[Federal Register Volume 59, Number 145 (Friday, July 29, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-18455]


[[Page Unknown]]

[Federal Register: July 29, 1994]


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INTERNATIONAL BOUNDARY AND WATER COMMISSION, UNITED STATES AND MEXICO

 

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 availability of final Environmental Assessment and 
Finding of No Significant Impact.

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SUMMARY: 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 U.S. Section's 
Operational Procedures for Implementing Section 102 of NEPA, published 
in the Federal Register September 2, 1981 (46FR44083-44094); the U.S. 
Section hereby gives notice that the Final Environmental Assessment and 
Final Finding of No Significant Impact for the proposed action of the 
United States Government and the Government of Mexico engaging 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 available. A Notice of Finding of No 
Significant Impact dated February 23, 1994, provided a thirty day 
review and comment period before making the Finding final. The Notice 
was published in the Federal Register March 2, 1994 (59 FR 9994-9995).
    Regarding the applicability of NEPA to the proposed project, the 
U.S. Section is an integral part of the International Boundary and 
Water Commission (IBWC), an international organization designated under 
the International Organizations Immunity Act, 22 U.S.C. 288. The 
proposed project is a Commission action in Mexico. The U.S. Section, as 
a matter of policy discretion, has carried out the environmental review 
for the proposed emergency project. The U.S. Section considers the 
Environmental Assessment to be adequate under the U.S. Section's final 
procedures for implementing NEPA as published in the Federal Register 
September 2, 1981 (46 FR 44083). Pursuant to these procedures, the U.S. 
Section consulted with the Department of State and has been advised 
that NEPA is not applicable to this project.

FOR FURTHER INFORMATION CONTACT:
Dr. Conrad G. Keyes, Jr., Principal Engineer, Planning, United States 
Section, International Boundary and Water Commission, United States and 
Mexico, 4171 North Mesa Street, C-310, El Paso, Texas 79902. Telephone: 
915/534-6703.

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:
    1. No Action Alternative--This 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.
    2. Proposed Action Alternative--This alternative is a joint United 
States/Mexico emergency project to remove sediment upstream of the 
Morelos Dam flood control gates to the NIB, and downstream of the 
Morelos Dam intake gates in the Mexican intake canal. 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 the Mexican intake canal and removal of 
an estimated minimum 314,000 cubic yards (240,000 cubic meters) of 
sediment immediately upstream of Morelos Dam in the Colorado River, 
also in Mexico, up to the NIB. 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 was tested for 
the presence of pesticides and heavy metals. The results do not show 
the presence of pesticides and the metals compare favorably with 
Arizona background data and the element baseline for western U.S. 
soils. The results of the tests are included in the Final Environmental 
Assessment.
    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.
    3. Sediment Removal and Flood Control Alternative--This 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.

Availability

    Single copies of the Final Environmental Assessment and Final 
Finding of No Significant Impact may be obtained at the above address.

    Dated: July 22, 1994.
Suzette Zaboroski,
Staff Counsel.
[FR Doc. 94-18455 Filed 7-28-94; 8:45 am]
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