[Federal Register: June 29, 2007 (Volume 72, Number 125)]
[Notices]
[Page 35721-35722]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29jn07-75]
[[Page 35721]]
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INTERNATIONAL BOUNDARY AND WATER COMMISSION, UNITED STATES AND MEXICO
United States Section; Notice of Availability of a Draft
Environmental Assessment and Finding of No Significant Impact for
Improvements to the Donna-Brownsville Levee System, in the Lower Rio
Grande Flood Control Project, Hidalgo and Cameron Counties, Texas
AGENCY: United States Section, International Boundary and Water
Commission, United States and Mexico.
ACTION: Notice of Availability of Draft Environmental Assessment (EA)
and Draft Finding of No Significant Impact (FONSI).
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SUMMARY: Pursuant to Section 102(2)(c) of the National Environmental
Policy Act (NEPA) of 1969, the Council on Environmental Quality Final
Regulations (40 CFR Parts 1500 through 1508), and the United States
Section, International Boundary and Water Commission's (USIBWC)
Operational Procedures for Implementing Section 102 of NEPA, published
in the Federal Register September 2, 1981, (46 FR 44083); the USIBWC
hereby gives notice that the Draft Environmental Assessment and FONSI
for Improvements to the Donna-Brownsville Levee System, in the Lower
Rio Grande Flood Control Project, located in Hidalgo and Cameron
Counties, Texas, are available. An environmental impact statement will
not be prepared unless additional information which may affect this
decision is brought to our attention within 30-days from the date of
this Notice.
FOR FURTHER INFORMATION CONTACT: Daniel Borunda, Environmental
Protection Specialist, Environmental Management Division, United States
Section, International Boundary and Water Commission; 4171 N. Mesa, C-
100; El Paso, Texas 79902. Telephone: (915) 832-4767; e-mail:
daniel.borunda@ibwc.state.gov.
DATES: Comments on the Draft EA and Draft FONSI will be accepted within
30 days from the date of this Notice.
SUPPLEMENTARY INFORMATION:
Background
The USIBWC is authorized to construct, operate, and maintain any
project or works projected by the United States of America on the Lower
Rio Grande Flood Control Project (LRGFCP), as authorized by the Act of
the 74th Congress, Sess. I Ch. 561 (H.R. 6453), approved August 19,
1935 (49 Stat. 660), and codified at 22 U.S.C. Section 277, 277a, 277b,
277c, and Acts amendatory thereof and supplementary thereto.
The LRGFCP was constructed to protect urban, suburban, and highly
developed irrigated farmland along the Rio Grande delta in the United
States and Mexico.
The USIBWC, in cooperation with the U.S. Fish and Wildlife Service
(USFWS), prepared this Draft Environmental Assessment (Draft EA) for
the proposed action of raising the Donna-Brownsville Levee System
located in Hidalgo and Cameron Counties, Texas to improve flood
control. This levee system is part of the LRGFCP that extends
approximately 180 miles from the Town of Pe[ntilde]itas in south Texas
to the Gulf of Mexico. The Donna-Brownsville Levee extends 65 miles
along the Rio Grande, downstream from the Donna Pump Station in Hidalgo
County to an area east of Brownsville, approximately 28 miles upstream
of the Gulf of Mexico, in Cameron County.
Proposed Action
The Proposed Action would increase the flood containment capacity
of the Donna-Brownsville Levee System by raising elevation of a number
of levee segments to meet a 3-foot freeboard design criterion for flood
protection. Height increases up to 2 feet are typically needed to reach
the design freeboard value. The increase in levee height will result in
an expansion to the levee footprint by lateral extension of the
structure. Structural improvements may be required for some levee
segments where seepage is a potential problem.
Alternatives to the Proposed Action
A No Action Alternative was evaluated for the Donna-Brownsville
Levee System. This alternative will retain the existing configuration
of the system, as designed over 30 years ago, and the current level of
protection currently associated with this system. Under severe storm
events, current containment capacity may be insufficient to fully
control Rio Grande flooding, with risks to personal safety and
potential property damage.
Summary of Findings
Pursuant to NEPA guidance (40 Code of Federal Regulations 1500-
1508), The President's Council on Environmental Quality issued
regulations for NEPA implementation, which included provisions for both
the content and procedural aspects of the required Environmental
Assessment. The USIBWC completed an EA of the potential environmental
consequences of raising the Donna-Brownsville Levee System to meet
current requirements for flood control. The EA, which supports this
Finding of No Significant Impact, evaluated the Proposed Action and No
Action Alternative.
Levee System Evaluation
No Action Alternative
The No Action Alternative was evaluated as the single alternative
action to the Proposed Action. The No Action Alternative will retain
the current configuration of the Donna-Brownsville Levee System, with
no impacts to biological and cultural resources, land use, community
resources, or environmental health issues. In terms of flood
protection, however, current containment capacity under the No Action
Alternative may be insufficient to fully control Rio Grande flooding
under severe storm events, with associated risks to personal safety and
property.
Proposed Action
Biological Resources
Improvements to the Donna-Brownsville Levee System require
excavation and fill activities that would affect plant communities
within the expanded levee footprint area. Nearly all vegetation
removal, 51.5 acres, would be limited to invasive-species grassland
that is expected to be rapidly re-established. While approximately 17
percent of the 65 mile levee system is adjacent to conservation areas,
those non-native grasslands are located within the right-of-way (ROW)
and have very limited value as wildlife habitat. No significant effects
are anticipated for any of the 15 threatened and endangered species
with potential habitat in the vicinity of the levee system. No wetlands
are located within the potential levee expansion area.
Cultural Resources
Improvements to the Donna-Brownsville Levee System may adversely
affect known archaeological resources, by mechanical excavation or by
burial under the expanded levee footprint. Resources potentially
affected include eight areas that may contain historic or prehistoric
archaeological materials, and one known archaeological site. Out of 65
historic-age resources located in the levee system vicinity, twelve
could be affected by the proposed levee improvements. Those historic-
age resources are mostly associated with irrigation structures and
canals adjacent to the levee system.
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Water Resources
Improvements to the levee system would increase flood containment
capacity to control the design flood event with a negligible increase
in water surface elevation. Levee footprint expansion would not affect
water bodies.
Land Use
The expansion would take place almost completely within the ROW and
would not affect urban or agricultural lands. A minimum removal of
woodland from natural resources management areas, less than 1 acre,
would be required.
Community Resources
In terms of socioeconomic resources, the influx of federal funds
into Hidalgo and Cameron Counties from the levee improvement project
would have a positive local economic impact limited to the construction
period; the impact would represent less than 1 percent of the annual
county employment, income and sales values. No adverse impacts to
disproportionately high minority and low-income populations were
identified for construction activities. Moderate utilization of public
roads is required during construction; a temporary increase in access
road use would be required for equipment mobilization to staging areas.
Environmental Health Issues
Estimated air emissions of five criteria pollutants during
construction represent from 0.06 percent to 1.64 percent of the Hidalgo
and Cameron Counties annual emissions inventory. There would be a
moderate increase in ambient noise levels due to excavation and fill
activities. No long-term and regular exposure is expected above noise
threshold values. A database search identified a number of waste
storage or disposal sites in the levee system vicinity, all located
within the City of Brownville. None of those sites would affect, or be
affected, by the levee improvement project.
Best Management Practices and Mitigation
Engineering design measures will be used, including optimization of
the levee expansion alignment to avoid impacts on wooded vegetation,
wetlands, and other natural resources. Best management practices during
construction will include development of a storm water pollution
prevention plan to avoid impacts to receiving waters, and use of
sediment barriers and soil wetting to minimize erosion.
To protect vegetation, the construction corridor may be re-
vegetated with herbaceous or woody vegetation, as agreed with the
natural resources management organization where the levee expansion
corridor is located. To protect wildlife, construction activities will
be scheduled to occur, to the extent possible, outside the March to
August bird migratory season.
To avoid significant impacts on cultural resources, an additional
survey of archaeological and historical resources will be conducted
following completion of the engineering design phase, and mitigation
actions will be adopted as recommended by the Texas Historical
Commission (THC). Measures to avoid or minimize potential impacts to
historical or archaeological resources will be specified in a
Memorandum of Agreement between THC and the USIBWC.
Availability
Single hard copies of the Draft Environmental Assessment and
Finding of No Significant Impact may be obtained by request at the
above address. Electronic copies may also be obtained from the USIBWC
Home Page at http://www.ibwc.state.gov.
Dated: June 25, 2007.
Susan Daniel,
General Counsel.
[FR Doc. E7-12509 Filed 6-28-07; 8:45 am]
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