(click to enlarge)
Here's a pretty close composite of a summer view with the proposed bridge and a winter view of the flood. The matchlines are very close (check out the faint outline of the crane at the Meridian, which you can see complete below) - call it 95%, maybe even a little better? I didn't quite get enough on the left side, so I overlapped the summer image. In the lower-light gloom, I also had to take the photo with the camera on the railing rather than above it, so the near-side vegetation is a little off - but it's the same set of brambles! It's close enough to give you the idea.
And the idea is, there's no island! The berm on which the bridge and path would land is just barely visible, and I suspect it's only the top of the brambly vegetation that is visible. I bet the land itself on the top of the berm is under water. Certainly the land on each side of the berm is underwater.
Minto Park proper is also underwater.
So unlike the Union Street Railroad Bridge path system, which is still quite a bit above the floodwaters, and appears to have been high enough to stay above both the 1996 and 1964 floods (but not the 1890 and 1861 flood levels in the pre-dam era), the Minto bridge won't connect to land in any meaningful way during floods. And maybe even during regular "high water" it won't be usable.
These are not arguments not to build the bridge. No one says, "look, the soccer and softball fields are underwater! The fields are useless; what a waste of money!" No one says this, or if they do, they are laughed away. It's not a serious argument.
Mostly I still think the similarity shows we are better off thinking of the Minto Bridge as more a recreation facility than a "transportation corridor."
Still, this part of the argument is not as clear as I have supposed. The bridge on State Street where it crosses Mill Creek, between 21st and 19th Streets, flooded; the bridge from River Road to Independence is often closed for high water in the bottom land. So periodic closure for high water does not by itself disqualify something as a "transportation" facility.
But the flood is a reminder that the Minto bridge and path doesn't make connections on any side of the key triangle of homes, jobs, and business. It's a park-to-park connection. It's a recreation facility.
And the crowds on the Union St. Railroad Bridge, most of whom had driven cars to Riverfront Park, just made me wish the City would focus on improving connections to the Bridge across especially Wallace Road and Commercial, and give more thought to connections across Edgewater and Liberty. People should feel free to walk and bike to the bridge, not just drive and park.
Update, February 3rd
Here are two images based on what I believe is the flood level accurate to within 6 inches. The calculation is still uncertain, and I am waiting for confirmation from the City. Still, it passes the sniff test. Correlating the pre-1966 flood gage, which is still in use, and gave a reading of 29 feet during the peak, and correlating it to the 1988 NAVD (vertical datum), I calculate a flood elevation of about 138.5 feet, several feet below the 100-year mark.
The second image shows the entire proposed Minto path and you will want to click to enlarge it. It will show that nearly all of the path would be underwater.
Click to enlarge full path.
Update, February 4th:
This might be the easiest way to summarize my calculations.
Update, Feb 7th:
Well, the river it turns out is not in flood or very high water nearly as much as I feared. Using a table of daily mean river elevations from 1988 on, out of 8539 days of readings, only 142 days showed river elevations over 131 feet (about 21.5 on the graph), which would be the low point of the Minto path (I don't know what elevations there are already in the park, if that path system goes even lower, however). You can see maybe 15 peaks that go over this threshold in the 24 year period. So that's on average a week or maybe two, of high water each year. I was thinking it might be measured in weeks or months rather than days.
I wish the City would discuss this openly, though. I think it's reasonable for citizens to want to know how often they should expect not to be able to use a +/- $7M facility.