BOARD02224

• Board Meeting Date: 9/27/1999
• Description: Flood Section - Platte River Basin Issues - Report Regarding the Cherry Creek Dam Safety Study
• Board Meetings - Doc Type: Memo

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Colorado Water Conservation Board

Department of Natural Resources
1313 Sherman Street
Denver, Colorado 80203
Phone: [phone]
fAX: [phone]

STATE OF COLOMDO

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MEMORANDUM

Bilt Owens
Governor
GregE. Walcher
Executive Director, DNR
Peter H. Evans
Director, ewes

TO:

Colorado Water Conservation Board Members
1V
Larry Lang L-.,

FROM:

DATE: Septemberl7,1999

SUBJECT: Agenda Item l1.f September 27-28, 1999 Board Meeting--
Report regarding the Cherry Creek Dam Safety Study

BACKGROUND

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On February 5 and 17, 1999, the Corps of Engineers, Omaha District, conducted public hearings
on the darn safety study for the Cherry Creek Dam and Reservoir. The public hearings attracted
much public concern and raised many issues and questions regarding the study findings. The
Board has also received many questions. The Board responded to these questions and concerns
by conducting a basin tour and discussions at its March 29-30, 1999 Board meeting. The Board
made a recommendation to staff to seek legislative authorization and funding to perform a
technical review for the Probable Maximum Precipitation (PMP) and Probable Maximum Flood
(PMF) values. The language in Section 16 of the CWCB Construction Bill 99-173 provides the
authorization and funding to seventy five thousand dollars ($75,000). On July 21,1999, the
Corps of Engineers, in cooperation with Colorado Water Conservation Board, conducted a
formal technical discussion with a panel of meteorological and hydrological experts that were
jointly selected by the Corps and the Board. The panel heard testimony from the Corps and the
National Weather Service (NWS) regarding the PMP models - HMR's study procedures and
pararneters.

Following the formal presentations by the Corps and NWS, a technical discussion was conducted
for 36 topics regarding the "Site Specific Probable Maximum Precipitation Study for the Cherry
Creek Drainage in Colorado" dated July 12, 1995. Most of the discussion topics reached an
answer of "No consensus by the group". It should be noted that one desenting vote would result
in the no consensus answer. The findings of the July 21, 1999 review is presented in a
Summary Report entitled "Cherry Creek Darn Safety Study, Summary Report, dated August 5,
1999".

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