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Imagining the future of landscape planning and design

by Timber Press on June 28, 2017

in Design

At the Oregon Convention Center in Portland, a creeklike system of rock and vegetative swale infiltrates small and moderate storms. Large storm flows are conveyed through the system and discharged to an existing municipal separated stormwater sewer system. Photos by the author.

What does a city in harmony with nature look like? Is there such a city on this planet? Perhaps a more realistic question is what city has the plans and policies in place that will insure its transformation is in harmony with nature.

Lakewood, California: Tomorrow’s City Today

Let’s recount the history of one small city in the megalopolis of Southern California. Can we find something that will help us shape the future, either of a single site or a small community or a large city? By sheer coincidence we have picked the community of my elementary school years.

Tomorrow’s City Today. This was the slogan for a new “instant city” that emerged with 17,000 homes in little more than three years during the early 1950s. A suburb of Los Angeles, Lakewood typified the post-World War II urban sprawl that would eventually engulf the United States. Incorporated in 1954, Lakewood featured suburban design with mostly single-family residential neighborhoods and some higher density residential and commercial developments. It was hailed as a city of the future for its form of governance and urban design.

One of several drainage channels in Lakewood, near my childhood home. Paved access roads run along on each side.

Lakewood Center, a shopping mall, was located in the center of town and yet was not convenient for walking in this spread-out development. With hopes of attracting customers from surrounding cities, the Center originally allocated parking spaces for 10,000 cars. Though the mall had perimeter landscaping, there were few trees within the property, and with nearly 169 impervious acres on site, this would become a stormwater nightmare.

The city streets and major arterials were generously planted with pines, sycamores, oaks, and other trees, but the town’s core was and remains an “asphalt jungle.” There were no freeways at the time and even today only a small eastern section of the city has been cut through with a freeway. Today, Lakewood comprises 9.5 square miles and a population of 80,000. Compared to Los Angeles, with 503 square miles and a population of nearly 4 million, Lakewood may have become the city of our future, but it looks like just another large Los Angeles neighborhood.

The stormwater system is typical of Southern California with concrete channels owned and operated by Los Angeles County. The surface channels range in size from 30 to 90 feet wide and stretch for miles with chain-link fences to keep people out. Street drainage gutters and underground pipes convey runoff to the channels. Most, if not all private properties
drain directly to the streets. From Lakewood Center the channels flow approximately 8 miles through the city of Long Beach to the Pacific Ocean.

A newly constructed creek and overflow wetland for large storm events, Malibu, California.

Topographically, the city is flat with little elevation change. Before development, this land served as an agricultural floodplain, with the Los Angeles River to its west and the San Gabriel River to the east. These two rivers would fluctuate by many miles and sometimes merge in the floodplain. It was this extreme fluctuation of the rivers and streams of Southern California that prompted the development of the various drainage channels.

In 1951, people stood in line to buy a house in Lakewood, my parents among them. From 1951 to 1959 this is the city where I grew up. And from my earliest memories I can envision those drainage channels, which were earthen at that time.

I would often follow my three older brothers to the channels, just a few hundred feet from our house, and as they illegally scaled the fence I would squeeze through the fence posts. We played in the water, hunted for frogs and used the channels as shortcuts around the neighborhood. This was our experience with nature, and for all we knew they were natural creeks.

Yet I would later learn that these were anything but. Few were natural or native to the area. These desolate corridors of wasted water flowed not from headwaters but from excess irrigation, swimming pools, and sometimes stormwater runoff. Occasionally the channels reeked of chemicals used to kill vegetation and on those days we would opt to stick to surface streets. When rains transformed the channels into raging torrents, we had sense enough to stay clear, steered in part by parents’ cautionary tales of children swept away to their deaths.

A new parking lot at a commercial facility in Lakewood, California, uses the landscape to meet stormwater requirements triggered by the redevelopment.

Aside from the trees, Lakewood’s stormwater system was as gray as that of any other city. While landscape stormwater management includes earthen channels, those in Lakewood were little better than pipes. Developers, concerned with preserving as much land as possible for houses, made these channels as narrow as possible. Even the San Gabriel River was relocated and encased in a concrete channel several miles east of its original riverbed. The natural flood plain is no more.

Southern California may have a preponderance of concrete channels, but this method has been used throughout the developed world. However, many cities have begun to see the economic and environmental value of natural streams and are designing drainage channels more like creeks or even restoring those original streams long buried by urbanization. Faced with lawsuits and regulations, Malibu, California, has initiated numerous green infrastructure projects with creek restoration among them.

Natural methods of water conveyance are not really new in some areas, but they are gaining favor in many new places. In many cities, project designers have used surface vegetative swales to convey stormwater. These creeks, swales, and vegetative channels move water while allowing for a fringe of riparian zones that provide additional vegetation as well as habitat needed and welcomed for other living species. This more natural conveyance also permits channels to overflow into flood plains.

Lakewood may have eliminated its flood plain, but many communities have since moved to restore theirs. These decisions may be as much pragmatic as altruistic—once a flood plain, always flood-prone. Over a span of two decades, several hundred homes in the Johnson Creek area of Portland were purchased and eventually removed from a historic flood plain, making the land once again available for (controlled) flooding. We can put nature back into our cities and still have our cities.

“We can put nature back into our cities and still have our cities.”

We buy land to build gray infrastructure. Why not buy land to build back the green infrastructure we displaced—the rivers, streams, wetlands and floodplains submerged beneath our sprawl?

Federal stormwater regulations have affected code requirements in Southern California, and signs of landscape stormwater management approaches have emerged in Lakewood. On a visit in the summer of 2015, I observed a redevelopment underway that included a parking lot outfitted with linear rain gardens and stormwater planters. And, the designers got the site design right! Grading directs all runoff into linear rain gardens placed between the lot and the city sidewalks. Numerous curb cuts facilitate the entry of water as well. The entire frontage landscape space is used for stormwater management and it is a relatively shallow depth, about 6 inches, almost perfect.

The only questionable approach was the use of raised planters to capture roof runoff . Rain gardens designed at grade could have served the same purpose as the planters and at a lower cost. Perhaps site conditions prevented this, or maybe the planters serve some dual purpose not immediately apparent. Nonetheless, the planters support a successfully rendered LSM approach.

This 5-year-old living roof has never been irrigated. Compared to adjacent conventional reflective roof it will last twice as long, manage rain, and insulate the building.

When I dream of the possibilities, I imagine that Lakewood might one day pick a channel-shed, such as the one by my old house. A team that included an LSM-proficient engineer and landscape architect would work with upstream cities, the county, and even the Corps of Engineers (which apparently had involvement in the original construction of the channels). Together, they would prepare a Channel-shed Retrofit Plan to thoroughly apply LSM approaches, while continuing to require the city’s LID and Green Street practices (its terms for stormwater requirements) for new construction and redevelopments.

The goal would be to reduce enough runoff from existing development to allow for the gradual transformation of the channels into more natural creeks or arroyos, more like what was recently done in Malibu and the Headwaters project in Portland. With a few hundred more projects like this traversing public and private lands in the coming decades, those old concrete channels would become natural assets and amenities in the community. Adjacent properties would eventually find the ditch behind the back fence transformed into desirable waterfront.

 

Tom Liptan is a registered landscape architect in Oregon and was the ecoroof technical manager in the sustainable stormwater division of the City of Portland’s Bureau of Environmental Services prior to his retirement. He has researched and developed numerous vegetated approaches (green infrastructure) for rain/stormwater management and has designed, monitored, and maintained many projects, including numerous ecoroofs.

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