Riverine Systems
Rogue River Grants Pass, Oregon, United States
Building a bioengineered wall to protect a city’s water supply. The Grants Pass Water Treatment Facility sits directly adjacent to and above a high bank of the Rogue River that, following a major flood in 1996, was eroding from beneath the facility’s foundation. This erosion threatened the city’s only water supply for a population of nearly 35,000. Follow ing the 1998 initial site evaluation and then development of a detailed hydraulic model, Inter-Fluve, under contract to the City of Grants Pass, proposed four options: no action, a traditional concrete retaining wall, a bin wall, and a bioengineered wall. Criteria for evaluating the alternatives included cost, aesthetics, constructability, long-term stability, ease of permitting, maintenance requirements, and habitat enhancement potential. The team chose the fourth option, a bioengineered, stacked geocell wall. The U.S. Army Corps of Engineers (USACE)–Portland District performed the actual construction of the 150-meter-long, 15-meter-high structure, adapting the bioengineering technology to a project site that challenges the limits of this emerging technology. The geocell wall reduced the risk of a catastrophic chlorine spill from the treatment facility while also fostering the growth of a diverse vegetative margin along the river.
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