What baffles me, is how can the powers that be, claim 100 year flood stage as a reason for not building several things, yet, they can put buildings like Baker Center in the actual river bed, to which the natural water level would be the 2nd floor of the building. And the new edition to Stocker, abuts the river bed and is clearly inside the flood zone. Maybe you can answer that with better understanding than I currently possess.
First off, that's a really interesting article.
Loved the photo's.
When they moved the Hocking, the hydraulics/hydrology of the river changed completely.
From a runoff/flooding perspective, the old river channel/bed became irrelevant.
If you look at the current FEMA FIRM Map you can see where the Floodway and 100 Year Flood Zone are, based on the relocated Hocking.
You can even pick out remnants of the old river bed.
The map shows just how far removed they are from a flood zone, based on the relocated river.
With the Hocking moved, water just can't get to the old river bed anymore.
So there's no issue building in it.
As I posted, you can build in a 100 year flood zone, under certain conditions.
In New Jersey, you are restricted by what is called "Zero Net Fill".
You also have to elevate a structure so the lowest "living" ("usable" for non-residential structures) space is a minimum of 1 foot above the 100 year flood elevation.
Any portion of building below that elevation, like a parking garage has to comply with other other restrictions.
There are also certain structures that must be "flood proofed".
The Article is correct, channel relocation is no longer the preferred method to alleviate flooding.
Not because of effectiveness, but other considerations, like land acquisition costs and environmental impact.
In NJ, changing the alignment (straightening) a channel is still widely used.
When it comes to flood alleviation, you have to walk a very fine line between
complying with any/all environmental requirements and effectively reducing flooding and flood damage.
One way New Jersey is dealing with this is by buying flood prone structures, demolishing them and restoring the flood plain.
They call it "Blue Acres".
Green Acres was already taken by a different program.