The book “Sustainable Stormwater Management: A Landscape-Driven Approach to Planning and Design,” published last year by Portland landscape architect Thomas Liptan, with writer J. David Santen Jr., strikes an optimistic note about the future of our cities in an era of climate change.
“…Cities of the future will be garden cities. Not for aesthetics, though beauty will follow as a by-product, but for the energy savings, water management, shelter from extreme heat and precipitation, noise buffers, and perhaps most importantly the habitat and urban wildlife these plants will support. Our cities will come alive with people, plants, and creatures thriving in interdependent coexistences.”
Liptan hopes to change the nature of urban design itself. As a sustainable cities advocate, such change is a vision that I share.
Liptan adds a new term to the sustainable stormwater management lexicon: landscape stormwater management (LSM). No American city has implemented more of these LSM approaches than Portland, where both of the book's authors live. Our city has roughly 7,000 green stormwater facilities in place, including a few downtown.
The facilities not only manage stormwater, they “conserve water and energy, reduce urban heat island effect and thermal gain in waterways, recharge groundwater supplies, create habitat and support biodiversity, buffer noise, and provide a healthier, more adaptive, more resilient infrastructure.” I will add that they make a walk or bike ride more pleasant and interesting, and are cheaper and more effective than pipes.
I first met the author in the early ‘90s, when he gave a presentation for a local builders group on green roofs in Europe. He issued a call for us to start applying green roof technology in Portland. Ultimately, Liptan became the Ecoroof Technical Manager in the Sustainable Stormwater Division of the City of Portland’s Bureau of Environmental Services. Today Tom and I participate together in Portland’s Green Roof Info Thinktank (GRIT). We were early advocates for restoring Portland area streams, a movement that gave impetus to the practices in this book.
The book is not just about Portland and its 7,000 LSM facilities. It’s about a design philosophy that puts water into the landscape rather than into storm drains and pipes. It uses examples of LSM design from all over the world. Although it has lots of information you’d find in a manual—site assessment, site design, construction, inspection, cost considerations, operations and maintenance—it’s style and unusual organization make it far more interesting than most manuals or handbooks.
This green street planter at SE 41st & Clay is one of Portland’s 7,000 landscape stormwater facilities. The Tabor to the River project that includes this street saved the city $63 million and added multiple benefits. Image by PlanGreen, winter 2018.
As a professional who has long-criticized “gizmo green,” I appreciate Liptan’s statement that “a good designer relies on principles of design rather than products.” He won my heart when he exhorts us to “look first to native materials and natural systems” and employ “design with native plants first and foremost.” It’s not immediately apparent to me that many designers in Portland actually do this—so Liptan and I have a lot more exhorting to do. I’m hoping this book and my review of it will help.
The book is organized into two major sections: Landscape Stormwater Design: Water Management from a Landscape Architectural Perspective and Landscape Stormwater Management: Vegetative Approaches to Water Management. The four chapters of the first section cover guiding principles, economics, policy and politics--and are something of an exhortation to the landscape architecture profession that Liptan sees as the potential leader of this movement.
It is true that landscape architects have a jealously guarded stranglehold over specifying plants in commercial facilities in Oregon. As a streams-and-natural-areas-restoration volunteer and native plant/ecology-focused tour leader, I throw up my hands at this stranglehold every time I examine a rain garden or stormwater planter facility in Portland and see mostly over-used, alien ornamental species—some of which are invasive elsewhere. And I’ve also spent much time reporting deliberately planted invasive species.
Sandy Boulevard green street rain garden in Portland's Hollywood neighborhood. Image by PlanGreen.
I now advocate that only those trained, formally or informally, in ecological restoration be allowed to design Portland’s stormwater facilities. Just like most architects get little training in urban design, most landscape architects get little training in plants before receiving their credentials (though the latter seems to be a more tightly kept secret).
The far longer second section contains most of the data, tables, rules of thumb and cautions that you might find in a manual. But with its pleas for further research, rallying cries for creative approaches, page-after-page of captioned photos, and its call to design with nature using native materials, the book goes far beyond a manual.
Chapter 5 covers rain gardens and stormwater planters, green streets, and rainwater harvesting. Liptan barely uses the term “bioswale,” conceding that they are just long rain gardens. Rather he distinguishes between rain gardens with their sloped sides and planters with their vertical structural sides.
Although Liptan devotes only a half-page of text under the heading “Green Street,” he does include 10 pages with captioned photos of green streets. The reader can find more green street commentary in his discussions of Nashville’s Deaderick Street, Seattle’s SEA Street and Ballard Roadside Rain Garden Project, and Portland’s Tabor to the River, Halsey Green Street and Headwaters at Tryon Creek projects. In fact much of the latter half of Chapter 5 is devoted to making green streets work better—covering site assessment, sizing, directing flows, plantings and soils, construction, plumbing, cost considerations, and operations and maintenance (O&M).
Central Library Ecoroof in downtown Portland. Image courtesy of Timber Press.
I’ve long been impressed by Liptan’s minimalist approach: “The ideal LSM design should never need irrigation, pruning, or fertilization.” He cautions that O&M plans must state explicitly how plantings should be managed, otherwise most landscape contractors will default to their standard approach of “spray it, soak it, mow it, blow it away.” Ninety percent of street planters in Portland are not irrigated, resulting in huge O&M savings.
Most of Chapter 6 is devoted to what Portland calls ecoroofs, with Liptan using the more generalized term “vegetative roofs” to appeal to a wider audience. However, he moves through vegetative walls, vegetative planters, trees and vines before returning to research on vegetative roofs and then to their design.
Here he is again minimalist: Simpler vegetative roof designs found in Europe are “as good or better than most North American designs.” I would be disappointed if I didn’t see the Red Cinder Ecoroof design that Liptan developed in Portland explained in the book. It’s comprised of a moisture mat, soil and sedums planted in red cinder mulch. It’s low-cost, low-maintenance, self-sustaining with no irrigation, and adaptable to any roof or membrane system. And it protects the roof membrane, manages stormwater and creates habitat.
Tanner Springs Park in downtown Portland doesn’t really daylight Tanner Creek, just replicates such daylighting. But the nearby nature it brings in is great for education. Image by PlanGreen.
Chapter 7 asks the reader to think about how much impervious surface we really need, then moves on to discuss porous pavement, depaving and stream daylighting. Liptan sees a bright future for buried creeks to reappear in our cities, proclaiming that, “A daylighted stream can be the nexus for the dramatic green transformation of an entire neighborhood.”
Both the daylighting and depaving movements have been led for many years by unpaid volunteers who have formed nonprofits and enlisted more volunteers to get the work done. I’m glad to see Liptan exhorting design professionals to do more in this arena.
Liptan’s is a captivating vision for change in the way we design/re-design our cities. I hope more designers and advocates will take to heart a fragment from the book that is going up on my bathroom mirror: “…the door to creativity stands open. Enter unencumbered by the boxes of conformity, and be amazed.”