The City of Astoria has contracted with an engineering consulting firm (HDR) to assist with the update of our Water System Master Plan. The plan will provide a future picture of the City’s water supply needs, required infrastructure to meet those needs, and a plan to achieve those needs over a 50-year time horizon. This will require a review of the existing water system, a conceptual understanding of land use and potential development patterns, and a forecast of future population growth based on the latest Portland State University Certified Population Estimate. The project team will need to project future water demand, review water requirements, develop planning and analysis criteria, analyze the water system including developing a water system model, and develop a capital build-out and improvement plan. The Master Plan Update shall meet all State requirements outlined in the Oregon Health Authority Plan Review Requirements for Master Plans at Existing or New Public Water Systems.
The City of Astoria water system consists of a 3,700-acre City owned watershed, water treatment through a slow sand filter system, water storage through a series of reservoirs, a 12-mile transmission main from our water supply to City limits and a vast network of pipes of varying size, material type and age. The City operates and maintains a total of 75 miles of water lines. Operation and maintenance of this system is funded through water rates. The City also wholesales treated drinking water to multiple water districts located outside of city limits.
The City of Astoria has a population of just under 10,000 with a mix of residential, tourism-based industry and seafood industry. In order to meet system demands, the City relies on surface water from our City owned Bear Creek Watershed. Water system demand currently ranges from about 1.1 MGD to 3.8 MGD that follows closely with the seafood processing season.
The City currently has a Water Supply Study (dated November 1996) and a Water Distribution Plan (dated August 2000). The City plans to combine both documents into one Water System Master Plan Update.
Astoria’s Bear Creek Dam is a 90-foot high concrete gravity dam built in 1912 and raised in 1953. The Oregon Water Resources Department (OWRD) has classified the Dam as a high hazard dam due to the dam’s proximity to human population areas downstream that can lead to loss of life and/or significant property damage resulting from dam failure. The City completed a seismic evaluation of the dam in June of 2016 (prepared by Cornforth Consultants) that determined that the dam is unlikely to fail during a Cascadia Subduction Zone event.
The City has also recently completed a Resilience Study of our 12-mile-long Pipeline Road Water Transmission Main that delivers finished drinking water from our watershed to City limits. The study looked at the geotechnical hazards that would pose a risk to our transmission main due to landslides, erosion, culvert failure and soft subgrade.
TENTATIVE PROJECT SCHEDULE
The City anticipates the following completion dates for the project:
- Master Plan Update & Model – January 31, 2021
- Community Water System Risk and Resilience Assessment – June 30, 2021
- Emergency Response Plan – December 30, 2021
The following project stakeholders have been identified for the project:
- Columbia Memorial Hospital
- Astoria School District
- Astoria Fire Department
- Clatsop County
- Clatsop Community College
- Port of Astoria
- Oregon Infrastructure Finance Authority
- Large Fish Processors
- Large Breweries