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Modeling wind and wave energy to inform a living shorelines flood protection strategy

Arcata, California

Featured image for the project, Modeling wind and wave energy to inform a living shorelines flood protection strategy

(Figure 1) Map of Arcata Bay showing highlighted restoration areas (in yellow), protection zones (red), and proposed new salt marsh living shoreline protection (green) around Arcata Marsh & Wildlife Sanctuary Recreational Area. Map from City of Arcata, Environmental Services.

Description

Arcata is located in northern California on the coast of rural Humboldt County along Arcata Bay estuary. Home to about 17,200 residents, including nearly 7,000 students at Humboldt State University (HSU), the coastal margins of the city were built on historically submerged area currently protected from inundation by dikes and levees. With rising sea levels, Arcata Bay’s shores are at risk to increasing impacts from flooding and higher than average tides.

The city government of Arcata recognizes the pending threats of sea level rise due to climate change. In particular, the city is considering adaptation strategies for the myriad public and private developments potentially affected. The city’s innovative marsh-based wastewater treatment plant is vulnerable due to its location (Figure 1) and is a critical priority for the city. Mitigating the impacts of increased flooding on homes and businesses in the South G Street corridor is also of great importance. Furthermore, preserving, and ultimately transitioning, ecological function and habitats in Arcata Marsh and Wildlife Sanctuary are primary adaptation objectives.

Sea Level Rise Risk Assessment conducted in 2018 modeled sea level rise scenarios in the City’s Local Coastal Program (LCP) planning area. The modeling indicated the effects could be significant. While the South G Street area itself is an elevated structure created by historic fill, higher maximum tides will affect backwater flooding, groundwater elevation, and stormwater runoff rates. Even best-case modeled scenarios will require adaptation and accommodation.

Arcata residents have been engaged in the city’s adaptation planning efforts. Residents have participated in annual king tide monitoring and photo documentation events since 2017. The Friends of the Arcata Marsh, a local non-profit focused on education and outreach around the Arcata Marsh, provides tours, events, and education, some of which have been focused on sea level rise. The city has partnered with Humboldt State University on events. In addition, staff has held several stakeholder meetings, public forums, and study sessions with the Planning Commission and City Council on sea level rise. Arcatans are very engaged in the topic.

Proposed Urban Protection Areas (Click to open full-size image)

Living shorelines, which offer potential benefits for stabilizing sediment while maintaining shoreline migration capacity and preserving valuable habitat areas, are one coastal protection strategy of high interest the city. However, living shorelines are not a ‘one size fits all’ solution for every environment and require comprehensive planning and siting based on factors including elevation, wind fetch and wave energy conditions. The City of Arcata is considering the merits of constructing living shoreline structures around the wastewater treatment plant oxidation ponds in tandem with building “eco-levees” (i.e. gradation between salt marsh/mudflats to upland), recognizing that this would be a temporary solution for shoreline erosion. Fully addressing the risks of rising ground and surface water from sea level rise will necessitate a measured retreat from former tideland areas in the long term.

 

The Project

Arcata is striving to develop a well-researched plan for successfully executing shoreline protection measures between now and a higher sea level future. For this reason, Arcata seeks assistance in investigation of the environmental feasibility of potential shoreline protection options. A partner scientist should be able to synthesize existing information and recommend options to increase resilience and to inform the city’s coastal protection efforts over the next 5-10 years.

An expert is requested to conduct wind and wave energy modeling, and recommend a plan for monitoring Arcata Bay physical parameters. Characterizing local wind and wave energy dynamics would remove one barrier to installation of living shorelines and facilitate efforts to scale up a larger living shorelines matrix around critical areas in Arcata, including bolstering levees near the marsh-based wastewater treatment plant. This work would also build on an existing body of work done related to sedimentation, flood vulnerability mapping, hydrology and sea level rise scenario modeling in Humboldt and Arcata Bay for a more complete picture of how Arcata’s shorelines are changing and where the city government should target construction of stabilizing structures first. Simultaneously, the pilot living shorelines project results will demonstrate on the ground how well the site performs in stabilizing sediment. Modeling completed by the partner scientist should result in a data-driven recommendation to the Arcata government project team to complement the pilot study, and a brief written report for use by the project team.

Completing this work would benefit the overall Arcata community by enabling the city government to move forward confidently in strategically targeting eroding shoreline areas for stabilization, increasing the resilience of wastewater treatment infrastructure, homes, businesses, recreational areas and coastal habitats.

 

Timeline

The project should start by March 2021, meeting monthly as a project team over the course of roughly 12 months. The team will work to refine the outcomes and deliverables with the partner scientist, and then hold check-ins with the partner scientist about once each month throughout the duration of the work. The City of Arcata is eager to move forward in identifying the most feasible options for shoreline protection, to support planning efforts, review of funding sources, and applications for additional grants if necessary. Arcata’s draft Sea Level Rise Policy and LCP Plan are currently being developed, and ideally, this project work would coincide with the LCP plan’s adoption by the city in mid-2021, though this is not expected. Recommendations resulting from this work also have potential to shape the direction of steps toward implementation. A proposal for Ocean Protection Council funding has been submitted to pilot a living shorelines project, which would be conducted alongside this project. The current project work would help leverage future grant funding by laying the groundwork for appropriate placement of stabilizing structures while supporting plans to scale up a living shorelines matrix for Arcata.

About the Community

The scientific partner can expect to work in close communications with David Loya, Community Development Director with City of Arcata, in shaping the overall direction of the project. David’s role in the project is focused on policy and strategic planning. Susan Diehl McCarthy, Community Development Specialist with City of Arcata, is the secondary project lead keeping the team on task. Susan is involved with Arcata outreach and engagement efforts.

Also from City of Arcata government, the team includes Emily Benvie with the Environmental Services Department, who is experienced with current living shorelines work, environmental permitting, and applying for grant funding to implement a living shorelines pilot. Mark Andre, former Environmental Services Director, will likely remain involved as a volunteer, as his knowledge and experience of living shorelines gained prior to his retirement in December 2020 will be invaluable. Additionally, the team includes Netra Khatri and Jess Clifton as representatives from the city’s Engineering Division.

Jeff Anderson with Northern Hydrology Associates brings technical expertise in engineering. Jeff conducted sea level rise hydrodynamic modeling and inundation vulnerability mapping for the 2018 Risk Assessment work for Arcata, and continues to advise the project team as needed.

Project Team

Community Leads

David Loya, Community Development Director, City of Arcata

Susan Diehl McCarthy, Community Development Specialist, City of Arcata

Emily Benvie, Environmental Services Department, City of Arcata

Mark Andre, Former Environmental Services Director

Netra Khatri, Engineering Division, City of Arcata

Jess Clifton, Engineering Division, City of Arcata

Jeff Anderson, Northern Hydrology Associates

 

Community Science Fellow

Morgan Corey is dedicated to the conservation of marine and coastal environments through applied science, management and policy. Currently a Fishery Management Specialist with NOAA and based in Washington, DC, Morgan has experience working toward restoration in the Chesapeake Bay watershed, researching in the Gulf of Mexico and around Lake Erie. She grew to embrace the power of community organizing for improved water infrastructure in Michigan and previously served as a Peace Corps Response volunteer in the Philippines, working with a local government to support the island’s solid waste management, habitat assessments and fish catch monitoring. She holds a M.S. in Coastal Science from the University of Southern Mississippi and a B.S. in Zoology (Ecology and Evolution) from the Ohio State University. Morgan is excited to learn with the Arcata, CA community how nature can make shorelines more resilient to sea level rise.

Scientist Wanted

A scientific partner is needed to bring additional technical capacity and perspective to Arcata shoreline management planning. A local scientist familiar with the Humboldt Bay or California coastal environment is a plus. The partner must be able to get up to speed quickly with the existing body of work on sea level rise in the region. The project team is also open to working with someone from outside California. If possible, the team would like to continue engagement with HSU researchers and other local scientists through this project and the project leads can help facilitate connections.

The following skills and abilities are requested:

  • Must have modeling and geospatial skills needed to work with existing data for modeling physical conditions of wind and wave energy, and familiarity with methods for on the ground monitoring
  • Ability to recommend site-specific living shorelines monitoring approach for evaluating design effectiveness and suitability for physical conditions of site
  • Understanding of coastal processes including geomorphology, geology, shoreline erosion, sediment accretion and stabilization of the land-water interface
  • Ability to synthesize quantitative information, including hydrology data, elevation, sea level rise risk models and flood vulnerability maps, to identify data gaps and recommend data-driven approaches for the city to consider in future living shorelines strategy
  • Knowledge of salt marsh habitat dynamics, ecosystem services, coastal adaptation policy and planning helpful
  • Effective science communication skills, and ability to contribute to resulting communications for public, political and regulatory audiences are desired
  • Thoughtful individual with willingness to listen and sensitive to socio-economic considerations in the city’s adaptation strategy
  • Familiarity with California Coastal Commission, Strategic Growth Council, and other similar bodies in the region helpful

 

Interested in volunteering as a scientist? Apply now!