[Federal Register Volume 59, Number 41 (Wednesday, March 2, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-4683]
[[Page Unknown]]
[Federal Register: March 2, 1994]
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INTERNATIONAL BOUNDARY AND WATER COMMISSION
United States--Mexico Joint Project for Immediate Emergency
Removal of Sediment in the Lower Colorado River in Mexico, Morelos Dam
to the Northerly International Boundary--Finding of No Significant
Impact
agency: United States Section, International Boundary and Water
Commission, United States and Mexico.
action: Notice of Finding of No Significant Impact.
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summary: Based on a revised draft environmental assessment, the United
States Section of the International Boundary and Water Commission,
United States and Mexico (USIBWC), finds that the proposed action that
the United States Government and the Government of Mexico engage in a
joint project for immediate emergency removal of sediment in the lower
Colorado River in Mexico from Morelos Dam to the Northerly
International Boundary (NIB) is not a major federal action that would
have a significant adverse effect on the quality of the human
environment. Therefore, pursuant to section 102(2)(C) of the National
Environmental Policy Act of 1969; the Council on Environmental Quality
Final Regulations (40 CFR parts 1500 through 1508); and the USIBWC's
Operational Procedures for Implementing Section 102 of NEPA, published
in the Federal Register September 2, 1981 (46 FR 44083-44094); the
USIBWC hereby gives notice that an environmental impact statement will
not be prepared for the proposed project.
addresses: Mr. M.R. Ybarra, United States Section Secretary; United
States Section, International Boundary and Water Commission, United
States and Mexico, 4171 North Mesa Street, C-310, El Paso, Texas 79902.
Telephone: 915/534-6698.
SUPPLEMENTARY INFORMATION:
Proposed Action
The action proposed is for the United States Government and the
Government of Mexico to engage in a joint project to remove sediment in
the lower Colorado River in Mexico from Morelos Dam to the Northerly
International Boundary (NIB).
The need for the project arises from extraordinary winter storm
runoff in 1993 in the Gila River basin which resulted in the filling
and spilling of Painted Rock Dam, located some 116 miles (187
kilometers) upstream of the Gila River's confluence with the Colorado
River. The sustained high flows carried a large sediment load, causing
dangerous accumulations in the international boundary segment of the
Colorado River.
The sediment removal is necessary to provide immediate flood
control relief in the vicinity of Morelos Dam and to enable Mexico to
receive full deliveries of their 1944 Treaty waters. All sediment
removal activities will be conducted in Mexico.
Alternatives Considered
Three alternatives, including the No Action Alternative and the
Proposed Action Alternative, were considered:
The No Action Alternative would result in accumulated sediment not
being removed from the lower Colorado River in the vicinity of Morelos
Dam. Mexico would not be able to divert full domestic and irrigation
allotments. Serious impacts to human health could result from an
absence of an adequate domestic water supply. Sediment accumulation in
the Morelos Dam system would increase flood stage elevations. The
United States would not be acting in furtherance of the 1944 Water
Treaty requirement to recommend and carry out flood control activities
and the 1970 Boundary Treaty requirements for boundary preservation.
The Proposed Action Alternative is a joint United States/Mexico
emergency project to remove sediment upstream of the Morelos Dam flood
control gates for a distance yet to be determined, but no further
upstream than the NIB, and downstream of the Morelos Dam intake gates.
The IBWC, on behalf of the United States and Mexico, would coordinate
the work utilizing, as authorized in the 1944 Water Treaty, the
resources of the U.S. Department of Interior, Bureau of Reclamation
(Reclamation), and the Mexican National Water Commission.
The project includes the removal of an estimated minimum 183,000
cubic yards (140,000 cubic meters) of sediment downstream of the
Morelos Dam intake structure in Mexico, assigned to Mexico, and removal
of an estimated minimum 314,000 cubic yards (240,000 cubic meters) of
sediment, assigned to the United States, immediately upstream of
Morelos Dam in the Colorado River, also in Mexico, up to the NIB. The
Mexican government has requested the United States government perform
the part of the work assigned to Mexico at full reimbursement to the
United States Government because the existing Mexican equipment does
not have the capacity to remove the amount of sediment necessary to
restore the intake canal capacity to 5,650 cubic feet per second (160
cubic meters per second).
Work will be performed utilizing dredging equipment. It may also be
necessary to use earth moving equipment along the Mexican bank of the
Colorado River. The spoil material will be temporarily placed in Mexico
just upstream of Morelos Dam. Mexico will remove the spoil material to
a permanent disposal site in Mexico in the near future. The United
States will advise Mexico on disposal site preparation in that country.
The sediment has been tested for the presence of pesticides and heavy
metals. The result of the tests will be furnished to the interested
resource agencies when they become available.
This alternative will improve the flood carrying capacity in the
Colorado River to pass flood flows through the NIB similar to those
experienced during the 1993 Gila River floods. The Morelos Dam system
will also allow Mexico to fully divert the waters delivered by the
United States under the 1944 Water Treaty along with small flood flows
that may arrive at the NIB. The United States would be acting in
furtherance of the 1944 Water Treaty requirement to recommend and carry
out flood control activities and the 1970 Boundary Treaty requirements
for boundary preservation.
The Sediment Removal and Flood Control Alternative would result in
the United States and Mexico concluding an international agreement
through a Minute of the IBWC for sediment removal in the Colorado River
from the confluence of the Gila River to the lower end of the Mexicali
Valley Irrigation District, including the Morelos Dam intake canal.
This action would restore the carrying capacity of the river channel to
about 25,000 cubic feet per second (708 cubic meters per second) to
permit passage of the 100-year flood discharge of approximately 40,000
cubic feet per second (1,130 cubic meters per second) with overbank
discharges that will not overtop or endanger flood control levees in
either the United States or in Mexico. This activity would also improve
the Colorado River channel gradient in the lower end of the Mexicali
Valley Irrigation District to increase the velocity of flood flows into
the Laguna Salada diversion channel and to the Gulf of California. This
alternative would also allow the United States and Mexico to resolve
existing boundary issues and other differences in a cooperative manner.
This alternative would be a major federal undertaking which could
not be accomplished within the short time needed to correct water
diversion problems or handle potential significant flood events during
1994. An undertaking of this magnitude would also involve a
consideration of river stabilization and river rectifications in
addition to sediment removal. Such activities would require extensive
cost-benefit analysis and environmental impact evaluation. This
alternative was therefore not given further consideration. Instead, the
elements of this alternative were considered as elements that merit
considerable binational study for a possible longer term activity.
Revised Draft Environmental Assessment
The USIBWC met with the interested resource agencies on February
15, 1994, in Yuma, Arizona, to discuss the proposed action. The Revised
Draft Environmental Assessment (RDEA) for the proposed project was
completed on February 16, 1994, and made available for review and
comment.
On the basis of the consensus reached with the interested resource
agencies and the RDEA, the USIBWC has determined that an environmental
impact statement is not required for the United States Government and
the Government of Mexico to engage in a joint project for immediate
emergency removal of sediment in Mexico from Morelos Dam to the NIB and
hereby provides notice of a finding of no significant impact.
An environmental impact statement will not be prepared unless
additional information which may affect this decision is brought to our
attention within thirty (30) days of the date of this Notice.
The RDEA and Draft Finding of No Significant Impact (FONSI) have
been forwarded to the Environmental Protection Agency and various
Federal, State, and local agencies and interested parties. A limited
number of copies of these documents are available to fill single copy
requests at the above address.
Dated: February 23, 1994.
Manuel R. Ybarra,
Secretary.
[FR Doc. 94-4683 Filed 3-1-94; 8:45 am]
BILLING CODE 4710-03-M
