March 8, 2018
Sustainable Stormwater Management: A Landscape-Driven Approach to Planning and Design
by Thomas Liptan, with writer David Santan, Jr
strikes an optimistic note about the future of our cities in an era of climate change:
Indeed, the 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” (p252)
Primary author, Tom Liptan, is hoping to change the nature of urban design itself. As a sustainable cities advocate, such change is a vision that I share.
Liptan adds yet another term to the sustainable stormwater management lexicon: landscape stormwater management. No American city has implemented more of these LSM approaches than Portland, Oregon (where they both live—as does this reviewer). Portland has roughly 7,000 green stormwater facilities in place—including a few in its downtown! They 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”(p18). I will add that they make a walk or bike ride more pleasant and interesting and they are cheaper and more effective than pipes as well!
I first met primary author, landscape architect, Tom Liptan, in the early 90’s 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’s Bureau of Environmental Services (BES). Today we participate together in Portland’s Green Roof Info Thinktank (GRIT). He and I were early advocates for restoring Portland area streams—a movement that gave impetus to the practices in this book.
This book is not just about Portland and its 7,000 LSM facilities. It’s about a design philosophy that puts the water in the landscape rather than storm drains and pipes. And 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 makes it far more interesting than most manuals or handbooks.
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 that—so Liptan and I have a lot more exhorting to do. I’m hoping this book and my review will help.
Sustainable Stormwater Management 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 something of an exhortation to the landscape architecture profession that Liptan sees as the potential leaders 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 about 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 spent much time reporting deliberately planted INVASIVE species in the past.
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 they get their credentials—though the latter seems to be a more tightly kept secret.) Liptan admits this later in the book: Addressing the engineering, architecture and landscape architecture disciplines: “Water, soil and plants as stormwater management elements are new territory and we all have a lot to learn”(p249). “Good designers are not born but educated. . .Better education for designers and city review staff can reduce the waste of money and space.” (p250) Portland would do well to reward and learn from those of us who agree with Liptan.
The far longer second section, Landscape Stormwater Management: Vegetative Approaches to Water Management, has 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, this book goes beyond a manual.
Chapter 5—Water-Accepting Landscapes—is the chapter that covers Rain Gardens and Stormwater Planters, Green Streets, and Rainwater Harvesting amongst other topics. Liptan barely uses the term bioswale conceding that it is like a long rain garden. Rather he distinguishes between rain gardens with their sloped sides and planters with their vertical structural sides. Besides that there are three types of either system: 1) infiltration landscapes, 2) partial infiltration landscapes, and 3) flow-through landscapes.
Although Liptan devotes only a half page of text under the heading “Green Street” he does have ten 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, Ballard (Seattle) Roadside Rain Garden Project, 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 on Site Design is devoted to making green streets work better—covering such areas as site assessment, sizing, directing flows, plantings and soils, construction, plumbing, cost considerations and operations and maintenance (O&M). (Although I understand “The intent is to focus on the outcome of the approach rather than a specific type of implementation. . .,” I found this organization a bit confusing.)
I’ve long been impressed by Tom 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: “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. (However, as a Green Street Steward in downtown Portland, last summer I was begging nearby retailers to water the downtown planters I steward so that they wouldn’t lose any more plants.)
Most of Chapter 6—Vegetative (Living) Cover of Impervious Surfaces—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.
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. 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. “The sedums with the red cinder retard colonization by other plants for many years,” maintains Liptan. Some additional recommendations he makes for vegetative roofs: 1) some kind of mineral mulch if not red cinder—for both moisture retention and shading the soil; 2) integrate solar panels on your roof so the plants can benefit from the shade; 3) manage solar reflections on vegetation where possible—one solution is to cover dead plants with a thin layer of rock to protect the soil and perhaps allow some plants to return.
Chapter 7 asks the reader to think about how much impervious surface we really need then moves on to discussing 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 non-profits 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 too 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.”
Mary Vogel is a CNU accredited planner and founder of PlanGreen, a Woman Business Enterprise in Portland, OR that has paddled upstream for years to bring ecosystem services to excellent urban design. After achieving on-the-ground restorations and some important policy accomplishments in several of Portland’s and the region’s long-range plans pro bono, she would like to get paid work—perhaps outside of Oregon where she can best use her skills.