[Federal Register Volume 69, Number 189 (Thursday, September 30, 2004)]
[Notices]
[Pages 58412-58414]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-21993]


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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: 
[email protected].

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]
BILLING CODE 3710-62-M