I'm not sure which version they are promoting now, but at one point, the walls would be a retractable type that would relatively fit in with the current landscaping. I'm not sure how they would cover the roads.
The current plan is for $630 million total cost (some work such as planning and pumps some levies and walls are already done)
The current plan does not include any protection for buildings on May's Island.
The plan includes mostly removable flood walls, but also includes some permanent ones as well as earthen levies in other areas. It also creates a river walk type area along the river with plazas and things of that nature.
For the most part property owners in the flood plains downtown have not been asked to shoulder any of the costs. (Quaker did fund part of their wall, CRST didn't but allowed some savings by constructing the wall during the building construction phase)
Several weeks before the flood when it became apparent that the city wasn't ever going to see any federal funding due to the poor cost metrics associated with the project. There were some suggestions made by council member Ralph Russel. One of those is the creation of a SSMD (Self Supporting Municipal District). Not to toot my own horn but I had Ralph visit my local group when he was running and I made that suggestion to him several years ago.
What a SSMD is a block of property owners that approve to assess themselves extra property taxes for use on public projections within the district. What I had originally proposed was creating 4 SSMD's 2 on each side of the river one for the 100 year flood plain and one for the 500 year. Somewhere around 75% of property owners would have to approve the SSMD to create it.
The thought behind it is that once protection is built these property owners would no longer be required to pay flood insurance premiums because the wall would effectively remove them from the flood plain. So the owners would commit those funds for lets say the next 20 years to help fund the system.
This plan would not cost those property owners anything additional over what they are currently paying.
Since I have no clue how much revenue this would generate I would assume there will still be a funding gap to get from the $280 million the state has committed over the next 15 years and the $630 million price. Once property owners have some funds in the wall I personally would support some kind of funding on the city level for the protection. The previous 2 tax votes failed because their plan was too extravagant and cost way to much compared to the possible damage that could occur from future events. The $5-6 million in temporary barriers proves that point I think.