FLOOD01718

• County: Montrose
• Community: Montrose
• Stream Name: Uncompahgre River
• Title: City of Montrose Flood Control and Drainage Plan
• Date: 5/1/1981
• Prepared For: Montrose
• Prepared By: Gingery Associates, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

G. TO provide tec~njcal1y accurate and manageabh' floodplain infor-
ration based on detailed mapping for early conversion to the re-
gular flood insurance program.
H. To fornulitte itnd evaluitte altern.-,tivl' flood control and drainage
concepts i1nd determine the most "ccr,or:.ically feasibJeand
prdcticalplan.

Scope of h'ork
ihe scope of work for this study includes the following study U1sks;
A. Reconndissanceand field survey to determine flowp<lths and di-
rections of overland flow escaping from stream channels under
existing conditions.
B. Hydrologic investigation to determine the effect of local urban
runoff on the proposed flood control alternatives.
C. Floodplain determination from IO-year, SO-year and 100-yedr events
under existing conditions.
D. Asse$sment of damages for the IO-year, 50-year and lOO-year floods
and calculations of average annual damage$.
E. Conceptual design of flood control alterrlatives that would alleviate
the flood damages in Montrose.
f. Prcliminilry design of tne selected alternat1ve.
G. Economic itnalysis to determine the benefit/cost ratio for the
selected phn.

Mappinq and Sorv~yinq
Topographic mapping, aerial photography and digitized cross-sections
for this study were provided by the City of ~~ntrose and the Colorado Water
Con~ervation !loar-d in cooperation with tile U.S. Bur-eau of R~clamation. The
I'kll'S were prepared by Aer1al Photo Service, Inc., of Tulsa, Oklahoma. in
December 1977, from aerial photographs taken in June 1977.

".

I
)
1
J
]
J
o
~
o
I
I
I
I
I
I
I
I
I
I

The original map scale is I" - 200' and the contour interval is two
feet. Thcrnaps presented in thi!. report have been reduced to I".
400' to facilitate printing.

The City of Montrose and the Colorado \iater Conservation Board
also furniShed contour mapping of the City prepared by Merrick
and Company, dated November 1965.

A reference monument system has been established in the City of
Montrose to maintitin consistency in ~urveying operations. Using
this system to supplement the topography available from
the above mapping, field surveys ~rere conducted by Gingery
Associates,Inc. This additional information was used toC:eter-
mine flow paths of overland flooding.
Related Studies
A review of existing information and data was completed for the
Montrose study area. Existing infonr.ationincluded the following flood
r-elated studies listed in chronological order;
I. "City of Montrose, Colorado, Oritinage Study Master Plan and Cost
Estimates" revised January 4, 1966 by Merrid and Company.
2. "I'.ontroseArroyo Watershed-Colorado River Basin" by U.S. Soli
Conservation Service. June 1973.
3. "Master Plan Report" City of Montrose, 1978.
4. "Floodplain Infonr.ation and Urban Dritinage Report, Cedar Creek ,
I'Qntrose Arroyo, Dry Cedar Creek, Montrose, Colorado" by Hydro-
Trlad,ltd., April 1979 including Hydrologic and Hydraulic
Technical Addendums.
s. "Flood Hazard Information, Uncompahgl"eRlver, flontr-oseandOlathe,
Montrose County, Colorado," prepared by U.S. Army Corps of En-
gineers,February1980.

."