Data as the influencer for engineering, partnerships, and policy in addressing

the Ross Island Harmful Algal Bloom


The Harmful Algal Bloom (HAB) in the Ross Island lagoon has been occuring with increasing frequency, and has led to the ODEQ listing of the lagoon as impaired. These blooms are caused by cyanobacteria, which thrive in warm and stagnant where nutrients are available. HABs pose critical risks for environmental and human health. Control of them is difficult because it requires: 1) reducing nutrient availability, 2) preventing stagnant waters, 3) reducing light availability, and/or 4) reducing water temperature. Addressing the HAB at Ross Island is particularly complex due to a number of site constraints. OSU is supporting a broad range of stakeholders in working towards addressing the HAB at Ross Island, including hosting a design charrette, synthesizing current knowledge about the system, and developing hydraulic models of proposed solutions to examine their feasibility and effectiveness.


Ross Island HAB Design Charrette

February 25th at OSU Foundation Portland Center Boardroom (Room 2002)


  • Focus the scope of OSU’s design analyses to be as useful and relevant as possible
  • Facilitate discussion of process for addressing the HAB and ecological uplift in the lagoon.


1:00-1:30 Introductions

1:30-2:00pm: Plenary session

  • Microbiology of HABs (Kurt Carpenter, USGS)
  • Habitat needs of Chinook in the Lower Willamette (Tom Friessen, ODFW)

2:00-2:10: Coffee break

2:10-3pm: Community café

  • Groups rotating through tables for focused, hosted discussion on:
    • Values – What we want to protect and enhance?
    • Alternatives – What solutions should we prioritize and where?
    • Evaluation criteria – How do we evaluate alternatives?

3:00-3:10: Coffee break

3:10-3:40: Community café hosts report back

3:40-4:00: Next steps

Synthesis of Ross Island history, regulations, and science

aerial of willamette river and ross island 1950Ross Island history, ecology, and vision

Bureau of Environmental Services (2018) Willamette Natural Resource Inventory of Site WR19 Ross Island/Oaks Bottom

Houck M, Frank C, Medeiros M, Sallinger B, Faha M, Williams T. (n.d.) Envisioning Ross Island


Cells of cyanobacteria, also known as blue-green algae, contaminate the water in Ross Island Lagoon. A recent algae bloom caused Oregon Health Authority to issue a health advisory.HAB biochemistry and control

Oregon Department of Environmental Quality (2011) Oregon DEQ Harmful Algal Bloom (HAB) Strategy

CSIRO Australia (n.d.) Control Strategies for Cyanobacterial Blooms in Weir Pool

Mitrovic SM, Oliver RL, Rees C, Bowling LC, Buckney RT (2003) Critical flow velocities for the growth and dominance of Anabaena circinalis in some turbid freshwater rivers. Freshwater Biology 48: 164-174.

Bormans Webster (1997) A mixing criterion for turbid rivers

Chinook Salmon at Falls CreekSalmon in the Lower Willamette

Willamette Salmonid Research, Monitoring, and Evaluation Program

Oregon Department of Fish & Wildlife (2005) Biology, Behavior, and Resources of Resident and Anadromous Fish in the Lower Willamette River

Schroeder, et al. (2016) Juvenile life-history diversity and population stability of spring Chinook salmon in the Willamette River basin, Oregon

Friesen et al. (2007) Outmigration of Juvenile Chinook Salmon in the Lower Willamette River, Oregon


Oregon Department of Environmental Quality (2017) Ross Island Sand and Gravel 401 Water Quality Certification

Velocity mapRoss Island hydrodynamics

Nortwest Hydraulic Consultants Inc. (2010) No-rise Analysis for Zidell Property Remediation Project

West Consultants Inc. (2001) Hydraulic and Sediment Transport Modeling For the Willamette River And Ross Island Lagoon

West Consultants Inc. (2002) Hydraulic and Sediment Transport Modeling For the Willamette River And Ross Island Lagoon

West Consultants Inc. (2010) Bridge Hydraulics and Scour Assessment Detailed Report for Proposed TriMet Bridge over the Willamette River Multnomah County, Oregon


Hydraulic models and alternatives analysis