FLOODC00297

• County: Jefferson
• County: Arapahoe
• Title: Chatfield Reallocation Study: Chatfield Reservoir Drought Declaration 5/8/02 - 1/26/03
• Date: 5/8/2002
• Prepared For: Jefferson County / Arapahoe County
• Prepared By: US Army Corps of Engineers/CWCB
• Floodplain - Doc Type: Correspondence

STATE OF COLORADO

Colorado Water Conservation Board

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

TO:
FROM:
DATE:
RE:

MEMORANDUl\J/
CWCB Members V. r
Larry Lang, Chief, Flood Protection Section
July 15, 2002
Agenda Item #11 - Chatfield Drought Declaration

Bill Owens
Governor

Greg E. Walcher
Executive Director

Rod Kuharich
eWeB Director

Denver Water contacted the Board on May 8, 2002 to discuss drought operations at Chatfield
Reservoir. The Board received a drought declaration request from Denver Water by letter dated
May 28, 2002, which letter is attached.

There are two 1979 agreements regarding the CWCB administration of storage space in Chatfield Reservoir. First, an
agreement was executed between the State of Colorado and the Corps of Engineers regarding reservoir operations.
Secondly, an agreement was executed between the State of Colorado and Denver Water regarding the management of
the conservation pool, which is at elevation 5432. The second agreement dated April 3, 1979 was signed by Governor
Lannn, CWCB Director Felix Sparks, State Parks Director George O'Malley Jr. and the City and County of Denver
specifically addresses the drought conditions. It is the second agreement that is the foundation for our discussion. The
rgreement sets the principles for the operation of the reservoir with respect to fill dates, conservation pool, storage
space, recreation pool, and Denver Water's operations.

The April 1979 agreement states, "The contractor (Denver Water) recognizes the importance of the minimum level of
20,000 AF to the recreation of Chatfield and therefore commits itselfto use its best efforts operate the reservoir at this
minimum level during said months. The board believes that it is possible to maintain the reservoir at this minimum
level through the appropriate months, except in periods of drought or under circumstances beyond the control of the
contractor" .

Dan McAuliffe
Deputy Director

"Because of seasonal variations in the available water supply and evaporation rates, the goal of maintaining 20,000 AF
of water in storage every year may not be continually attainable and the amount of water in storage may be allowed to
fluctuate as those conditions require, but not above elevation 5,432 feet or below elevation 5,423, except in severe and
prolonged drought conditions, as are reasonably determined by the Colorado Water Conservation Board and may
require the Contractor unavoidably to cause the level of storage to decrease below elevation 5,423 feet in order to
satisfy its charter obligations to provide municipal water supply."

The Board staff finds that 2002 is year four of an extended drought condition period. The 2002
Water Year may become the worst in the state's history, even more severe than ]934, ]954, or 1977.

Denver Water has a drought plan dated February 2002. The plan is based on three levels of drought, each of which is
triggered by the actual or expected storage reservoir levels on July I of any year:
Drought Level Trigger
Mild Reservoirs are less than 80% full
Moderate Reservoirs are less than 60% full
Severe Reservoirs are less than 40% full