PUB00048

• Year: 1992
• Title: Systems Integration as a Water Supply Source for the Denver Metropolitan Area
• CWCB Section: Water Conservation & Drought Planning
• Author: Hydrosphere Resource Consultants
• Description: Overview of water supply alternatives and suggestion for process to address future water supply needs of the Denver Metro Area
• Publications - Doc Type: Historical

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

DRAFT 8/24/92, Page 8

Cheesman and the development of additional storage on the Upper South Platte would in turn
impact the yields of other alternatives such as Gross Reservoir Enlargement.

A. New Major Water Supply Development Projects

1. Smaller Two Forks

The proposed Two Forks project has been a source of controversy for
nearly four decades, first between Colorado's east and west slopes and,
more recently, between environmental organizations and front range water
suppliers. The primary issues of concern have centered around the
transmountain diversion of additional water from the Upper Colorado River
Basin and the site specific environmental and recreational impacts of the
proposed project on the South Platte River. The alternative of a smaller
Two Forks Reservoir, with an active storage capacity of 400,000 acre-feet,
a firm annual yield of 58,000 acre-feet, and a construction cost of $294
million, was investigated in the Metropolitan Denver Water Supply EIS. The
EIS concluded that the smaller Two Forks would also have significant
environmental impacts and, thus, would probably generate a similar level of
controversy.

Issues to be addressed

Whether or not the EP A veto of Two Forks is sustained in the currently pending
litigation, it appears certain that a project at the Two Forks site, large or small, will cont;nue
to be a source of protracted and bitter dispute for years to come -- unless alternatives for
meeting the growing long term water supply needs of the Denver Metropolitan Area can be
devised and implemented. The EIS, prepared by the U.S. Army Corps of Engineers, found
that a number of other large storage alternatives, including a smaller Two Forks, were
"reasonable and practicable alternatives to the large (1,100,000 acre-feet) Two Forks project."
Other studies during the last eight years have identified major additional water supply sources
that were not included in the EIS but may also be reasonable and practicable in terms of their
ability to supply large amounts of water. However, none of these proposed alternatives would
be free of environmental impacts, and none could be implemented without controversy in the
required permitting process. While a major South Platte River Storage facility continues to be
included in the plans of several metro area water suppliers, there was a clear message from the
Two Forks permitting process that other water supply options including conservation must be
implemented first.

2. New Cheesman

Cheesman Dam is located on the South Platte River to the southwest of Denver near
Deckers and is owned and operated by the Denver Water Department. Cheesman is a gravity
arch masonry dam with a storage capacity of 79,000 acre-feet. The New Cheesman, as
proposed in the Metropolitan Denver Water Supply EIS, would store 743,000 acre-feet and
produce a firm annual yield of 68,000 acre-feet at a construction cost of $610 million. The
project would involve the construction of a new dam approximately 1,500 feet downstrea:n
from the existing Cheesman Dam, a diversion dam and operating reservoir on the North Fork
of the South Platte, and 14 miles of tunnel (11 feet in diameter) from the North Fork diversion
dam to the new Cheesman Reservoir.