BOARD00178 ‎(2)‎

• Board Meeting Date: 5/23/2007
• Description: Flood Section - Cherry Creek PMP/PMF Analysis - Status Update
• Board Meetings - Doc Type: Memo

STATE OF COLORADO

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Colorado Water Conservation Board

Department of Natural Resources
1313 Sherman Street, Room 721
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
www.cwcb.state.co.us

MEMORANDUM

Bill Ritter, Jr.
Governor

To:
From:
Date:
Re:

Colorado Water Conservation Board Members
Tom Browning, Chief, Flood Protection Section
May 10,2007
Agenda Item 21 - May 22-23, 2007 CWCB Meeting
Cherry Creek Reservoir PMP/PMF Update

Harris D, Sherman
Executive Director

Rod Kuharich
CWCB Director

Dan McAuliffe
Deputy Director

Backg:round
Staff will provide a brief update to the Board regarding on-going work related to the Cherry Creek Reservoir
Probable Maximum Precipitation (PMP) and Probable Maximum Flood (PMF) analyses. The results of the PMP
and PMF studies will provide guidance for the U.S. Army Corps of Engineers (Corps) in their effort to assess the
adequacy and safety of the existing flood control facility located within the Denver Metropolitan area.

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Staff continues to provide technical assistance and monitor progress by the Corps regarding the PMP and PMF
studies. The Corps has completed its detailed review of the site specific PMP study submitted by Applied Weather
Associates on behalf of the CWCB. Final results of the revised studies are not yet available.

In addition, the Corps is required by federal policy to undertake a reconnaissance level seismic study for the facility
as a way of ascertaining risk to the dam caused by future earthquakes that may impact the site. The Corps is seeking
seismic and dam safety experts to participate in a technical advisory role and to review study data prepared for their
seismic report. Work on this effort has not formally begun, but Corps remains in regular communication with Staff
on the matter.

It is anticipated that the PMF study will be completed by Omaha Corps professional staff. The Corps and the
CWCB have developed a work plan and are updating the project schedule for completing the major study tasks.
The ultimate goal in this process is to complete the PMF study with the most reasonable PMP values, and then
develop dam safety recommendations at Cherry Creek Reservoir that are acceptable to local, state, and federal
interests. Depending on the results of the PMF, recommendations may lead to the identification of physical
improvements to the facility for the purpose of public welfare and safety.

Summary
This agenda item is presented for informational purposes only, and Staff is not requesting Board action at this time.

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Colorado Water Conservation Board
Flood Protection. Water Supply Planning and Finance. Stream and Lake Protection
Water Supply Protection. Conservation and Drought PI,anning