Yuma East Wetlands, Phases 1 and 2
Landscape Performance Benefits
- Created habitat for 330 species of wildlife, including 2 federally threatened and endangered species and 4 additional species of concern. Observations of the endangered Yuma Clapper Rail increased from <1 to 5 per year, and observations of the endangered Southwestern Willow Flycatchers increased from 2 to >4 per year.
- Reduced the project’s water demand by 49-71% per year compared to other revegetation efforts in this extremely arid region through the use of innovative, site-specific irrigation techniques.
- Achieved 90% survival of more than 300,000 plants. A 90% plant survival rate is excellent in any region, and exceptional in the arid and saline conditions of the lower Colorado.
- Engages and educates over 200 volunteers a year, who in total provide more than 1,600 volunteer hours of assistance with the restoration process annually.
- Hosts 100-150 people annually to celebrate the region’s biodiversity through the annual, week-long Yuma Birding and Nature festival (held from 2001-2012).
- Provides recreational opportunities for approximately 220 people per day during the summer and 130 people per day during the rest of the year. 76% of spring, fall, and winter visitors and 90% of summer visitors swim each day, illustrating the importance of this project in providing the local community with safe, year-round access to the river.
- Employed over 150 people in full- and part-time jobs planning, building and maintaining the YEW project since 2000
At a Glance
Fred Phillips Consulting
Former Land Use
South Levee Road
Yuma, Arizona 85364
$9 million (for construction and maintenance over 10 years)
The first two phases of the Yuma East Wetland (YEW) project restored ecological function and public value to a 350-acre wasteland along the Colorado River near the historic downtown of Yuma, Arizona. The site had been a thicket of invasive salt cedar with high salinity soils, trash, and border security concerns. Intense alterations to the river’s natural flow regime and societal issues separated the local community from the river and from their history. In 2000, a grassroots initiative brought together the Quechan Tribe, the City of Yuma, and private landowners to restore over 1,400 acres of degraded habitat. The land was designated the Yuma Crossing Natural Heritage Area, and the unprecedented community support leveraged over $8 million in federal, state, city, and tribal funding. An ongoing coalition of community members and volunteers have now restored 350 acres of wetland and riparian ecosystems, providing habitat and reconnecting the people of Yuma with the river through new access points, overlooks, and trails.
- Drastically reduced flows in the Colorado River – from upwards of 22,000 average annual cfs at Yuma before the dams to 300-600 average annual cfs after – resulted in the marsh at Yuma East Wetlands completely drying up in 2002. The excavation of over 220,000 cubic yards of sediment created a back channel that returned water flow and healthy ecosystem function to the wetland and restored the historic confluence of the Gila and Colorado Rivers, a culturally significant site for the Quechan tribe. Water control structures at both ends of the channel allow for the management of waters flowing through the marsh.
- Approximately 1,600 acre-feet of water per year from Yuma’s municipal water treatment plant are reused to feed the Yuma East Wetlands, eliminating the need to draw water directly from the Colorado River, thereby avoiding complicated water rights battles. After being used to clean the treatment plant infrastructure, water is delivered to the head of the wetland, where it flows through the area and supports the restored wetland ecosystem.
- In phases one (2004-2006) and two (2007-2009) of the project, a combined 350 acres were cleared of exotic vegetation and replanted with specific plant communities based on local soil and hydrologic conditions. Waste vegetated material was burned to prevent recolonization and to avoid expensive disposal costs.
- Local, native plant materials, including bulrush and Gooding willow, were used to supplement nursery materials where possible, ensuring the genetic integrity of plant species and improving plant survival.
- The over 300,000 native plantings across the 350 acres of restored wetland and riparian habitat have flourished and now provide plant material for other restoration projects, particularly willow cuttings for bioengineering tasks and seeds for plantings. The plants also contribute to the available seed source that propagates the spread of native vegetation passively downstream and elsewhere.
- Irrigation techniques include drip irrigation of one gallon potted plants in areas where water was not readily available and use of carefully timed flood irrigation and seeding to mimic natural processes in areas with water access.
- Bioengineering along the Colorado River bank utilized vegetation (instead of rock or concrete) to stabilize the channel, providing ecosystem services, while preventing bank erosion. Banks were lined with buried willow cuttings and then planted with a range of native species, though predominantly Populus fremontii (Fremont cottonwood), Salix exigua and S. gooddingii (sandbar and Goodding willows).
- More than 2.5 miles of pedestrian trails made of decomposed granite follow existing infrastructure such as levees and canals. The trails connect to the newly renovated Gateway Park to facilitate visitors’ enjoyment of the area through hiking, jogging, birding, and other activities with minimal impact on the restored habitats.
- The Yuma East Wetlands are home to numerous educational and volunteer events, including planting days and the annual YEW Youth Cultural Festival, which began in 2002) and gathers over 80 students from over 12 countries, 4 Indian tribes and 3 communities each year to plant trees, celebrate the healing of the ecosystem, and learn about other cultures.
Water rights and property disputes are extremely sensitive issues in the agricultural regions of the arid Southwest. In addition to ongoing property disputes over land in the Yuma East Wetlands area, the project faced initial opposition from the well-organized agricultural community of Yuma, largely based on misinformation about water rights and the project’s vision and goals. Restoration advocates needed to assure local farmers that the project would be a community asset and would not impact their livelihoods.
The Yuma Crossing Natural Heritage Area Corporation, the landscape architect and other partners garnered support for the Yuma East Wetlands project through numerous public meetings, as well as countless informal discussions with concerned members of the community. Ultimately, community support was instrumental in raising over $8 million in federal, state, city and tribal funding for the effort. Once built, the project was well-received, and every year hundreds of volunteers donate time and money to help maintain the trails and habitats in the Yuma East Wetlands.
- In choosing a planting palette for arid regions, one must consider both soil salinity and depth to groundwater, or plantings are unlikely to survive. By conducting detailed soil and hydrological studies, the YEW designers avoided early problems with plant survival while also conserving water. For example, some areas had such high salinity that most native plants could not survive; in response, designers identified the few native species able to withstand the harsh environment, such as inland saltgrass and alkali sacaton.
- Standard willow planting methods use cuttings and irrigate until roots reach groundwater – a process that can take many years in arid regions. Furthermore, plants have little incentive to deepen their root network when irrigation is being applied from the surface. The YEW designers avoided this scenario by digging holes or trenches and placing willow cuttings as deep as possible, strategically flood irrigating so that water would seep deep into the soil rather than staying near the surface. This method encourages roots to reach groundwater more quickly, reducing irrigation water requirements and maintenance of irrigation infrastructure over the long term.
- For a restoration project of this scale in which such sensitive ecological communities are present, ongoing monitoring and maintenance efforts are essential to project success. Because the Army Corps of Engineer Section 404 permit (RGP 22) requires five years of plant monitoring, the landscape architect developed a monitoring plan and was retained at the beginning of project implementation in 2004 to conduct vegetation monitoring for 12 sites within the YEW. The designer also secured over $180,000 from the Arizona Water Protection Fund to conduct research in 2007-2009 to determine the effect of the Yuma East and Yuma West restorations on the recovery of bird, invertebrate, herpetofauna and mammal communities.
Landscape Architect & Lead Consultant: Fred Phillips Consulting
Consultants & Contractors: Taylorbird Enterprises, Sheppard Wesnitzer Engineering, Ecosystems Management International, JSA Inc., Southwest Biomes, Revegetation and Wildlife Management Center, Southwest Recycling, PG&E Construction, Downriver Productions, Stevens Ecological Consulting, Natural Channel Design, Doug Mellon Farms, Southwest Hydro Systems, I&R Contractors, and Joe Hudson Consulting.
Project Sponsors/Collaborators: Quechan Indian Nation, City of Yuma, Yuma Crossing National Heritage Area, Arizona Game and Fish Department, US Bureau of Reclamation, US Bureau of Land Management, US Fish and Wildlife Service, US Environmental Protection Agency, Yuma Farm Bureau, Arizona Western College, US Border Patrol, Yuma County, Arizona Water Protection Fund, Sonoran Joint Venture, North American Wetlands Conservation Council, Environmental Defense Fund, Bill Ogram, the Headstream family, and the McVey family.
Role of the Landscape Architect
As the lead consultant, the landscape architect conducted initial biological investigations of the site, including vegetation mapping, wetland delineation, topographical surveys and soil analyses, later completing the environmental permitting and planning processes. Another key aspect of the project was building community consensus, including leading meetings with all 16 site owners.
As lead designer, the landscape architect designed the new ecosystem, determined excavation and grading plans, created the pedestrian network and park sites and directed implementation of riparian and wetland restoration. The landscape architect also continued to monitor the wetlands after project completion, studying the vegetation for five years per Army Corps of Engineers requirements, and monitoring wildlife through a grant from the Arizona Water Protection Fund.
Case Study Prepared By
Research Fellow: G. Mathias Kondolf, Professor and Chair of Landscape Architecture & Environmental Planning, University of California, Berkeley
Research Assistant: Zan K. Rubin, PhD Candidate, UC Berkeley
Research Assistant: Shanna Leigh Atherton, MLA-EP Candidate, UC Berkeley
Firm Liaison: Charlie Morgan, Fred Phillips Consulting
Kondolf, G. Mathias, Shannah Leigh Atherton, and Zan K. Rubin. “Yuma East Wetlands, Phases 1 and 2.” Landscape Performance Series. Landscape Architecture Foundation, 2013. https://doi.org/10.31353/cs0540