At 09:02 AM 4/1/2005 -0600, Mike Fratto wrote:
Can someone answer this question?
With a flood wall around Holman Field, the airport will keep dry. However, in order to continue to use the facility you need to access to the airport. Does this mean that as part of this development someone is going to raise the level of the access roads to the airport to the height of the flood wall? If so, wouldn't this actually mean, in essence, a larger flood wall? If you can't get to the airport due to flooding, it doesn't make any difference how dry it is.
There already is an existing floodwall all along the western border of the Airport (which goes from the west side of Harriet Island all the way to east of Highway 52, turns south along the west edge of the airport and cuts back towards the bluff under highway 52 and over the railroad tracks by Eaton Street and West Frontage road. And it is designed for a 500 + year event.
And the access roads to the airport, whether it be an extension of Fillmore/Plato or Eaton Street are already designed to go over the top of that flood wall. For really high floods both of these streets have dirt closures (small dikes) that need to be constructed, but these will be for higher than 100 year flood events and by then the airport, being on the wrong side of the 500 year protection, will be flooded again.
Pat Byrne St. Clair and Lexington Parkway Neighborhood
And as to another conversation by Michael and Jim about the Upper Landing site, yes the site, generally, was raised to be a bit above the elevation of the flood of record, which was in 1965. At first it wasn't because of some miscalculations as to how much the river raises from where the guage was near Robert Street but I think we straigthened them out and they adjusted and added two more feet of fill (guessing as to reason). The main problem is that the garages are below ground, built within what would be high ground water elevations, and need to be designed to be water proof. I recently heard, not verified, that to avoid structural damage because of the forces of this groundwater, that hydraulic plugs were included that were designed to release water into the basement to balance forces instead of structural damage occurring. Unfortunately this would cause all the floor drains to be flooded and the capacity of the sanitary sewer pump station to be exceeded and force it to shut down. And this would leave the area uninhabitable because of lack of service. Also I'm not real sure of the actual elevation of the entrances to the garages, and don't know what river elevation is needed to flood the same basement by overland flow. Again, the same thing with the sanitary sewers would happen. And the prime access to the site is off of new Shepard Road, where at Chestnut and Shepard the design is a bit above the 100 year event, but not above the flood of record.
Still Pat Byrne Still St. Clair and Lexington Parkway Neighborhood.
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