BOARD02598

• Board Meeting Date: 9/18/1974
• Description: Agenda or Table of Contents, Minutes
• Board Meetings - Doc Type: Meeting

I feel that there are a few loose ends in the regulation that ought to
be covered and I will cover these in written comments rather than take
your time now. But for instance, the type of loose end I am thinking'
about is related to the low hazard area which has not been delineated
in some rural area which is about to undergo subdivision. In other
words, only the intermediate regional flood has been delineated at this I
point. I think the model floodp'lain regulation should speak stronger,
let's say to the actions of the county commissioners or the city or
whoever adopts it as to how to handle the situation when it has not
been delineated. You don I t have any defined line and there will be a
lot of jockeying around in the low hazard area even though it has not
been defined. I am sure the purpose of course is that if the low hazard
area has not been defined that there would be no exceptions along that
line. But it seems to me that this should be made quite clear.

This leads to many problems because then after it is defined if the
building is found to be in the high hazard area, you immediately have
a problem and liability for the commission or for the city relative to
giving the permit in a high hazard area and now it is a nonconforming
use~ This can go on and be quite difficult for the local municipality.

I would like to comment very briefly on the low hazard area definition.
I think that many of our streams out in the plains we sort of charac-
teristically think of them as flowing a mile wide and six inches deep.
If we use, and let's say the flow of the velocity is 2.9 feet per
second, the regulation for appearances would tend to indicate that the
floodplain could be pretty well filled up as long as we kept a foot
above the flood profile. However, we all know what this would lead to
if we had a mile wide floodplain and six inches deep and then of course
the channel in the center which carries maybe ten percent of the flow.
What would happen is that the waters would then want to rise creating
new flooding. In other words, flooding people who were not in the
floodplain but now are in the floodplain because we allowed them to
build in a six-inch zone. So I do have a recommendation that would
cover that.

In regard to the low hazard area, I feel that your selection, Mr. Sparks
and the board, of the one-foot depth is very good and it is supportable
by engineering evidence and by experience that when you get in excess
of one foot you are beginning to get into problems of floating trailers,
floating butane tanks, debris and other hazards. I cannot, however,
support the three feet per second. I feel it is too high by approxi-
mately one foot per second. I believe that you will find after studying
it further that a more supportable velOCity for the definition of the
low hazard area would be two feet per second. I think that the three
feet per second will lead to some problems.

In regard to one question that was made regarding to small buildings,
I think Mr. Sparks answered that when he was talking about debris. I
do feel that the small buildings and the miscellaneous things that are
less than one hundred square feet in area are the very things that
cause debris blockage which occurred in the Denver flood of '65 and

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