switch.

    That is, I don't think Rome ever used a system somewhat like Perry's in an urban scale and then collectively decided to build sewers.

    I'd be glad if I were to be proven otherwise.

  • Anonymous
  • February 19, 2008 at 3:41:00 PM CST
  • The original reasoning behind storm drains was to get the water out of sight and out of mind. Storm system designers were not thinking about environmental impacts. As a result, stormwater runoff is now one of the largest sources of damage to urban streams.

    A task force in Oregon looked at what can be done to reduce the impacts of urban runoff, and many of the recommendations have to do with installing more facilities like the ones detailed in this blog entry. Check out the report, "Stormwater Solutions: Turning Oregon's Rain Back into a Resource," at

  • Unknown
  • February 19, 2008 at 4:35:00 PM CST
  • I was under the belief that there were design issues with the SW 12th Avenue Green Street. Specifically the risks of not having a pretreatment sump for sediment capture, the lack of first flush holding capacity and the possibility of the planting soils becoming anaerobic. Has there been any follow-up on the condition and effectiveness of the system?

  • Alexander Trevi
  • February 19, 2008 at 6:31:00 PM CST
  • jack: I don't know the answers to your questions, but they've been emailed to a contact person in the city's Sustainable Stormwater Management Program. Hopefully, they'll respond back here.

    Meanwhile, the project's website has tons of information on Portland's green street projects, including these case studies reports.

    There's a report [PDF] on the first 2 years of the SW 12th Avenue project. Two random findings:

    1) A flow test at this site indicated that the stormwater planters are effective in reducing the peak flow of a 25-year storm event by at least 70 percent.

    2) In the first 2 years of operation, the first two planters filled often with sediment and debris (to a depth of 1-3 inches). City staff removed the sediment by hand with a shovel and rake. The facilities appear to manage much more than the drainage area that was assumed during design. The inlet just upstream of the facility and another inlet at the base of an overpass frequently clog with leaves and other debris, resulting in significant additional flow and resultant higher levels of sediment.

    The report, unfortunately, does not address the problems which you alluded to.

  • Anonymous
  • February 20, 2008 at 3:57:00 AM CST
  • Nice. I've seen examples of projects like this in Hamburg - they appear to have been very popular in the 80s - but never one that was quite so aesthetically pleasing. The plantings are so colorful.

    jack, these things rarely work exactly as planned and seem to require a great deal of adjustment and maintainance.

  • C Neal
  • February 21, 2008 at 10:02:00 AM CST
  • tim - I think that the original rationale for storm drains came from the belief that stormwater is unsanitary: breeds mosquitos, spreads disease, smells bad, etc.

    For most of the history of civilization, urban watersheds were synonymous with sewerage - first we dumped our waste into the nearest stream, and when cities grew to a point where those polluted streams were too unbearable to be around, we buried them and called them 'sewers.' And once the sewers were underground, we just dumped our chamberpots onto the curb and waited for the next rain shower to "flush" the streets.

    I think that the impetus to switch away from storm drains comes from indoor plumbing - which made city streets much cleaner - and the clean water act, which makes it much more expensive for cities to treat relatively clean runoff that gets mixed in with the rest of our sewerage.

  • Alexander Trevi
  • March 11, 2008 at 12:13:00 PM CDT
  • Last month I forwarded jack's questions [see comment #4] to the Sustainable Stormwater Management Program.

    Today, I received a reply from Tim Kurtz.


    "Tim Kurtz here from the Sustainable Stormwater Management Program.

    In answer to jack's questions:

    The SW 12th Green Street consists of four planters in series, so the most upstream planter acts as the sediment trap. As Alexander noted, it must be cleaned out regularly. This is somewhat more time consuming than vactoring out a sediment manhole, but only slightly and we save the cost (both capital and environmental) of installing more concrete infrastructure that needs to be maintained with heavy equipment.

    Based on our performance evaluation, the four planters have the capacity to manage our Water Quality Design Storm (0.83 inches of rain in 24 hours) - meaning there is no overflow to the storm sewer for that event. It does manage the first flush.

    Anaerobic conditions are associated with soils that are saturated for long periods of time. While the facility may saturate for short periods of time during large rain events, the facility infiltrates well (testing indicates least 2 inches per hour even when wet).

    As for effectiveness, we tested the facility twice in 2006 by simulating a storm of almost 9,500 gallons of runoff (equivalent to about 2 inches of rain). The facility retained between 50 and 72 percent of the flow. During particularly intense rainfall, all four planters can fill and overflow to the sewer system. We'll be updating our monitoring report, accessible from our website, around June and it will include information on SW 12th.

    The only issues with the facility have been:

    1) bypassing - or water continuing down the curb and not flowing into the planters. Making runoff take the 90 degree turn from the gutter into the planters is challenging. Gutter depressions, beveled edges, and gutter dams (used at SW 12th) are some potential solutions. The dams work very well for the vast majority of storm events, though some bypassing still occurs during intense rainfall.

    2) plant vigor. The rushes have been so happy, that they're growing 1 ft or more higher than anticipated. They flop over into the sidewalk so they must be trimmed at least once a year.

    3) sediment load. As Alexander mentioned, the larger drainage area caused by blocked inlets upstream results in more runoff - and the sediment it carries - than planned. The large sweet gums on the street contribute lots of debris as well. Sediment was removed 7 times last year compared to a planned frequency of 4 times per year. Most of our facility locations do very well with 4 or fewer cleanings per year.

  • Rombsy
  • May 29, 2008 at 12:53:00 AM CDT
  • "And here's the plant list, which unfortunately makes no mention of genetically modified super-phytoremediating neo-plants:"

    ...or fortunately, depending on your point of view. How about some naturally phytoremediating plants, like water hyacinth, Eichhornia Crassipes, in deeper swales. Or biofilms. Something not requiring genetic modification, is what I'm getting at. Unfortunately, I don't think many native/local plants do this very well.

  • Anonymous
  • July 2, 2008 at 10:13:00 PM CDT
  • What a beautiful and functional project.

    An Eagle Scout just completed installin ga rain garden at Woodward Gardens in Tigard, Oregon.

    There is a little known composting demonstration garden that Metro set up years ago at Mary Woodward Elementary School that is still being maintained. There are three acres of gardens which are spectacular that include rainbarrels, rain garden, drip irrigation, sixteen raised beds, two green houses and a wetland boardwalk to name a few as well as about twenty compost demonstration stations.

  • Anonymous
  • July 18, 2008 at 3:56:00 PM CDT
  • The SW 12th Ave green street is a fascinating project. I visited the site last year and it was the topic of a blog post about designing with water.

    I also looked at a stormwater management system installed on Shotwell Avenue in San Francisco.

    The City of Seattle has initiated a street-level stormwater management project known as SEA or street edge alternatives.

    With three highly functional models I hope that cities will implement one of or some combination of the above strategies. I live in Berkeley, Calif. which is facing a drought and water rationing but most of our winter rainfall is funneled to storm drains.

  • rodrigo morales
  • November 20, 2009 at 11:02:00 AM CST
  • Nice project.

    Could the Sustainable Stormwater Management Program answer, How work the system during the sommer seasson? when the plants requiered more whater and is not enough water available.

    thanks, an congratulations, the blog is very good.

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