HomeMy WebLinkAboutA001 - letter from Iowa State, request for floodway change Iowa State Water Resources Research Institute
I OWA STATE Ames,
town Engineering Building
1 1 �T V T Ames,Iowa 50011
Ll l V I E R S ITY Telephone S 15-294-8921
September 17, 1979
Mr. Arnold Chantland Mr. Ron Wooldridge
Director, Public Works Planning Commission
City of Ames City of Ames
Depot Annex Depot Annex
Ames, IA 50010 Ames, IA 50010
Gentlemen:
Re: Request for floodway change, for College Creek outlet
channel, for the Elwood Drive Extension; and possible need
for additional left bank levee work, along the east bank
of the Squaw Creek, south of Lincoln Way
We are continuing to assist in developing the Elwood Drive Extension
project, including the proposed tie-back levee from the Elwood Drive
Extension westward to Wallace Road on the south side of College Creek.
This letter is to alert you to two additional details that need to be
considered.
The first is the need for requesting that the City of Ames,
through the City Planning and Zoning Commission and the City Council,
and possibly with additional coordination of Iowa State University,
request the floodway lines for College Creek be adjusted by the Corps
of Engineers and the Federal FEMA group, to correspond with our pro-
posed levee alignment. The floodway line shown at the recent meeting
In the City Council Chambers indicated that a flaired floodway was
being proposed downstream from Wallace Road as the stream crosses the
floodplain to the east to the Squaw Creek channel. We would like to
have the floodway boundaries adjusted so that the south floodway line
follows the south bank of the stream, to the Elwood Drive Extension
location. Further, the floodway line on the north side of College Creek
be adjusted so that, commencing at the west of the tennis court west
of Wallace Road, the floodway line perhaps be moved to the north bluff
line past the tennis court and across Wallace Road, and then be con-
tinued eastward to the new Elwood Drive culvert across College Creek,
a flaired expansion can then be indicated east of the Elwood Drive
Extension to Squaw Creek channel, from the new culvert location. This
request needs to be considered and transmitted both to the Corps of
Engineers and FEMA so appropriate revisions can be made prior to thr
adoption of the floodplain zoning ordinance by the City of Ames, and
the adoption of the maps correspondin-; to this.
Mr. Arnold Chantland
w ,
Mr. Ron Wooldridge -2- September 17, 1979
The second item concerns the fact that as we propose a levee on
the south side of College Creek and as we extend Elwood Drive northward
to Sixth Street, we may obtain some adverse comments from the property
owners that are located on the east side of Squaw Creek, south of Lincoln
Way. We have a small area lying just north of the South Fourth bridge
which was flooded in 1975, and for which some amount of flood protection
might be needed. I am certain it would be desired by the property
owners in this area, considering the ISU encroachments to the west.
Therefore, I'm wondering if we have excess materials coming from the
13th St. extension, above and beyond which will be required for the
Elwood Extension and College Creek tie-back levee, that perhaps we
should plan to deposit some of this in a low levee that would extend
from the high fill deposits at the northwest abutment of the So. 4th
St. bridge, and moving westward and northward on the back side of the
lots until we reach the higher ground existing in those lots that lie
just south of the water pumping station at the Lincoln Way site. ,I
don't believe that the levee would have to be over 4 to 6 feet high in
this area, although we would have to check the elevations and the
flood profiles that we have. The levee grade should slope from Elev.
74 at L-Way to Elev. 70 at So. 4th St. bridge. It would appear that
if we could use some of the waste material and to obtain the landowners
permission to deposit levee material and build a small levee onthe
back side of these lots, along the east bank of Squaw Creek, it would
serve to protect a flood prone area about which we are concerned. As
part of this project, the storm sewer outlet in this area would have
to be gated, with a wet well. Then we could thereafter, during high
runoff periods, propose that a temporary pump be brought in to pump
from a wet well. to the river, in case it begins to rain behind the
levee. This is needed, unless we can provide additional ground storage
to accomodate a reasonable amount of stormwater storage during the
short flood periods we have experienced on Squaw Creek.
We would be willing to work with you on either one of these
projects at your request. Please let us know if additional informa-
tion is needed.
Yours very truly,
Merwin D. Dougal
Director, ISIdRRI and
Professor, CE
MDD ee
cc: William Whitman, ISU
Wayne Gieselman, INRC
Gar.v McClure, FFNA, Kansas City
Chuck Farnham, Floodplain Management Supervisor
Corps of Engineers, Rock Island
Harris Seidel, City of Ames
Terry Sprenkel, City of Ames