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03-12-20 | Feature

South Waterfront Greenway

Portland, Oregon
by Paul Dickow, CPSM, Walker Mac; Photos: Jonnu Singleton ?C?(C) Jonnu Singleton/SWA

Walker Macy and Thomas Balsley Associates planned and designed the South Waterfront Greenway park over a former brownfield in the South Waterfront District, one of the highest density neighborhoods in Oregon. The 1.2-mile Greenway, completed in 2015, extends riverfront access, offers spectacular open space, and restores habitat. It fulfills an important aspect of the district's sustainability mission with a unique approach to waterfront development by weaving habitat restoration together with urban park uses. The innovative, structured riverbank provides both containment of contaminated post-industrial soil and in-water habitat for crucial salmon and other species. Direct water access serves light watercraft users and promotes direct contact with the river. The park's circulation system is tied directly to the urban grid of the new neighborhood. Street alignments are carried all the way through the park, terminating at key overlooks at the river's edge.
This plan shows how the riverbank was formalized to increase access and to better withstand the effects of historical flooding. A formal edge was built against pedestrian walkways and added gabion protection to the bank, which will hold soil in place and allow plant material to take root and enhance this project's abilities to withstand 50 and 100-year flood levels.
Sculptor Buster Simpson was engaged during the design process to develop the art piece, Cradle, which combines wood debris and industrial elements at a key location in the heart of the park. The piece evokes ideas of a once wild river impacted by human influence and the continued relationship between the two.
The innovative engineered riverbank provides both armoring and habitat. This previously contaminated site required significant, integrated remedial design that could provide the necessary capping while still providing substantial riparian habitat, particularly for salmon and migratory birds.
Lighting was provided not just for urban safety, but also to accentuate the sculptural qualities of the landscape.
Coordinated signage welcomes visitors to multiple access points along the greenway with a special emphasis on accessibility.
The greenway is located in a protected section of the Willamette River that offers visitors year-round opportunities for recreation.
Design of the overlooks included materials and forms to remind visitors of the site's industrial past. Steel walls extend over the top of the river bank.

Project Beginnings
In June 2017, the Zidell Marine Corporation launched its final barge into the Willamette River, closing a century of maritime industry, craftsmanship and stories in Portland's South Waterfront District. This highly visible location on the Willamette Riverfront was once a bustling, evolving center of barge building, ship-breaking, and timber conveyance; today, this 130-acre brownfield has become Oregon's highest-density neighborhood. For the last 15 years, this emerging new neighborhood has been a proving ground for new approaches in urban planning, brownfield redevelopment, "beyond LEED Platinum" sustainable design, health research and education, public open spaces, and riparian restoration. South Waterfront Greenway is a 1.2-mile segment of the Willamette Greenway that is a highly visual, activated centerpiece of this new neighborhood as a successful, living experiment in interweaving urban recreation with riparian habitats. It also begins to fill a critical gap in the multi-modal Greenway system, which is accommodating thousands of new bike and pedestrian commuters as Portland has matured into a nationally-known destination for active urbanites. The original master plan for the full South Waterfront Greenway, and its first developed phase, the Central District, was executed by a team led by landscape architects Walker Macy, as prime firm and landscape architect of record, and Thomas Balsley Associates (now SWA/Balsley) as lead designer. This partnership led the project from its early master planning in 2002, to the completion of the 4.3-acre Central District in 2015. The park has become both a focal point of the district and a place to move through, with direct access to the water at the termini of the district's east-west streets and a new segment of the multimodal Willamette Greenway trail. The Central District area has become the "living room" for this vibrant new neighborhood, which consists entirely of apartments and condos, making open spaces cherished places of individual respite and social gathering.

Project Elements
With a high mandate for repair of the extremely impacted, post-industrial riverbank and upland site, the essential challenge was to provide for adequate riparian renaturalization, while still providing visual and physical access to the river itself. The design of the Central District includes two primary areas: an upland urban park that interfaces with the urban South Waterfront District, and the riparian bank. Their closely-knit arrangement allows for an intimate relationship with the water - just footsteps from high-density housing and the multi-modal trails; the park's embrace of the riverbank encourages face-to-face interaction with not only the river, but the wildlife as well, including salmon, heron, osprey and other animals that inhabit the river's edge. Elevated overlooks provide an observational experience of the water, through and over the riparian plants; a ramp leading directly to the water provides a chance to experience the river's edge up close, and is a popular put-in for light watercraft.

The overarching design reaches back through the history of the site, drawing inspiration from historic uses, while working to heal the site - allowing it to once again be a positive contributor to the river's health. The graceful, arcing forms of the park's trails (with separated routes for bicycles and pedestrians differentiated by materials and pavement markings) and lawn shelves create a strong contrast to the glittering, linear high-rises and unique architecture of the district, which form the park's backdrop. The intentional use of heavy timber and weathering steel in contemporary forms recalls the site's industrial past. The riverbank was substantially re-shaped, from low-water habitat to the terraced bank that includes soft stormwater plantings and a 'honeycomb' of concrete planting vaults. These engineered riverbank systems are often not treated as a design opportunity; at the greenway, the 'honeycomb' lends a striking visual quality to the riverbank that is revealed during times of the year when water levels are low. Native and climate-adaptive plants have naturally restorative properties and underscore the regional context. The work of a public artist introduced a thought-provoking environmental piece that highlights man's intervention in the native environment and the Native American history on this site. The materials, landscape forms and public art of the upland combine with the stormwater swales and filter elements along the pedestrian paths to filter and clean the district's rainwater before entering the Willamette River.

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Team List
Landscape Architect of Record / Prime Consultant:
Walker Macy
Design Landscape Architect:
Thomas Balsley Associates (now SWA/Balsley)
Bank Design and Permitting Lead:
Flowing Solutions
Geotechnical / Remediation: Hart Crowser
Civil Engineering: KPFF
Structural Engineering: Grummel Engineering
Electrical Engineering: Reyes Engineering
Lighting Design: Luma Lighting
Cost Estimating: Architectural Cost Consultants
Hydrology: PB Ports
Environmental / In-Water Permitting: SWCA
General Contractor: James W. Fowler Company
Photos: Jonnu Singleton ?C?(C) Jonnu Singleton/SWA

As seen in LASN magazine, March 2020.

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