Whether the building is rebuilt or just renovated, the fact remains that the site is in a seismic liquefaction zone that can cause classrooms, full of children, to buckle and sink abruptly.

Lum Elementary School in Alameda closed in 2017 after that District decided that liquefaction was too high of a risk for that school. Their FAQ page noted, “Even if portions of the building do not collapse, the classroom exit doors could be damaged and not open, preventing student escape.”

Here is how the MVMS Environmental Impact Report (EIR) describes liquefaction (EIR, pdf page 137): “Earthquake-related ground shaking can trigger a rapid loss of shear strength in saturated, loose, granular soil of low plasticity (liquefaction) or in wet, sensitive, cohesive soil (cyclic softening). Liquefaction and cyclic softening can result in a loss of foundation bearing capacity or lateral spreading of sloping or unconfined ground. Liquefaction can also generate sand boils leading to subsidence at the ground surface…. The Marin Countywide Plan (MCCDA) notes that the campus is in area considered to have very high susceptibility to liquefaction (Figure 7) based on regional studies (Knudsen et al., 2000; Witter et al., 2006).”

What then are the seismic options for the current site?

• Retrofit the foundation – Great idea, this is exactly what the EIR recommends. But this would require soil mixing, soil removal, and all the costs that killed the last plan. [Link]. This is almost certainly not feasible. If it is feasible, we need to see those plans and numbers and we need to see that the relevant State regulators agree and approve. None of that has happened.

• The Superintendent said the District’s Plan is to keep the aging 1970s foundation as-is! We will be surprised if the California Geological Survey leaves a liquefaction hazard unresolved at a school. Can the Division of State Architects approve plans that fail to demonstrate structural safety? The District noted at a recent meeting that the temporary campus portables might require a permanent foundation in order to meet modern seismic standards (incidentally, they aren’t sure they can afford that, so this is another data gap). Given all this, color us skeptical that the District could be required to have a permanent fully-modern foundation for the leased portables, while being allowed to leave the 1970s foundation as-is for the permanent project. This strains credulity and common sense.

Bottom Line

The District should not waste time or money developing any plans until it has this answer from the State regulators. Likewise, the community should not waste energy debating these options either. It’s way too stressful and it’s tearing us apart. We think the odds are that some version of an Edna solution will be the only option that will remain once all the information is in. We could be wrong, of course, but that’s our prediction based on available evidence. Nevertheless, the District seems intent to give the renovation option a go, so the consequences of that project management decision will be entirely on them.