All posts in the topic Moving all flood plain housing (Short link)
Summary
- There are 14 posts — by 8 authors — in this topic.
- Latest post made by Chuck Repke at Jul 07 18:12 UTC
Now that we have extra housing in the city, perhaps we could encourage people
to move off of the flood plain. Especially now with the dikes around the
airport, a flood would quickly climb high. So if we have a policy choice, it
would be best if flood plains housing was slowly being turned into flood ready
parks. Northern Minnesota has been in a drought, however it would only take one
heavy northern rainy spring to create a flood. More unusual weather and more
flooding is predicted. Shouldn't our city policy begin to reflect that? In any
case, if we have choices about selling flood plains homes for $1 to restore
them or simply converting that space to parkland, lets take the parkland
choice.
Grace Kelly nicknamed Kelly
Curmudgeon from Merriam Park
But Kelly, if you moved people off the floodplain, how would you pay off all
the TIF bonds that support all the subsidized housing the city just built on
the floodplain? I refer, of course, to the odious Centex development along
Shepard road.
The Centrex site is no longer in the flood plain. However it will flood
eventually, and more often than stated, and indeed lacks appeal that a
functioning multi use community could have had.
However the Tilsner building also isn't in a flood plain, but should be, (as
well as the areas along Kellogg), and has flooded during the last 15 years.
As for the barge cleaning business, I think if St. Paul wants a class act
along the river that does bring a mixed used as well as, you know, people,
they are going to have to find a way to blend the industrial site look into
something else. I feel Minneapolis has been able to do this along their
river front thru downtown (and upstream and downstream), but we haven't been
able to. Yes it will cost more, but I also don't think the area's real
potential will be realized until that site and similar sites are moved
elsewhere (or adapted)
Its odd to see the river valley look so desert like (no people, little joy).
> The Centrex site is no longer in the flood plain. However it will flood
> eventually, and more often than stated, and indeed lacks appeal that a
> functioning multi use community could have had.
Pat, you're right as usual, but it needs some explanation. The first
floor is built to withstand floods, and the residences are perched above
this wonder of concrete - leaving them just above the 500 year floodplain.
I've never thought that was the greatest solution in the world, but it is
true that they are, technically, out of the floodplain.
If I remember correctly, the 1965 flood was pretty close to the 500 year
line and went to about 710 feet above sea level in Pool 2. That's
everything from the Ford Dam to Hastings.
You can find for yourself just what's in the floodplain with google earth
and that tidbit. What I can say is that this does include great hunks of
the West Side, as well as a number of basements in Lowertown and a fair
amount along the West End. I won't guess what it would cost to move all
of that out, but it's a big number. Very big.
I think the work with Lilydale regional park, FKA simply Lilydale, has
given us a lot of additional water storage in this pool. Pickerel Lake is
a good addition to the community as well. But it would have been nice to
add even more to the river, assuming we learned anything from 1965, 1993,
and the smaller ones in between. Based on the Holman Field project, it
seems we haven't.
I don't think we'll see any more mass clearings as we did after 1965
unless we get another 500 year flood. Based on what I can tell from the
Army Corps ability to predict, we're due for another 500 year flood any
day now. We'll see if that changes any minds.
It might be worth noting that, just a bit south of us, they've had two 500 year
floods within the past 15 years. I also find the notion of "used to be in the
flood plain" a little strange. When did the flood plain move? If we place a
structure in the flood plain on stilts is it no longer in the flood plain? What
was done with the Centex development was no different in principle. If the
garage beneath your home floods but not the first floor have you not been
flooded?
I'd say the Centex development is in the flood plain even though the developers
have taken some steps to alleviate the risk (not eliminate it) by building on
mounds of dirt, just as some people deal with living on a flood plain by
building their homes on stilts.
Well besides being a geological formation of sorts, flood plain has a legal
definition both in St. Paul ordinances and with FEMA. The developers had to
go thru a process to get the site declared to be not in a 'flood plain'. It
was a bit more than mounds of dirt, but basically before the development it
had one elevation (one that would flood during the 100 year river flood
event) and after the development it was either at an elevation above the 100
year event (which is what Centrex folks did) or it was protected by a
permanently maintained flood wall (which is what the folks at the old NSP
plant tried to do but didn't quite, and what the West side did in the 60's).
The ground elevation of the Centrex site is approximately the same level,
and perhaps a bit lower (subject to arguments), as the 1965 event. I've
called it a 200 year event when researching it earlier.
Ya, the place is going to flood. And while it takes a 500 year event, or a
bit more, to supposedly get the first residential floor wet, it will take a
lesser event to get the place abandoned, utilities cut off, and isolated.
Fortunately there are no businesses there, no grocery stores, no theaters,
no retail, and no access so it will only be people living there that will
have to move.
Does anyone have the actual elevations for a 100-year or 500-year "high water
mark" from, say, 35E and Shepherd Road's intersections and then down to
downtown?
Base river elevation is ~209 meters ... I'm curious what the approximate
elevations are within the 100-year and 500-year flood plains.
Find a FIRM [Flood Insurance Risk Map] from FEMA or someone who has one and look them all up. You can order them up online if you have some addresses or have the time to use their clunky online software. Here's the FEMA map service center site: http://tinyurl.com/6yx7nt
The maps on FEMA's site only show 100-year flood plains. (I'm
assuming that somebody who's written about the Centex development et.
al. has some idea of the respective elevations -- at least in an
approximate sense).
I'm particularly curious about the relative difference in the
elevations of the 500-year flood plain compared to FEMA's 100-year
flood plain mapping. From what I can see, Shepherd Road serves as a
"dike" for purposes of the 100-year flood plain and I wonder how far
north/west beyond Shepherd Road a 500-year flood plain would extend.
(GoogleEarth puts the elevations of Shepherd Road at between 220-230
meters around its intersection with Randolph.)
> I'm particularly curious about the relative difference in the
> elevations of the 500-year flood plain compared to FEMA's 100-year
> flood plain mapping. From what I can see, Shepherd Road serves as a
> "dike" for purposes of the 100-year flood plain and I wonder how far
> north/west beyond Shepherd Road a 500-year flood plain would extend.
> (GoogleEarth puts the elevations of Shepherd Road at between 220-230
> meters around its intersection with Randolph.)
The 500 year is right at 710 feet above sea level - I was able to verify
this at the Science Museum, which is just out of the 500 year (and is at
711 or so). The latest version of google earth has elevations in the
center as you pan around.
The 100 year line in pool 2 is about 702 feet above sea level, but I'm
less sure about that. I just remember that the very head of Chestnut is
right on it. Consider that close.
If google earth is giving you ferrin' units like meters, use the figures
216m for the 500 and 214m for the 100. That's all above sea level.
If you can around pool 2 (everything downriver from the Ford Dam) you'll
see that there's a lot of stuff under 710 feet.
Over the years different surveying standards have been used by different
entities. The Corps of Engineer, when talking about the Mississippi River,
refer to a particular datum, referred to as the 1912 adjustment. The rest of
the world, in this area anyway, uses the 1929 adjustment which is about .54'
lower. Almost all discussions now use the 1929 adjustment (but I think the
Corps still uses the 1912 numbers)
Significant floods have occurred in 1870, in 1881; then a gap of 71 years
until 1952, the flood (fifth highest) that devastated the West Side and
turned it from a thriving community into an area used only as an industrial
park; then a gap of 13 years until the flood of record in 1965; a gap of 4
years to 1969, the second highest flood of record; a gap of 24 years to
1993 (6th highest); a gap of 4 years to 1997, the third highest flood of
record; and another gap of 4 years to 2001, to the fourth highest flood of
record.
Some confusion exists on the 2001 event because a temporary gauge was being
used at the time and it had not been calibrated. The 2001 is generally
considered a much more significant event than the 1997 because of the time
span and the double peak that occurred.
At the time I got these elevations they were supplied by the Corps of
Engineers and they are all in the 1912 datum.
At the gage located just upstream of Robert Street the elevations:
. Of a 20 year event would be 703.0
. Of a 100 year event would be 708.3
. Of a 500 year event would be 713.2
. 1965 event would be 710.2
. 1969 event would be 708.7
. 1997 event would be 706.5
When wondering what the elevation would be upstream or downstream you need
to figure in a gradient which changes with different events. Again, using
Corps information for certain mile points or posts on the river I had once
created a manual that listed ground elevations, sewer elevations and flood
elevations for different events for different mile posts along the river. Be
careful citing to anyone (I'm very incautious, and am not careful about who
I cite it too) as it was never double checked by anyone else at the place I
used to work at. It may have been since I left and for all I know totally
debunked.
The elevations listed, as I don't know how they would come out formatted in
your email, are simple listed in order of location, mile post, 5 year event,
50 year event, 100 year event, and 500 year event (all in 1912 datum).
MCES (Pigs Eve) floodwall (836.92), 697.12, 704.85, 706.75, 711.33
Broadway (838.99), 697.76, 705.73, 707.65, 712.30
Robert Street (839.28), 697.99, 706.18, 708.16, 712.92
St. Peter Street (839.59) , 698.17, 706.56, 708.63, 713.63
Chestnut (839.90), 698.32, 706.79, 708.87, 713.90
Elm (840.12), 698.44, 707.00, 709.10, 714.19
High Bridge (840.40) 968.62, 707.28, 709.39, 714.48
West end of west side floodwall (840.32), 698.65, 707.19, 709.29, 714.40
Island Station (841.0), 699.28, 708.21, 710.38, 715.57
Crosby Farm Marina (844.72), 702.09, 711.28, 713.64, 719.40
In the do we ever learn department: I attended the light rail hearing at the
Ramsey County Court House last month. During the pre-hearing show and tell, I
was looking at a diagram of the route to the maintenance yard from the Depot
stop. I mentioned to the keepers of the plan, that the last three times it has
flooded Downtown, several hundred feet of where the track was to be laid was
underwater. Answer: several acres coverd by 7 feet of gravel fill will take the
maintenance site track above flood level.
What a fun thread! I'm hearing from so many people on and off the list.
Pat, while I appreciate your excellent attention to detail, I have to
confess it's hard for me to make sense of just where the 500 year line
meanders up and down - I really didn't know it varied that much. All of
my information has always been at Chestnut St, because I live there. I'm
going to publish what I know along with some excellent additions from the
list.
All of these numbers, again, are either at the location specified or
Chestnut Street. Some are a bit rough, but at least close. It will give
you some idea what's in the path of the Mighty Mississippi should it get a
bit full of itself again.
700.0 Roughly where Holman Field floods (before floodwall)
701.0 Pike Island and the Hopnegs are flooded out.
701.6 Sibley/Jackson at Shepard/Warner starts to flood
702.0 100-Year Flood line at Chestnut St
703.0 Roughly where Lowertown starts to flood
703.5 Roughly where Harriet Island goes under
704.2 The 1993 High-Water Mark at Chestnut St
704.8 Raspberry Island disappears
704.0 Roughly where District Energy cant get shipments in
705.2 The 1997 and 2001 High-Water Mark at Chestnut St
706.9 The 1965 High-Water Mark at Chestnut St
708.5 Riverbend Industrial park floods (not confirmed!)
711.5 500-Year Flood line at Chestnut St
711.6 The Science Museum floods
713.5 Pigs Eye Sewage Treatment Plant shuts down and floods
715.0 Newest condos/apartments flood
716+ --> it only gets worse <--
706.9 The 1965 High-Water Mark at Chestnut St
715.0 Newest condos/apartments flood
So, these apartments were built in the flood plain only 8.1 feet higher than
the highest flood we have ever had in the history of the City of Saint Paul!
Start the investigation its a conspiracy!
So, we are talking about 12 feet of standing water on Kellogg at Broadway
before we have water at these buildings...
What were they thinking...?
JMONTOMEPPOF
Chuck Repke