FLOOD00067

• County: Alamosa
• Community: Alamosa
• Stream Name: Rio Grande River
• Title: Flood Control Status Report for Alamosa County and City
• Date: 7/1/1987
• Prepared For: Alamosa County
• Prepared By: CWCB
• Floodplain - Doc Type: Project

i
I..
I,
I
I
I
I
I
1-,
f:
I
I
1
I
I
1
I'

Phase IV

a. Construct both the north and south tieback levees.

b. The Muller Engineering Study determined that the most
critical areas were within Phases I and II. In order
maximize State and local resources, the decision was
made to commence construction of Phase I and proceed
upstream to the extent of available funds.

Prior to the initiating construction of Phase I, a formal
request was made to the Albuquerque District Corps of Engineers'
seeking project endorsement and financial assistance for
completion of the project which will provide the community a
100-year flood protection.

Another heavy snowpack in the spring of 1986 caused the Rio
Grande to reach a peak discharge of 4,580 cfs on June 7. 1986.
However, due to the completion of recommended channel Clearing
by the Ci ty of Alamosa Publ ic Works Department and emergency
repairs to the golf course levee, this slightly higher flood
did not result in any significant damages.

During the fall of 1986, the levees on both sides of the
river between U.S. 160 and the D&RGW railroad bridge were
completely rebuilt under Phase I. Without these Phase I
improvements. it is almost certain that failure of the old
levee would have occurred during the 1987 snowmelt flood
season. On May 16, 1987, the gage at Alamosa recorded 5.200
cfs or about a l2-year flood. The river remained in flood
stage through June 16. 1987 with a second flood peak of 5160
cfs on that date. The willow mowing and channel Cleaning
during 1985 saved an estimated $315.000 in potential flood
damages during the 1986 flood peak. The levee improvements in
Phase I during 1986 saved an additional $315,000 in potential
flood damages during the 1987 flood peak. The total savings to
Alamosa residents from flood damages is estimated to be
$630.000. (based on Muller Engineering's "Summary of Flood
Damage Estimates and Annual Flood Risks" figure 2).

The total cost of the project through Phase I is approximately
$1.0 million. The city and the county have obtained another
block grant for the completion of a portion of Phase II in late
1987. It is hoped that the state and local monies expended for
Phase I and II can be used as the required matching funds under
a Corps of Engineers program authorized under the Water
Resources Development Act of 1986 for construction of Phases
III and IV in the near future. The Corps is expected to
complete their reconnaissance report by the end of October 1987.

.
.

viii

I