April 28, 2005

Lake Union park becomes environmental showcase

  • Reworked Cascade Park not only looks better, but is helping manage the neighborhood's stormwater.
    Special to the Journal

    Cascade Park
    Photos courtesy Magnusson Klemencic Associates
    Cascade Park was built in the 1930s with oppressive retaining walls.

    Newly renovated Cascade Park is home to an urban forest and an innovative display of stormwater runoff. Located in the Cascade neighborhood of South Lake Union, the park is the first piece in a planned showcase of restorative urban ecology, an approach that seeks to bring nature and its processes back into urban areas to heal urbanization's negative environmental effects and create more livable communities.

    Reconnecting rainfall from streets and roofs to the nearby shore of Lake Union and celebrating that natural process has been a long-standing goal of the Cascade community. After all, 95 percent of the rain that falls on this neighborhood goes to city sewers rather than the nearby lake.

    That goal is beginning to be realized at Cascade Park, thanks to a collaboration between the Seattle Parks Department, the community, The Berger Partnership, Magnusson Klemencic Associates and area developers Vulcan Inc , Harbor Properties and Pemco Insurance. Rainwater that now falls on the site burbles above-ground down a rocky, twisting creek before continuing on its way.

    The park is only the first phase of a much larger effort to transform the Cascade district into an environmentally sustainable urban neighborhood. Eventually, "eco-streets" will surround the park, and runoff from upstream development sites will be channeled into the new creek and potentially down to Lake Union. In the near term, Cascade Park will help manage stormwater from several nearby sites. More importantly, by artfully displaying the natural but normally hidden process of urban runoff, it calls attention to issues of restorative urban ecology.

    The walls were removed, opening up the park and allowing installation of a creekbed to handle stormwater runoff.

    Simple beginning

    Straddling a full block in the heart of the Cascade neighborhood, Cascade Park was created in the 1930s by the Works Progress Administration. Original construction included restrooms, two wading pools, and massive concrete retaining walls up to 13 feet tall along two boundaries.

    Unfortunately, the walls isolated the park from the adjoining streets, looming oppressively over the sidewalks below. Still, for many decades the park was used regularly: by schools during the day and by fearless city residents at night.

    Many master plans and studies were completed over the years to address a multitude of park concerns, but funding was scarce. The 2000 ProParks Levy finally earmarked $250,000 for Cascade Park, primarily to replace outdated and unsafe play equipment.

    Private sector jumps in

    Word spread about the minimal improvements planned for the park during the customary public involvement process, and the Parks Department was approached with a unique offer from Vulcan, Harbor and Pemco.

    The offer was to pause the design effort for 30 days and allow the partnership to engage the department's design team to study a more ambitious renovation. If something better could be achieved with reasonable additional funding, the partnership would chip in; if not, the original design would be carried out. The Parks Department, with community support, granted the request.

    The design team of Berger and Magnusson Klemencic carried out a 30-day crash development of three grander schemes, which were cost-estimated and presented to the community. The overwhelming favorite, dubbed "Cascade Creek," provided better park access and security by removing portions of the old retaining walls and folding the grade gently to the sidewalks. Even with this loss of "usable" space, the desired park program elements still fit on the site.

    At the same time as the park redesign, Magnusson Klemencic was involved in a separate project to study potential routes for clean runoff to Lake Union. It occurred to the team that the open space created within the park could go beyond paths and plants and be leveraged for the daylighting of runoff within the park — Cascade Creek.

    Eco-neighborhood in progress

    Stormwater runs through the creekbed and eventually finds its way into Lake Union.

    The Cascade neighborhood boasts a wealth of progressive community projects, many of them near the new park. Also located on the park block are the Cascade Neighborhood Center (undergoing an "eco-renovation"), a healing garden, barrels for harvesting rainwater and a P-patch. Two streets near the block are designated "green streets," earmarked by the neighborhood plan for pedestrian enhancements and rich plantings.

    As the confluence of such passionate ecological ethic, the Cascade neighborhood is also a district where broader sustainable practices can be used — and the streetscapes are logical extensions. Given the green light from the partnership and the community, the team designed the streetscapes around the park as extensions of the park itself, allowing the lush forest vegetation to spill into the streets and filter the stormwater prior to it joining Cascade Creek.

    The Cascade streetscapes are inspired by Seattle Public Utility's SEA Streets in north Seattle. However, unlike the suburban SEA Streets, the eco-streets at Cascade will serve a multitude of uses and users unique to the denser urban environment.

    Returning rain to the lake

    Once the concept for Cascade Creek with its eco-street tributaries was established, it was natural to look upstream for additional water and downstream for additional expression. The team identified several potential routes for runoff from upstream projects as well as concepts for leveraging downstream Green Streets and development sites for additional, episodic ecological demonstration. The overall journey starts with REI's water feature and ends at the lake shore.

    At the end of the 30 days, the park went from a square of grass modestly improved with new play equipment, a plaza and pathways to a park district with planned improvements extending into surrounding streets. The 1.3-acre lot was revamped into a 3.7-acre park place — a 275 percent increase! In addition, the entire park-block-street frontage-upstream-downstream continuum contributes to the now much bigger idea.

    Based on this work, the partnership committed an additional $600,000 for Phase 1 development within the park parcel, and pledged to carry out streetscape improvements down the road as projects come online.

    Cascade Park today

    The original ProParks improvements were added to Cascade Park, but the community got a lot more. The revised parkland, with its new creek, meandering paths and footbridge, has renewed the community's identity. "The creek is creating a social element for the neighborhood," according to Berger project manager Andy Mitton.

    Mitton adds that you can find evidence of "urban hikers" stopping to rearrange stones along the creek and that even two days after a rainfall, kids can still find a trickle of water in the creek. The park's grand reopening is scheduled for May.

    What's in store?

    Eco-street elements will be added to the park as each adjacent new development project comes online. Meanwhile, Magnusson Klemencic has been working with surrounding property developers, design teams and Seattle Public Utilities to ensure that clean runoff from upcoming redevelopment projects gets directed to Cascade Creek. Alley 24, the future home of architect NBBJ, will bring the first off-site flows to the creek when it opens in 2006. Planning for the downstream route to the lake is ongoing.

    Drew Gangnes, PE, is director of civil engineering at Magnusson Klemencic Associates. Elizabeta Stacishin-Moura is an urban designer at The Berger Partnership.

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