By Linda Grand Hayward CivicSpark Fellow

Oro Loma Sanitary District is experimenting with a new innovative project that uses local plants to clean wastewater and provide a barrier against sea level rise. I went with City of Hayward employees to learn more about this unique and experimental project.  As a CivicSpark AmeriCorps Fellow, I am working for the City of Hayward and the Hayward Area Shoreline Planning Agency (HASPA) to help the City plan for and adapt to inevitable sea level rise.  HASPA is a joint powers agency of representatives from the Hayward Area Recreation and Park District, East Bay Regional Park District, and the City of Hayward. Jason Warner, General Manager at the Oro Loma Sanitary District, gave HASPA members a tour of the new and innovative Oro Loma Ecotone project. This pilot project, a horizontal levee, uses vegetation on a slope to process wastewater from the treatment plant and can act as a barrier against flooding and sea level rise. 

Hayward’s shoreline is prone to sea level rise and the State’s latest report suggests that the Bay Area will experience 7.2 inches to 13.2 inches of sea level rise by 2050. This amount of sea level rise will increase the risk of flooding for adjacent shoreline properties and saltwater marshes in Hayward.  The King Tides of today will be the new normal of the future. To address this consequence of climate change, The City of Hayward will need to protect the shoreline by using a variety of adaptation methods. When protecting the shoreline, the City will have to consider the numerous stakeholders and assets, including critical tidal marshes, the Bay Trail, and nearby industrial buildings. The City is currently researching different adaptation possibilities, so we were very excited to learn more about the horizontal levee Ecotone pilot project because it uses natural elements to protect areas inland from sea level rise and flooding.

Not only does the Ecotone project look much nicer than a typical concrete levee, it also serves multiple purposes. Jason started the tour by pointing out the Wastewater Treatment Plant processes an average of 12.4 million gallons per day and serves around 46,000 households. We then started walking on a path where to the right you could see a freshwater wetland that is used for excess storage during the winter wet season. Jason explained that treated wastewater, right before the last step of disinfection, is pumped through this freshwater wetland to remove nitrogen and other nutrients that we do not want to enter the Bay.  

Next, the water is sent to the Ecotone slope that consists of dry native plants. The Ecotone slope consists of 70,000 natural plants in 12 beds that were planted by local volunteers. Oro Loma Sanitary District is working with UC Berkeley to research how well these native plants can remove nitrogen and traces of pharmaceuticals. Wastewater Treatment Plants are not typically designed to remove pharmaceuticals which makes this service by the wetland even more exciting. The experiment is divided into four different combinations of soil type, plant species and watering processes. Researchers are testing the water and soil to figure out what combination is most effective. Jason explained how these plants are working so well at removing nitrogen from the water that they are testing it to see if they can bypass the wetland upstream and just use this dry area for nutrient removal. This slope of native plants is not only making our water cleaner, but it may one day help lessen wave impacts associated with sea level rise. 

Oro Loma is setting an example with this ecological solution that helps treat wastewater and helps protect land from sea level rise. The Ecotone pilot project is currently being tested and monitored but there are still some kinks to work out before large-scale implementation of a horizontal levee. For example, more research must be done to see how we can incorporate tidal habitats along these natural slopes. In addition, Jason mentioned they are currently having trouble pumping large amounts of water into these wetlands. Engineers will have to develop better systems that allow more wastewater to be pumped to make this system more efficient.

 It is important to think about new and innovative ways the City of Hayward can adapt to sea level rise and hopefully, if the Ecotone project continues to be successful, horizontal levees will be part of that solution. HASPA and the City of Hayward are working on developing a plan to adapt to sea level rise and we really enjoyed learning about and touring the Ecotone project. 

If you are interested in seeing this project for yourself or want more information on the project you can visit the Oro Loma Sanitary District website.