Ellis Creek Water Treatment Facility, 2001
Working as a member of the Carollo Engineers design team, Johanson helped create a new water treatment facility. By overlaying art, public access, sewage treatment, habitat restorations, and agriculture, she embedded major urban infrastructure within living nature. Her design has been credited with “re-inventing art and reforming civil engineering”. The project includes natural systems to treat sewage, allowing millions of gallons of water to be reused. Johanson used the form of the endangered Salt Marsh Harvest Mouse to create the shapes of the polishing ponds, which contain islands that direct the flow of water and provide nesting habitat for birds. Other plantings support local wildlife. An additional 230-acre (0.93 km2) area of tidal wetlands was acquired for the park and wildlife sanctuary. This multi-purpose landscape provides more than 3 miles (4.8 km) of walking trails for educational programs, nature study and tourism. Petaluma Wetlands Park coincides with a $150 million dollar sewage treatment facility, while also serving as a highly visible model for converting sewage into recycled water, which is stored in a deep reservoir at the end of the “mouse’s tail”.