14d

• Board Meeting Date: 9/17/2008
• Description: Director's Report - CWCB Director
• Board Meetings - Doc Type: Memo

FY 06 Counties: Weld County detailed study work continues to progress. Weld County has
identified levees in the Town of Evans and Severance. Due to these levees, additional work will
need to be completed and an estimated preliminary date is projected for October 2010. Work
continues for Fremont County and Clear Creek Counties. Fremont County will go preliminary in
2008. It was found with Clear Creek County that a Master Drainage plan 100-year flows
significantly exceed that of the effective FEMA flows and that Idaho Springs may not be mapped
showing accurate risk. The State's contractor will be working on updating the hydrologic and
hydraulic study to update the floodplain through Idaho Springs. Clear Creek County will go
preliminary in 2009. The Pueblo County Arkansas River Levee floodplain study is in progress,
finalization is still on hold as data from the City of Pueblo detailed studies are being reviewed by
FEMA. From the Arkansas River analysis it will be determined which sections of the Arkansas
River levee and Wild Horse/Dry Creek levee need to be recertified by the Pueblo Conservancy
District.
FY OS Counties: Mesa County DFIRM is currently in FEMA review and is going preliminary in
October 2008. The Garfield Counties are completed and the County wide project is delayed due
to a USGS study that has been reviewed by Michael Baker Jr., Inc. (FEMA's NSP). The initial
comments from the USGS have been received and are currently being reviewed by FEMA's NSP.
Garfield County is planned to go preliminary in 2008. The Montezuma County DFIRM will go
effective September 28th 2008.
FY 04/03 Counties: All of the Boulder County levees have been identified; The CWCB has
submitted a scope outline for completing the DFIRM work for Boulder County and has received
money. The City of Boulder is still working on determining their approach as to how all of their
levees will be mapped and if they plan to certify all seven of their levees. Once there is an
approach as to how the levees will be mapped and all of the data from the City of Boulder is
received the CWCB can move forward with their effort to complete the Boulder Countywide
DFIRM project. The effective date is still unknown. (Thuy Patton)
CORPS OF ENGINEERS RELEASES DAM SAFETY RATINGS: The Army Corps of
Engineers releases Dam Safety Ratings for two Front Range reservoirs: Cherry Creek, Chatfield and Bear
Creek dams in the Denver area are owned by the U.S. Army Corps (Corps) of Engineers and provide
important flood control benefits. All of the Corps dams across the country are systematically being
evaluated under a new dam safety classification program, known as the Dam Safety Action Classification
(DSAC). This system classifies dams into five classes with class One (I) having the highest priority for
attention and class Five (V) the lowest priority.
Using the latest criteria, Chatfield has received a class Four (IV) rating, and Cherry Creek Dam has
received a class Two (II) rating. The classification for Bear Creek is scheduled to be released in 2009. The
Cherry Creek rating results from the amount of development below the dam and past studies that have
identified a potential for an extreme precipitation event that could exceed the original design capacity of
the reservoir. Such a weather event is called the "Probable Maximum Precipitation" (PMP), which as an
extremely low probability of occurring.
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