Thursday, April 11, 2019

Yes, the Path from the MInto Bridge has Flooded

Again, this is not as important as it at one time seemed, but during planning for the Minto Bridge, the City suggested the path system would be above the level of the 2012 flood, which was another two feet higher than this flood.

Plainly we can now see this is entirely wrong.

It doesn't matter for the usefulness and value of the bridge and path system, but it does matter for the credibility of the City when it seeks to persuade citizens of the value of some expensive plan. Sometimes the City offers deeply misleading, or even outright false, takes in the service of some aim. This makes it hard to trust the City sometimes.

The path is flooded at midday,
on the Minto side of the Minto Bridge.
This crest is two feet lower than the one in January 2012
In a July 2013 FAQ, responding to "I am concerned about flooding of the Bridge and Trail. How is this being addressed in the design?" they said:
The Trail will be located on the top of an existing berm on Minto Island. The edges of the paved Trail surface will be thickened, reducing the likelihood that flood flows will damage the Trail. The area of the planned Trail remained above high water in the January, 2012 flood event. Connecting trails in Minto Brown Island Park do flood, but alternate routes located above the 100-year flood elevation are available. [italics added]
The edges of the path might be reinforced correctly, but in most every other way it is wrong.

The bridge plans showed the path would be
well below the 2012 flood at 29 feet
(comments in red added)
For engineers, it should have been easy to see that the trail as marked on maps and in elevations was not going to be above the level of the Janaury 2012 flood.

And based on a river crest of about 27 feet, the path landing at 26.32 feet would just be underwater - just like the picture at top.

The engineering and surveying was accurate. The information was there for the City to make the right inferences and to present them to the public.

But the City misrepresented the information, in error or by design. Why???

Here are some of the other errors, examples of "alternate routes" that are not at all viable, and would not be viable at high water well below the January 2012 crest.

"Alternate Route" - via Twitter

Also "alternative route":
The is at the main entry drive off of River Road
(the dog park is somewhere
off to the right and a little behind) - via Twitter
The Park starts closing when the river is around 20 feet, nearly 10 feet below the level of the January 2012 flood, and seven feet below our current peak.

This isn't important because the bridge and path system is some key transportation corridor. It's not. People walk and bike in loops from one of the parking lots, and through-travel, though possible and quite pleasant, is rare and rounds to zero as a proportion of the total trips.

But there is a different reason it is important, and that reason is because the City too often plays fast and loose with claims on planning projects, especially for transportation. We saw this a lot on the SRC. This bridge and path project was for walking and biking, and still the City misprepresented facts about it.

Why does the City give us so much unreliable information, information that is false or that deflects widely from a standard of "best available information"?

And when there is uncertainty, why can't we talk more about the range of uncertainty? (We definitely see this in traffic modeling and forecasting.)

Anyway, here's a comparison in the flood levels. The ramp from the Union Street Railroad Bridge down into Wallace Marine Park gives measure that is easy to grasp. One photo is from today, the other is from January 2012. You can see the two-foot difference.

April 11th, 2019 (around 27 feet)

And in January 2012
(Near its peak a little over 29 feet)


Here's another view with better light. It's from an important member of Friends of Two Bridges, and shows how the seasonal closure is regarded with humor and is wholly unproblematic now.

via Instagram

1 comment:

Salem Breakfast on Bikes said...

The river crested at 27.35 feet, and midday today it is at about 21 feet.

The City sent out this update:

Minto-Brown Island Park & its dog park are open but many park trails remain underwater and are closed. The water level remains high at Wallace Marine Park and it remains closed. We hope to open the park in the next few days."