BOARD02099

• Board Meeting Date: 5/20/2002
• Description: CWCB Director's Report
• Board Meetings - Doc Type: Memo

Lany Lang met in Omaha on May 9 with the Corps conceming the studying and modeling of up to a 70,000
AF pool. Water Users have shown a definitive interest and need for the reallocated storage space and are
looking to reallocate the most possible, The CWCB will work to balance an acceptable level of flood
protection, minimal impacts to recreation and maximize the water available for storage for water users,

Brown and Caldwell will work with Denver Water and their P ACSM model to develop demand curves for
water users, It was decided to model typical types of water uses for the reservoir rather than get into the
myriad of possibilities, They are: (1) municipal under a junior water right with a simple release schedule
based on maintaining max cany over storage and releasing during drought years, (2) conjunctive use under a
junior water right with a simple release schedule to: maximize direct use for municipal water supply and
maximize injection to groundwater storage, (3) agricultural use (i,e, Augmentation) under a junior water
right with a simple release schedule with Central and other agricultural users to meet augmentation
requirements and schedules, (4) Greenway (instream flows) under a junior water right to provide a 100cfs at
Bi-City plant from mid June to Mid August. Its is thought that Greenway's request and City of Littleton's
request and the DOW request may serve the same purposes as they are very similar. BC will do its analysis
based on the maximum pool size that the Corps will allow to be studied, Le" BC will not break the max pool
(e,g, 70,000 acre-feet) down into three additional smaller pools for purpose of study, Instead, BC will look
at various combinations of smaller pools which total 70,000 acre-feet and attempt to juggle these to minimize
impacts, A final report is due out in late June from Brown and Caldwell and this in conjunction with a report
from the Recreation Impacts Study will help complete the state's commitments to the Corps for the Reservoir
Reallocation Study,

Denver Water's "Drought Year" Operations at Chatfield - Denver Water's Dave Little contacted us on
May 8 to begin discussing drought year operations at Chatfield Reservoir. A 1979 agreement signed by
Governor Lamm, CWCB Director Felix Sparks and State Parks Director George O'Malley Jr. and the City
and County of Denver is the foundation for our discussion, The agreement 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 agreement states, "The contractor recognizes the importance of the minimum level of 20,000 AF to the
recreation of Chatfield and therefore commits itself to 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. 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 as severe an prolonged drought conditions, as such
drought conditions are reasonably determined by the Colorado Water Conservation Board 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,"

We are investigated the details in the agreement. There is an opportunity to assist Denver Metro Area water
users in a severe drought but special attention will need to be paid to the fishery and recreation opportunities
at Chatfield Reservoir. CWCB staff will meet intemally and with the Attomey General's Office and then
with Denver Water in the near future, CWCB staff will update the board as more develops with this issue,

Boulder Creek ISF Donation, Drought Impacts: On May 7 the City of Boulder issued a press release
calling for stronger voluntary water conservation by residents, The Public Utilities Director has indicated
that "The snowpack in the Boulder Silver Lake watershed is less than it was in 1954, which was the worst
drought year of the 20th century," In fact, snowpack readings and runoff projections indicate this drought

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