FLOOD10406

• County: Denver
• Community: Cherry Creek
• Stream Name: Cherry Creek
• Title: Agenda Item 11.f Sept. 27-29, 1999 Board Meeting - Report Regarding the Cherry Creek Dam Safety Study
• Date: 9/17/1999
• Prepared For: CWCB Board Members
• Prepared By: Larry Lang
• Floodplain - Doc Type: Project

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Colorado Water Consdrvation Board

Department of Natural Resources

1313 Sherman Street '
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]

STATE OF COLORAIJO

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August 20, 1999

8ill Owens
Cover:nor

Co!. Volz ,
Commander & District J?ngineer- Omaha
U.S. Army Corps of Engineers
217 North 17ti1 Street !
Omaha NE 68102-4978;

Creg L Walcher
Execulive Director, DNR

Peter H. Evans
[)irea<lr, eweB

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RE: Cherry Creek Rieservoir Safety Questions
Dear Colonel V olz:

The recent coordination between your staff and mine in convening a technical discussion
of questions pertaining t9 the Corps' flooding safety concerns at Cherry Creek Reservoir were
very successful. We appreciation your commitment to this process and the integrity it lends to
our relationship for the r~solution of this issue and others.
As a result of thi~ technical discussion and the public presentation which followed,
interested parties in Colorado are much better informed about the parameters within which tht~
! National Weather Service and the Corps have determined Probable Maximum Precipitation
I (PMP) and Probable Mrodmum Flood (PMF) values for this reservoir. Specifically, we have a
greater appreciation for the "worst case" nature of these determinations as well as the data,
assumptions and models ~ed in the process. Furthermore, we recognize that the geographic and
orogragraphic location o~ this reservoir requires site-specific determinations.in which
professional judgment becomes a major element. Since the science involved in these
determinations is comple~ and the regulations don't provide a complete formula, building public
(and congressional) support for any corrective action will require adequate peer review and a
clear explanation of the jUstification.
I do not believe tHat the information, peer review and explanation currently available are
adequate to enable the state of Colorado to support a conclusion that there is a dam safety
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problem that needs to be corrected. However, I do not believe this question should be dropped
and I am in a position to support further analysis and review of the PMP and PMF
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determinations. We will continue our coordination with Bill Miller as soon as he is able to return
his attention to the CherT)[ Creek reservoir safety concern, and hope you will contact me anytime
there is an opportunity fo~ us to help advance this information development and decision making
process. I .

~y~

'J'
J

Peter H. Evans

Director. 1
cc; Colorado Water Conservation Board Members
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Larry Lang I
Bill Miller ;
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L\wctrans\ddWolz Itr CC safety

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