SRC Cost Estimate and 40% Contingency Nearly Certain to be Inadequate

On questions about earthquake and seismic resilience, the Q & A makes what looks a little bit like a move for false equivalence. They are shading matters so they don't have to face the question squarely.

In Section 20.c of the Q & A they write (and Category 5 is most hazardous, Category 1 the least) that

• The Preferred Alternative east side bridge landing is primarily Category 3; the western bridge approach is primarily Category 4, transitioning to Category 2 with some Category 3.
• The current bridge locations, east side, are primarily Category 5, transitioning to Categories 4 and 3. On the west side, the bridge landings are primarily on Category 3.

This makes the current bridge locations look worse, right? Category 5 is worse than Category 4. Of course we should build the SRC on those more stable soils!

Section 20.b and 20.c

But when you look at the map - and it is significant the Q & A omits the map and merely references one in a different and hard to find document - the whole flood plain across which the SRC would cross is Category 4. The map is dated 1996, and since then there has been a great amount of gravel quarrying and there may be an additional factor of industrial disturbance to increase these soils' propensity to liquefaction. (It would be interesting too if there is any updated version of the map.) In any case, if distance or area is at all a factor in multiplying odds of an event or multiplying the severity of an event, the larger extent of Category 4 soils make the Preferred Alternative meaningfully more risky than the current bridge crossing sites.

The full map, from the Geological Resources
Technical Report Addendum, Sept 2016

Still, it is true that downtown along Water and Front Streets, extending even to edge of Commercial Street, there is a band of Category 4/5 soils. It may be that the current bridge sites are not as stable as we had thought they might be.

Maybe downtown isn't quite
the "low risk" we earlier thought
(via N3B, adapted from chapt 3.18 of the  DEIS)

So here it may not be possible to consider things a slam dunk any more. Maybe it's a little more ambiguous than that.

But it does not seem like a stretch to say that the SRC is still in a high risk area, and that reinforcing the current bridges still is a better bet - not a certainty, but is a better probability - than building a new bridge at the current Preferred Alternative's location.

If you were placing a sports bet - think about that big football game next week - which would you choose?

Would you bet on the Preferred Alternative? Or would you bet on reinforcing the existing bridges? Betting on the SRC here seems like it is easily the longer-shot and that the odds on the current crossing locations are better.

The "Findings" in the Geological Resources Technical Report Addendum from Sept 2016 should not inspire confidence. It is a tissue of weasel words and hardly constitutes an actual finding. Clearly they are concerned and warning about difficulties discovered during construction, and have written a very evasive and "CYA" conclusion. Even in the final bullet, which presumes "proper geotechnical investigations...proper engineering design" and "mitigation measures," they still can't bring themselves to use a positive verb of certainty or confidence, and hide behind "could." There's a lot of risk and uncertainty hiding in plain sight.

"Could" does so much work here.
Section 5.3 on Findings, from Geological Resources
Technical Report Addendum, Sept 2016

So what about the budget? The Q & A asserts that a 40% contingency will be plenty to cover all the uncertainty expressed in Section 5.3 of the Geological Resources Technical Report Addendum.

Section 9.b in Q & A asserts 40% contingency is plenty

It happens that economist and Editor of City Observatory, Joe Cortright, has compiled a list of large projects ODOT managed and their overruns.

ODOT's recent history of cost overruns on big projects
via BikePortland and Joe Cortright

The one with the most unstable soils, the Pioneer Mountain Eddyville project, was announced at $110 million, and came in over $366 million. But even without unstable soils, large projects at ODOT usually require much more than 40% contingency.

There is no reason to think a 40% contingency would be adequate here. There is every reason to think 40% is way too small. Again, do you bet 40% is enough, or do bet a much larger contingency would be necessary?


No matter how tightly SRC advocates vet a cost estimate with unit pricing, and in the materials for the Work Session there is a giant spreadsheet for your consideration, the framework itself for estimating is broken and misleading. It is by design structured to underestimate costs by a very large margin. It even admits that "the planning level estimate does not specifically site-specific factors, such as contaminated soils, archeological considerations, geological conditions, or geotechnical variations..." The estimate is a SWAG, and there is no evidence to suggest a 40% contingency sufficient to cover for it.

And look! Here's a fresh and local example, just a few months old. This fall the Oregon Transportation Commission had to double the budget for the I-5 Woodburn to Salem paving project. Not all of the doubling is cost escalation; some of it is moving budget from one phase to another, if I recall right. Nevertheless, this is just routine maintenance, not major new construction, and they still are going over budget. At least a third of it is unambiguous "increased roadway construction costs." Here's the summary from SKATS:

Big projects, measured in tens of millions, at ODOT often come in over budget. Very big projects of hundreds of millions never come in near budget.

Even if you think the Preferred Alternative is necessary, there is no reason to think the cost estimates are accurate. On the contrary, there is every reason to think the current estimate wildly underbudgets the likely actual cost of the Preferred Alternative at this site.

Between the long extent of unstable Category 4 soils and the wild underestimate for the Preferred Alternative, there are strong reasons to doubt the wisdom of the SRC as it is currently framed in the Preferred Alternative.

Section 20.a and b: There are no direct answers here!

(Previously see "ODOT's Careless Approach on US20 Project Echoes in Geology Report for SRC.")