District 1 Seattle City Councilmember Lisa Herbold shared the results of a seismic report provided by Seattle Public Utilities that points to recommended seismic upgrades across the area. Herbold writes:
"Last week in my committee, Seattle Public Utilities (SPU) briefed us on the seismic report that they released late last year. Coverage by the Seattle Times reporter Daniel Beekman in December reported on the report vulnerability findings and recommendations. The last seismic report was commissioned by the utility in 1990. Since 1990 scientific knowledge and understanding about earthquakes has changed significantly. In 2016 SPU began conducting another study.
In the new report they considered Seattle Fault Zone and Cascadia Subduction Zone type earthquakes, up to magnitude 7.0 and 9.0 respectively. The goal of the study is to incorporate the current understanding of risks into long-term planning for capital improvements to SPU’s water distribution system.
Based on recommendations from the 1990 study SPU has invested $100 million over the last nearly 30 years on discrete seismic updates. However, the new report suggests spending an additional $40 - $50 million in short-term measures in the next 15 to 20 years; and $800 million over the next 50 years for long-term infrastructure improvements, totaling $850 million to improve seismic resiliency.
According to the report, there’s a 15 to 20 percent chance of a catastrophic earthquake - in the next 50 years - similar to the 2011 quakes in Christchurch, New Zealand (6.2 magnitude), and Tohoku, Japan (9.0 magnitude). In both of those instances it took over 45 days to restore water service to the affected areas. The report also stated that there’s an 85% chance of at least one earthquake - in the next 50 years - like the 2001 Nisqually quake that many of us remember.
Another big take-away is that, while previously SPU had begun decommissioning two reservoirs, the report indicated that the reservoirs are needed to provide emergency water. These are the Roosevelt and Volunteer reservoirs. However, even with these two reservoirs Seattle will still be below comparable cities for water access in an emergency. During the committee discussion I asked whether SPU should consider additional ways to increase our water capacity in the event of a catastrophic event so that it more closely aligns with other similar jurisdictions.
The cost, need, and type of upgrades will continue to be a focus of mine, especially when we update the Strategic Business Plan which sets a predictable rate path for six years, and is updated every three years – most recently in 2017. Affordability for ratepayers is top of mind for me even when confronting such necessary infrastructure upgrades.
