[Federal Register: September 30, 2004 (Volume 69, Number 189)]
[Notices]
[Page 58412-58414]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30se04-54]
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DEPARTMENT OF DEFENSE
Department of the Army; Corps of Engineers
Intent To Prepare a Draft Integrated Feasibility Report/
Environmental Impact Statement for the Chatfield Reservoir, CO, Storage
Reallocation Project
AGENCY: Department of the Army, U.S. Army Corps of Engineers, DOD.
ACTION: Notice.
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SUMMARY: The U.S. Army Corps of Engineers, Omaha District (Corps) is
conducting a feasibility study to ``reassign a portion of the storage
space in the Chatfield Lake project to joint flood control-conservation
purposes, including storage for municipal and industrial water supply,
agriculture, and recreation and fishery habitat protection and
enhancement,'' as authorized under Section 808 of the Water Resources
Development Act of 1986. The
[[Page 58413]]
reallocated storage space would be filled using existing water rights.
The Colorado Water Conservation Board (CWCB) is requesting the
additional storage capacity from the Corps for a consortium of its
users in the Denver metropolitan area. The Denver Water Department
currently controls all the water rights that account for conservation
storage within Chatfield Reservoir. The reservoir serves as the
centerpiece for Chatfield State Park. Preliminary studies considered
reallocating flood control storage for three storage scenarios
reflected by three different raises in the multipurpose pool elevation,
currently 5432 feet above mean sea level (m.s.l.): a rise to 5434 feet
m.s.l., providing 2,900 acre-feet of storage; to 5437 feet m.s.l.,
providing 7,700 acre-feet of storage; and to 5444 feet m.s.l.,
providing 20,600 acre-feet of storage. Operational changes required
with a reallocation of flood storage to joint flood control-
conservation storage would produce effects on water supplies,
downstream flood patterns, recreational opportunities, water quality,
and fish and wildlife habitat.
DATES: Public scoping meetings will be held on:
1. October 26, 2004, 7 p.m. to 10 p.m., Littleton, CO.
2. October 27, 2004, 7 p.m. to 10 p.m., Greeley, CO.
FOR FURTHER INFORMATION CONTACT: Questions about the study elements
should be directed to Mr. Martin D. Timmerwilke, Project Manager, Plan
Formulation Section, Planning Branch, U.S. Army Corps of Engineers, 106
South 15th Street, Omaha, NE 68102-1618, phone: (402) 221-4020, email:
martin.d.timmer wilke@usace.army.mil.
SUPPLEMENTARY INFORMATION: 1. Background. The Corps operates the
Chatfield Reservoir located near Denver, Colorado to provide flood
protection for the greater metropolitan area. The reservoir is located
on the main stem of the South Platte River; Plum Creek also contributes
flow to the reservoir. Congress authorized construction of the
reservoir under the Flood Control Act of 1950. The Corps began
construction in 1967, and dam closure occurred in 1973. The authorized
uses for Chatfield Reservoir are flood control, recreation, water
supply storage, and fish and wildlife enhancement.
Under the Corps' current operating plan, conservation storage is
filled by Denver Water Department water rights and used for municipal
and industrial uses. The State of Colorado, Department of Natural
Resources, Division of Parks and Outdoor Recreation has a park and
recreation lease from the Corps for 5,381 land and water acres,
including the area covered by Chatfield Reservoir. Recreation
facilities at Chatfield State Park include hiking and biking trails,
campgrounds, picnic areas, a stable, boat ramps, a beach, and a marina.
Chatfield State Park receives over 1.5 million visitors annually and
provides habitat for numerous wildlife species. The Corps has also
leased portions of the Chatfield Project property to the Denver
Botanical Gardens for public recreation and to the Colorado Division of
Wildlife for fish production and rearing areas. Three irrigation
ditches located at the base of the dam supply water to users in Aurora,
Englewood and Highlands Ranch.
Population growth within the Denver, Colorado metropolitan area
continues to create a demand on water suppliers. The CWCB, representing
a number of smaller municipal water user groups, requested that the
Corps consider reallocating space to accommodate additional
conservation use. Reallocating storage capacity within the reservoir
requires the preparation of a Reallocation Feasibility Report. The
Feasibility Report will be completed in conjunction with an integrated
environmental impact statement (EIS) developed for the project.
Chatfield Reservoir has a total gross storage of 350,043 acre-feet.
This storage is distributed into four zones defined by elevation. The
inactive zone extends from the bottom of the reservoir, elevation 5377
feet m.s.l. to 5385 feet m.s.l., with a storage volume of 28 acre-feet.
The multipurpose zone extends from 5385 feet m.s.l. to 5432 feet
m.s.l., with a storage volume of 27,018 acre-feet. The flood control
zone extends from 5432 feet m.s.l. to 5500 feet m.s.l., with a storage
volume of 206,729 acre-feet. The surcharge zone extends between 5500
feet m.s.l. to 5521.6 feet m.s.l., with a storage volume of 116,268
acre-feet.
Chatfield Reservoir is managed to maintain the level within the
multipurpose pool from Memorial Day through Labor Day. Denver Water
Department holds all of the rights for the water up to the top of
multipurpose pool, 5432 feet m.s.l. The State Engineer's Office submits
requests to the Corps for releases from the reservoir on behalf of
Denver Water Department. Once the pool rises above 5432 feet m.s.l.,
the Corps is responsible for the management of water in the flood
control pool. The Corps works to reduce the flood control pool as
quickly as possible within the constraints established in Chatfield
Reservoir's Operating Plan. Releases from Chatfield Reservoir are
coordinated with releases from Cherry Creek and Bear Creek reservoirs.
The Corps attempts to limit the releases so the flow of the South
Platte River at the Denver gauge remains less than 5,000 cubic feet per
second.
Operational changes would be required with a reallocation of flood
control storage to joint flood control-conservation storage and would
produce effects on water supplies, downstream flood patterns,
recreational opportunities, water quality, and fish and wildlife
habitat. In determining whether to reallocate storage within the
reservoir and change operational regimes, the Corps must comply with
requirements including but not limited to the Endangered Species Act,
the National Environmental Policy Act, the National Historic
Preservation Act, and the Clean Water Act.
2. Proposed Action. The Corps is studying the feasibility of
reallocating some flood control storage capacity in Chatfield Reservoir
to joint flood control-conservation purposes, which include water
supply. The reallocation is needed to enable the CWCB to provide water
to local users for municipal, industrial, agricultural, recreational,
and fishery uses in response to population growth in the greater Denver
metropolitan area.
3. Alternatives Considered. The Corps, working with the CWCB, has
identified and conducted reservoir routing studies on three alternative
increases in the multipurpose pool elevation for further consideration:
A raise to 5434 feet m.s.l., providing 2,900 acre-feet of storage; to
5437 feet m.s.l., providing 7,700 acre-feet of storage; and to 5444
feet m.s.l., providing 20,600 acre-feet of storage. The three
elevations considered in the preliminary study would be anticipated to
have different levels of impacts on recreational facilities as well as
on fish, wildlife and vegetation resources. The Corps' no action
alternative will also be considered.
The three pool-raise alternatives initially identified would
require changes to the operation of the reservoir, and would have
different effects on the existing recreational facilities and use
levels within Chatfield State Park. If the multipurpose pool is raised
to 5434 feet m.s.l., recreation impacts could be mitigated without
relocating the existing structures. Raising the multipurpose pool to
5437 feet m.s.l. would require expenditures to keep the existing
recreational features operational. Raising the multipurpose pool to
5444 feet m.s.l. would require relocating most of the existing
recreational facilities and infrastructure to other, mostly nearby,
sites in
[[Page 58414]]
Chatfield State Park. These alternatives may also differ in the need
for, and type of, modifications to existing project structures. The
Corps has not yet defined specific operational regimes for the pool-
raise alternatives. Additional alternatives, which could include
different storage volumes and varying operational regimes, could be
developed during the scoping and evaluation process.
The demand for water within a reallocated storage pool would depend
on the holders of the water rights used to fill the storage space.
Potential users fall into one of four groups: Municipal water
suppliers, entities requiring augmentation water, entities concerned
with maintaining minimum instream flows in the South Platte River, and
water users for municipal, industrial, and conjunctive uses. How the
water within the reallocated storage pool would be withdrawn would
depend on the objective of the water users. A preliminary study of user
patterns evaluated five demand scenarios that corresponded to different
target release schedules as follows:
a. Supplying municipal water, with release schedules based on
historic data provided by Denver Water Department.
b. Augmenting out-of-priority depletions, primarily for irrigation.
c. Minimum in-stream flows throughout the year within the South
Platte River.
d. Municipal, industrial, and conjunctive use of storage within
Chatfield Reservoir combined with a groundwater source.
e. Mixed use, where the reallocated storage could be used for a
combination of the above uses.
4. Scoping/Public Involvement. The scoping process will provide
information about the reallocation study to the public and serve as a
mechanism to solicit agency and public input on alternatives and issues
of concern. Two public scoping meetings are currently planned. The
specific locations of the meetings will be provided in news releases
issued at least 2 weeks prior to the meetings. These meetings will be
conducted in an informal setting designed to present information about
the reallocation study and to answer questions and accept comments from
the public. The Corps invites other Federal agencies, Native American
Tribes, State and local agencies and officials, private organizations,
and interested individuals to attend one of the scoping meetings and
provide comments. Scoping comments will also be accepted by mail,
phone, or e-mail during the preparation of the Draft Feasibility
Report/Draft EIS. The Draft Feasibility Report/Draft EIS will be
circulated for public review and comments. It is estimated that a Draft
Feasibility Report/Draft EIS will be completed in 2006.
Candace M. Gorton,
Chief, Environmental, Economics, and Cultural Resources Section,
Planning Branch.
[FR Doc. 04-21993 Filed 9-29-04; 8:45 am]
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