[Federal Register: September 30, 2004 (Volume 69, Number 189)]
[Notices]
[Page 58414-58415]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30se04-55]
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DEPARTMENT OF DEFENSE
Department of the Army; Corps of Engineers
Notice of Intent To Prepare a Draft Environmental Impact
Statement for the Proposed San Clemente Dam Seismic Hazard Remediation
Project--Carmel Valley, Monterey County, CA
AGENCY: U.S. Army Corps of Engineers, DoD.
ACTION: Notice of Intent (NOI).
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SUMMARY: The U.S. Army Corps of Engineers (USACE) has received an
application for Department of the Army authorization from California-
American Water Company (CAW) to deposit approximately 3,200 cubic yards
of fill material into wetlands and other waters of the U.S. in
association with remediating the safety hazards of an existing Dam on
the Carmel River. This application is being processed pursuant to the
provisions of Section 404 of the Clean Water Act (33 U.S.C. 1344) and
in accordance with the National Environment Policy Act (NEPA) of 1969
(42 U.S.C. 4321 et seq.). In accordance with NEPA, USACE has determined
that the proposed action may have a significant impact on the quality
of the human environment and, therefore, requires the preparation of an
Environmental Impact Statement (EIS). A combined Environmental Impact
Report (EIR)/EIS will be prepared with the USACE as Federal lead agency
and the California Department of Water Resources, San Joaquin District
(DWR) as the State lead agency under the California Environment Quality
Act (CEQA). The basic purpose of the proposed actions is to provide Dam
safety. The overall project purpose is to have San Clemente Dam meet
current standards for withstanding a Maximum Credible Earthquake (MCE)
and the Probable Maximum Flood (PMF) while providing fish passage at
the Dam; maintaining a point of diversion to support existing water
supply facilities, water rights and services; and minimizing impacts on
CAW rate payers.
DATES: A public scoping meeting for this project will be held on
November 4, 2004, from 6:30 to 8:30 p.m. at the Rancho Canada Golf
Club, 4860 Carmel Valley Road, Carmel Valley, California. A public
agency scoping meeting for this project will be held on November 9,
2004, 10 a.m. to 12 p.m. at the same location. You may mail comments
to: Phelicia Thompson, U.S. Army Corps of Engineers, Regulatory Branch,
333 Market Street, 8th Floor, San Francisco, California 94105-2197.
FOR FURTHER INFORMATION CONTACT: Phelicia Thompson, 415-977-8452, or
SUPPLEMENTARY INFORMATION:
1. Background: Approximately 2.4 million cubic yards of sediment
have accumulated behind San Clemente Dam since it was constructed in
the early 1920s. Engineering studies of San Clemente Dam were conducted
in the 1990s to evaluate seismic safety at the request of the
California Department of Water Resources Division of Safety of Dams
(DSOD). These studies concluded that at the maximum water surface
elevation of 537 feet (the height of the Dam's crest), the Dam might
not be stable under the MCE. The Dam could suffer severe structural
damage leading to the potential loss of the reservoir during a MCE. In
addition, under the PMF the Dam could overtop and the downstream
abutment area would be susceptible to excessive erosion, leading to a
risk of Dam failure. Based on these findings, DSOD has required that
the San Clemente Dam be brought into safety compliance to withstand
seismic loading from a MCE on nearby faults and safely pass the PMF.
2. Description of the Proposed Action: Dam Strengthening. CAW has
proposed to meet seismic safety needs for the Dam and protect against
the effects of a PMF by thickening the downstream face of the Dam with
concrete. A concrete batch plant would be installed on-site to
manufacture the concrete needed. Sediment accumulated behind the Dam
would be left in place. However, minor sediment removal may occur to
ensure proper functioning of the existing water supply intake serving
the upper Carmel Valley Village area. Water in the reservoir may need
to be lowered to reduce loading behind the Dam (depending on sediment
levels). Inflowing streams would be diverted around the work area and
the plunge pool at the base of the Dam would be dewatered during the
Dam thickening. This proposed action also includes replacing the
existing ladder with a new fish ladder compliant with existing
[[Page 58415]]
National Marine Fisheries Service (NMFS) and California Department of
Fish and Game (CDFG) criteria to provide fish passage. A tower crane
would be staged at the base of the Dam to move construction materials
from the batch plant to the Dam face and fish ladder. Access to the Dam
would be improved by building a new road along the east side of the
Carmel River, between the Old Carmel River Dam and the base of San
Clemente Dam. The Dam thickening project would take an estimated four
years to complete.
3. Reasonable Alternatives: In accordance with the requirements of
Section 15124 of the State CEQA Guidelines and 40 CFR 1502.14,
reasonable alternatives to the proposed action will be evaluated in the
Draft EIR/EIS as listed below:
a. Dam Notching Alternative. This alternative would meet the need
to reduce seismic safety risks by notching the Dam. The action would
reduce the mass sufficiently to avoid catastrophic failure of the Dam
during a MCE event. Notching would also be of sufficient size to
prevent overtopping of the Dam during the PMF. The gates, piers and
walkway at the top of the Dam would be removed and the Dam would be
notched to an elevation of about 505 feet in the area of the present
spillway bays. Sediment in the reservoir would to be removed down to
the level of the notch. A new intake structure would be constructed to
allow the Dam to continue serving the upper Carmel Valley Village area.
A new access road would be constructed to connect Carmel Valley Road to
the Carmel Valley Filter Plant, to bypass the Sleepy Hollow community
and to improve safety for large construction equipment. In addition,
road access from the filter plant to the Dam would be improved. The
existing primitive road from the Old Carmel River Dam to the base of
San Clemente Dam would be rebuilt to an elevation above winter flood
levels. Both the Carmel River and San Clemente Creek would be diverted
around the reservoir and Dam site and the reservoir would be dewatered
each year during construction. Accumulated sediment would be removed
from behind the Dam over two seasons by excavation with heavy equipment
and transported from the reservoir by truck or via a conveyor belt
system to a disposal area near the Carmel Valley Filter Plant. The
existing fish ladder would be rebuilt compliant with existing NMFS and
CDFG criteria to accommodate the lowered Dam elevation. The Carmel
River channel in the inundation zone would be restored. The Dam
notching project would take an estimated six years to complete,
depending on the effects of annual precipitation upon the construction
schedule.
b. Dam Removal Alternative. This alternative would eliminate
seismic safety and flooding risks through the removal of the Dam and
the accumulated sediment behind the Dam. A new access road would be
constructed to connect Carmel Valley Road to the Carmel Valley Filter
Plant, to bypass the Sleepy Hollow community and to improve safety for
large construction equipment. In addition, road access from the filter
plant to the Dam would be improved. The existing primitive road from
the Old Carmel River Dam to the base of San Clemente Dam would be
rebuilt to an elevation above winter flood levels. Both the Carmel
River and San Clemente Creek would be diverted around the reservoir and
Dam site and the reservoir would be dewatered each year during
construction. Accumulated sediment would be removed from behind the Dam
over three seasons by excavation with heavy equipment and transport
from the reservoir by truck or via a conveyor belt system to a disposal
area near the Carmel Valley Filter Plant. The existing Dam and fish
ladder would be demolished and removed from the site. A new intake
structure would be constructed to allow CAW to continue serving the
upper Carmel Valley Village area. The river channel would be restored
through the historic inundation zone. If the Dam and sediment were
removed in stages, a trap and truck facility would need to be built and
operated at the Old Carmel River Dam for at least three years. The Dam
removal project would take an estimated seven years to complete,
depending on the effects of annual precipitation upon the construction
schedule.
c. No Action Alternative. Under this alternative, no changes to the
existing Dam would be made. The Dam would be left in place with all its
existing facilities, although the fish ladder would be replaced with a
new ladder compliant with existing NMFS and CDFG criteria to provide
fish passage. Most of the sediment would be left in place behind the
Dam. The reservoir would continue to accumulate sediment at an average
rate of about 15 acre-feet per year. Minor sediment removal may occur
to maintain the existing water supply intake serving the upper Carmel
Valley Village acre. The existing draw down ports in the Dam and the
existing fish bypass facility would both likely remain operational
until the reservoir fills with sediment. The existing road between the
Carmel Valley Filter Plant and the Dam would be improved to provide
access to the Dam site for fish ladder construction equipment and
supplies.
4. Scoping Process: Pursuant to NEPA, the USACE must include a
scoping process for the Draft EIS/EIR. Scoping preliminarily involves
determining the scope of the issues to be addresses in the Draft EIR/
EIS and identifying the anticipated significant issues for in-depth
analysis. The scoping process includes public participation to
integrate public needs and concerns regarding the proposed action.
a. Public Involvement Program: Venues for public comment on the
proposed action will include: Scoping meetings to be held on November
4, 2004 in Carmel Valley; preparation of a Draft EIR/EIS; and receipt
of public comment in response to the Draft EIR/EIS.
b. Significant Issues to be Analyzed in Depth in the Draft EIR/EIS
include: Impacts to the aquatic environments; impacts to endangered
species, including but not limited to the California red-legged frog
and the California Central Coast steelhead; water quality; cultural
resources; traffic, fish and wildlife resources; public safety,
including downstream flooding; and other issues identified through the
public involvement process and interagency coordination.
c. Environmental Review/Consultation Requirements: NEPA; Section
404 of the Clean Water Act; Section 401 of the Clean Water Act;
Endangered Species Act; Magnusun-Stevens Act Provision--Essential Fish
Habitat; Clean Air Act; National Historic Preservation Act.
d. Scoping Meeting/Availability of Draft EIR/EIS: The USACE will
hold a public scoping meeting to provide information on the project and
receive oral or written comments on the scope of the document. This
scoping meeting for the project will be held at 6:30 p.m. to Thursday,
November 4, 2004, at the Rancho Canada Gold Club, 4860 Carmel Valley
Road, Carmel Valley, California. The Draft EIR/EIS is expected to be
available for public review in winter of 2006.
Dated: September 21, 2004.
Calvin C. Fong,
Regulatory Branch Chief.
[FR Doc. 04-21994 Filed 9-29-04; 8:45 am]
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