United States Section; Notice of Availability of a Final Environmental Assessment and Final Finding of No Significant Impact for Flood Control Improvements to the Arroyo Colorado Floodway, Hidalgo and Cameron Counties, TX, 28952-28954 [E9-14314]

Download as PDF 28952 Federal Register / Vol. 74, No. 116 / Thursday, June 18, 2009 / Notices southern Beaufort Sea: An Agreement between the Inuvialuit Game Council and the North Slope Borough Fish and Game Committee. In Transactions of North American Wildlife and Natural Resources Conference 56:337–343. Ovsyanikov, N.G. 2006. Research and conservation of polar bears on Wrangel Island. Pp. 167–171, In J. Aars, N.J. Lunn, and A.E. Derocher (eds.), Proceeding of the 14th Working Meeting of the IUCN/SSC Polar Bear Specialist Group, 20–24 June 2005, Seattle, Washington, U.S.A. IUCN, Gland, Switzerland, and Cambridge, U.K. Overland, J.E., and M. Wang. 2007. Future regional Arctic sea ice declines. Geophysical Research Letters 34: L17705. Paetkau, D., S.C. Amstrup, E.W. Born, W. Calvert, A.E. Derocher, G.W. Garner, F. Messier, I. Stirling, M.K. Taylor, O. Wiig, and C. Strobeck. 1999. Genetic Structure of the world’s polar bear populations. Molecular Ecology 8:1571–1584. Parkinson, C.L., D.J. Cavalieri, P. Gloersen, H.J. Zwally, and J.C. Comiso. 1999. Arctic sea ice extents, areas, and trends, 1978–1996. Journal of Geophysical Research 104(C9):20837–20856. Ray, C.E. 1971. Polar bear and mammoth on the Pribilof Islands. Arctic 24:9–19. Regehr, E.V., S.C. Amstrup, and I. Stirling. 2006. Polar bear population status in the Southern Beaufort Sea. Report Series 2006– 1337, U.S. Department of the Interior, U.S. Geological Survey, Anchorage, Alaska. 55 pp. Regehr, E.V., C.M. Hunter, H. Caswell, S.C. Amstrup, and I. Stirling. 2007. Polar bears in the Southern Beaufort Sea I: Survival and breeding in relation to sea ice conditions, 2001–2006. U.S. Geological Survey, Alaska Science Center, Administrative Report. 45 pp. Rode, K.D., S.C. Amstrup, and E.V. Regehr. 2007. Polar Bears in the southern Beaufort Sea III: stature, mass, and cub recruitment in relationship to time and sea ice extent between 1982 and 2006. U.S. Dept. of the Interior, U.S. Geological Survey Administrative Report, Reston, Virginia. 28 pp. Rothrock, D.A., Y. Yu, and G.A. Maykut. 1999. Thinning of the Arctic sea-ice cover, Geophysical Research Letters 26:3469–3472. Rush, S.A., K. Borga, R. Dietz, E.W. Born, C. Sonne, T. Evans, D.C.G. Muir, R.L. Letcher, R.J. Norstrom, and A.T. Fisk. 2008. Geographic Distribution of selected elements in the livers of polar bears from Greenland, Canada, and the United States. Environmental Pollution 153 (3): 618–626. Schliebe, S.L., S.C. Amstrup, and G.W. Garner. 1995. The status of polar bear in Alaska, 1993. Pp. 125–139, In O. Wiig, G.W. Garner (eds.), Proceedings of the Eleventh Working Meeting of the IUCN/SSC Polar Bear Specialist Group, Copenhagen, Denmark. IUCN, Gland, Switzerland, and Cambridge, UK. v + 192 pp. Schliebe, S., T.J. Evans, S. Miller, C. Perham, J. Wilder, and L.J. Lierheimer. 2006. Polar bear management in Alaska 2000–2004. Pp. 63–76, In J. Aars, N.J. Lunn, and A.E. Derocher (eds.), Proceeding of the 14th Working Meeting of the IUCN/SSC Polar Bear Specialist Group, 20–24 June 2005, Seattle, Washington, U.S.A. IUCN, Gland, Switzerland, and Cambridge, U.K. VerDate Nov<24>2008 21:58 Jun 17, 2009 Jkt 217001 Scribner, K.T., G.W. Garner, S.C. Amstrup, and M.A. Cronin. 1997. Population genetic studies of the polar bear (Ursus maritimus): a summary of available data and interpretation of results. Pp. 185–196, In Dizon, S., J. Chivers, and W. Perrin (eds.), Molecular genetics of marine mammals, incorporating the proceedings of a workshop on the analysis of genetic data to address problems of stock identity as related to management of marine mammals. Spec. Pub. #3 of the Society of Marine Mammalogy. Serreze, M.C., M.M. Holland, and J. Stroeve. 2007. Perspectives on the Arctic’s shrinking sea-ice cover. Science 315: 1533– 1536. Smithwick, M., J.W. Martin, S.A. Mabury, K. Solomon, C. Sonne, E.W. Born, R. Dietz, A.E. Derocher, R.L. Letcher, T.J. Evans, G.W. Gabrielsonm, J. Nagy, I. Stirling, and D.C.G. Muir. 2005. A circumpolar study of perfluoroalkyl contaminants in polar bears (Ursus maritimus). Environmental Science and Technology 39(15):5517–5523. Smithwick, M.J., R.J. Norstrom, S.A. Maybury, K. Solomon, T.J. Evans, I. Stirling, M.K. Taylor, and D.C.G. Muir. 2006. Temporal trends of perfluoroalkyl contaminants in polar bears (Ursus maritimus) from two locations in the North American Arctic, 1972–2002. Environmental Science and Technology. 40(4):1139–1143. Stishov, M.S. 1991a. Results of aerial counts of the polar bear dens on the arctic coast of the extreme Northern Asia. Pp. 90– 92, In Amstrup, S.C., and Wiig, ;. (eds.), Polar Bears: Proceedings of the Tenth Working Meeting of the IUCN/SSC Polar Bear Specialist Group. IUCN, Gland, Switzerland, and Cambridge, U.K. Stishov, M.S. 1991b. Distribution and number of polar bear maternity dens on Wrangel and Herald islands, in 1985–1989, pp. 91–115 in Amerirkhavov, A.M. (ed.), Population and Communities of Mammals on Wrangel Island. Moscow, CNIL Glavokhhoty RSFSR. (in Russian). Stishov, M.S., G.W. Garner, S.M. Arthur, and V.G.B. Barnes Jr. 1991. Distribution and relative abundance of maternal polar bear dens in the Chukotka Peninsula region, U.S.S.R. p. 67 in Abstracts, Ninth Biennial Conference on the Biology of the Marine Mammals, 5–9 December 1991, Chicago, Illinois, U.S.A. Stroeve, J., M. Serreze, S. Drobot, S. Gearheard, M. Holland, J. Maslanik, W. Meier, and T. Scambos. 2008. Arctic Sea Ice Extent Plummets in 2007. EOS, Transactions, American Geophysical Union 89(2):13–14. Treseder, L., and A. Carpenter. 1989. Polar bear management in the Southern Beaufort Sea. Info. N. 15(4):2–4. USFWS. Unpublished data (polar bear harvest information). Available from: USFWS Marine Mammals Office, 1011 East Tudor Road, Anchorage, AK 99503. Uspenski, S.M. 1986. Research and management of polar bear populations in the USSR, 1981–85. Pages 133–136 in Proceedings of the Ninth Working Meeting of the IUCN/SSC Polar Bear Specialist Group, IUCN, Gland, Switzerland, and Cambridge, U.K. Verrault, J., D.C.G. Muir, R.J. Norstrom, I. Stirling, A.T. Fisk, G.W. Gabrielsen, A.E. PO 00000 Frm 00074 Fmt 4703 Sfmt 4703 Derocher, T.J. Evans, R. Dietz, C. Sonne, G.M. Sandala, W. Gebbink, F.F. Riget, E.W. Born, M.K. Taylor, J. Nagy, and R.J. Letcher. 2005. Chlorinated hydrocarbon contaminants and metabolites in polar bears (Ursus maritimus) from Alaska, Canada, East Greenland, and Svalbard: 1996–2002. The Science of the Total Environment 351–352:369–390. Wade, P.R., and R. Angliss. 1997. Guidelines for assessing marine mammal stocks: Report in the GAMMS Workshop, April 3–5, 1996, Seattle, WA. 93 pp. Wilson, D.E. 1976. Cranial variation in polar bears. International Conference Bear Research and Management 3:447–453. Woshner, V.M., T.M. O’Hara, G.R. Bratton, and V.R. Beasley. 2001. Concentrations and interactions of selected essential and nonessential elements in ringed seals and polar bears of Arctic Alaska. Journal of Wildlife Diseases. (37):711–721. Zdor, Eduard. Personal Communication. Executive Director, Association of Traditional Marine Mammal Hunters of Chukotka. Authority: The authority for this action is the Marine Mammal Protection Act of 1972, as amended (16 U.S.C. 1361 et al.). Dated: June 9, 2009. Marvin Moriarty, Acting Director, Fish and Wildlife Service. [FR Doc. E9–14346 Filed 6–17–09; 8:45 am] BILLING CODE 4310–55–P INTERNATIONAL BOUNDARY AND WATER COMMISSION United States Section; Notice of Availability of a Final Environmental Assessment and Final Finding of No Significant Impact for Flood Control Improvements to the Arroyo Colorado Floodway, Hidalgo and Cameron Counties, TX AGENCY: United States Section, International Boundary and Water Commission, United States and Mexico. ACTION: Notice of Availability of Final Environmental Assessment (EA) and Final Finding of No Significant Impact (FONSI). SUMMARY: Pursuant to Section 102(2)(c) of the National Environmental Policy Act (NEPA) of 1969 (42 U.S.C. 4321 et seq.), 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 of availability of the Final Environmental Assessment and FONSI for Flood Control Improvements to the Arroyo Colorado Floodway, a component of the E:\FR\FM\18JNN1.SGM 18JNN1 Federal Register / Vol. 74, No. 116 / Thursday, June 18, 2009 / Notices interior floodways system of the Lower Rio Grande Flood Control Project. FOR FURTHER INFORMATION CONTACT: Rita Crites, 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) 832–4781; e-mail: ritacrites@ibwc.gov. DATES: The Final EA and FONSI will be available June 11, 2009. SUPPLEMENTARY INFORMATION: Background The Arroyo Colorado is an ancient distributary of the Rio Grande, and it serves as drainage for crop irrigation, municipal wastewater returns, and as a floodway during periods of heavy precipitation in the Lower Rio Grande Valley. The project area includes two segments of the flood control levee system with a combined length of 11 miles. The USIBWC prepared this EA for the proposed action to increase flood control of the Arroyo Colorado Levee System by raising the elevation of these two levee segments for improved flood protection. The beginning of this project is a 2.1 mile Divisor Dike near the juncture point of the Arroyo Colorado and the North Floodway in Hidalgo County, extending a total of 6.9 miles to the Willacy Canal. The remaining segment is 4.0 miles from the Willacy Canal ending at White Ranch Road in Cameron County, Texas. Proposed Action The proposed levee rehabilitation improvements consist of: (1) Raising the top-of-levee elevation, (2) conducting geotechnical investigations and testing to determine the type and extent of any required remediation improvements due to slope stability, seepage, levee settlement, and any other geotechnical issues that may cause levee failure; and (3) modifying, if necessary, hardware or structures located along the levee reaches. Any modifications will be in compliance with the Texas Historical Commission recommendations. The top elevation of the levee-raising improvements will be to provide containment of flood flows with a minimum freeboard of 3 feet for water surface elevations as calculated in the USIBWC 2003 Hydraulic Model for the LRGFCP. A centered levee expansion is assumed for most areas of the Arroyo Colorado Levee system, except south of La Feria reservoir, where levee expansion will be offset to the riverside of the existing levee. VerDate Nov<24>2008 21:58 Jun 17, 2009 Jkt 217001 The proposed action will increase the height of the levee up to 2 feet for approximately 8.6 percent of the 11mile segment. Approximately 4 percent of the levee segment will be increased from 2 to 4 feet, and approximately 2.4 percent will be increased from 4 to 6 feet. The existing levee is a raised trapezoidal compacted-earth structure with a crown width of 16 feet, a typical height ranging from 10 to 15 feet, and approximately 3:1 side slope ratio (horizontal run: vertical rise). For a typical levee cross-section at the ACF that requires additional fill material to the crown the levee footprint would be expanded at a 1:6 ratio (crown height: footprint length). The footprint expansion would be equally divided between the riverside and landside (centered expansion) or entirely on one side (offset expansion). Moderately higher increases will be needed in a small segment that accounts for less than 1.2 percent of the total length. In areas where existing topography is too steep to allow levee expansion, construction solutions, including armored banks (riprap) or retaining walls, will be used. Excavation outside the existing right-of-way is not anticipated. The EA assesses potential environmental impacts of the proposed action and the no action alternative. Potential impacts on natural, cultural, and other resources were evaluated, and mitigation measures were incorporated into the proposed action. A Finding of No Significant Impact was issued for the proposed action based on a review of the facts and analyses contained in the EA. 28953 alternative will retain the current configuration of the ACF levee system, with no impacts to biological and cultural resources, water resources, land use, soil, 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, including associated risks to personal safety and property. The levee system will not meet FEMA requirements for levee system certification. Proposed Action Biological Resources Levee System Evaluation Biological resources in the vicinity of the levee systems are dominated by agricultural fields, rangelands, and nonnative grasslands. There are some woody species along the margins of the Arroyo Colorado, drainage ditches from irrigation fields, and adjacent to borrow pits. The 160-foot wide biological survey corridor, centered on the existing levee, includes approximately 221 acres, primarily composed of non-native grasslands dominated by buffelgrass and king ranch bluestem. The proposed action will raise the levee using a centered expansion, except in areas south of La Feria reservoir, where an offset expansion will be utilized. The proposed levee expansion will remove non-native grasslands on the levee slopes and adjacent areas. Native grasses will be planted immediately after the completion of the project, and the levee expansion will not occur in wooded areas. Less than one-half acre of nonjurisdictional wetlands will be affected, but no jurisdictional wetlands will be affected by the levee expansion. No habitats used by federally or state-listed threatened or endangered species will be impacted by the levee expansion. In areas adjacent to sensitive areas such as water bodies, levee expansion may be altered to an offset expansion toward the riverside of the levee to avoid impacting sensitive resources. In areas where the existing topography is too steep to allow levee expansion, construction solutions, including armored banks, will prevent erosion of the levee slopes. The construction solutions will not affect sensitive habitats, including wooded areas, habitats for threatened and endangered species, or jurisdictional wetlands. No Action Alternative Cultural Resources The no action alternative was evaluated as the single alternative action to the proposed action. The no action Improvements to the ACF levee system may adversely affect prehistoric and historic archaeological resources. Summary of Findings Pursuant to the National Environmental Policy Act (NEPA) guidance (40 CFR 1500–1508), The President’s Council on Environmental Quality issued regulations for implementing NEPA, which included provisions for both the content and procedural aspects of the required EA. The USIBWC completed an EA of the potential environmental consequences of raising the Arroyo Colorado Floodway (ACF) 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. PO 00000 Frm 00075 Fmt 4703 Sfmt 4703 E:\FR\FM\18JNN1.SGM 18JNN1 28954 Federal Register / Vol. 74, No. 116 / Thursday, June 18, 2009 / Notices Some areas adjacent to the toe of the levee contain intact archaeological resources. Adverse effects to archaeological resources may occur from the use of heavy equipment during levee construction that could disturb surface or shallowly buried deposits. Adverse effects may also occur to archaeological deposits that will be buried by the addition of the fill material on the surface above them. Alternatively, levee footprint expansion may protect archaeological resources by capping with fill material, preserving those resources in place. Architectural resources may be adversely affected by levee height increases or by expansion of the levee footprint. Potential effects include vibration and ground disturbance from the use of heavy equipment during construction. Design for levee improvements is primarily considering avoidance of the structures as much as possible. However, if structures have to be removed or modified, USIBWC will consult with the Texas Historical Commission (THC) to determine the appropriate level of documentation prior to any modification. In addition to documentation, mitigation of impacts to cultural resources may include their replacement with ‘‘in-kind’’ structures that will look and operate the same. Native American resources may be affected by the levee improvements; consultation with the Native American tribes is ongoing to identify resources or concerns regarding the project. Under NEPA, there will be no significant impacts (i.e., ‘‘unresolvable’’ adverse effects under National Historic Preservation Act [NHPA]) to cultural resources because all cultural resources will be identified and evaluated for National Register of Historic Places (NRHP) eligibility. Any impacts to National Register of Historic Placeseligible resources will be mitigated prior to implementation of levee height increases or footprint expansion, in consultation with the Texas Historical Commission and Native American Tribes. Water Resources Flood control improvements to the ACF will increase flood containment capacity to control the design flood event with a negligible increase in water surface elevation. Levee footprint expansion will not affect water bodies. Land Use Footprint levee expansion, where required, will take place completely within the existing ROW. No urban or agricultural lands will be affected. VerDate Nov<24>2008 21:58 Jun 17, 2009 Jkt 217001 Soil Improvement activity contributing to soil disturbance will include geotechnical investigations and adding soil to the top and sides of the levee. Levee fill material will come from local commercial sources and not from borrow areas in the floodplain. The disturbance of soil will occur within areas where soil has been disturbed and modified by prior levee construction and maintenance activities. Therefore, alteration of soil previously unassociated with the existing levee will not occur. Community Resources In terms of socioeconomic resources, the influx of federal funds into Hidalgo and Cameron Counties from the flood control improvement area will have a positive but minor local economic impact. The impact will be limited to the construction period, and 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 will be required during construction; a temporary increase in access road use will be required for equipment mobilization to staging areas. Environmental Health Issues Estimated air emissions of five criteria pollutants during construction will be discontinuous and represent less than 0.13 percent of the annual emissions inventory within the air quality control region of Hidalgo, Cameron, and Willacy Counties. There will be a moderate increase in ambient noise levels due to construction activities. No long-term and regular exposure is expected above noise threshold values. A database search indicated that no waste storage and disposal sites were within the proposed ACF levee improvement area, and none will affect, or be affected by, the levee improvement project. Best Management Practices When warranted due to engineering considerations, or for protection of biological or cultural resources, the need for levee footprint expansion will be eliminated by levee slope adjustment or use of retaining walls or armored banks. 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. PO 00000 Frm 00076 Fmt 4703 Sfmt 4703 To protect vegetation cover, the embankment improvement areas will be re-vegetated with native herbaceous species. To protect wildlife, construction activities will be scheduled to occur, to the extent possible, outside the March to August bird migratory season. Availability Single hard copies of the Final Environmental Assessment and Finding of No Significant Impact may be obtained by request at the above contact information. Electronic copies may also be obtained from the USIBWC Home Page at http://www.ibwc.gov/ Organization/Environmental/ reports_studies.html. Dated: June 12, 2009. Robert McCarthy, General Counsel. [FR Doc. E9–14314 Filed 6–17–09; 8:45 am] BILLING CODE 7010–01–P DEPARTMENT OF JUSTICE Notice of Lodging of Consent Decree Under the Comprehensive Environmental Response, Compensation, and Liability Act Notice is hereby given that on June 3, 2009, a proposed Consent Decree in United States v. General Electric Co., Civil Action No. 1:09–cv–00545, was lodged with the United States District Court for the District of New Mexico. The Consent Decree resolves the United States’ claims against General Electric Company (‘‘GE’’) at the South Valley Superfund Site located in Albuquerque, New Mexico. Those claims were brought under Section 107 of the Comprehensive Environmental Response, Compensation and Liability Act, 42 U.S.C. 107. The Site consists of several industrial facilities, including an aircraft manufacturing plant currently owned and/or operated by GE and formerly owned and/or operated by the United States Air Force (‘‘USAF’’), the United States Department of Energy (‘‘DOE’’), and others. The Consent Decree requires that GE pay a lump sum of $257,670.00 to reimburse the United States for past response costs, a lump sum of $71,715 toward the United States’ future response costs, and interest accrued on these two sums during the period from November 1, 2002 to the date of entry of the Consent Decree. The Consent Decree also memorializes the obligation of the USAF and DOE to pay a lump sum of $2,605,330.00 in reimbursement for past response costs and a lump sum E:\FR\FM\18JNN1.SGM 18JNN1

Agencies

[Federal Register Volume 74, Number 116 (Thursday, June 18, 2009)]
[Notices]
[Pages 28952-28954]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-14314]


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INTERNATIONAL BOUNDARY AND WATER COMMISSION


United States Section; Notice of Availability of a Final 
Environmental Assessment and Final Finding of No Significant Impact for 
Flood Control Improvements to the Arroyo Colorado Floodway, Hidalgo and 
Cameron Counties, TX

AGENCY: United States Section, International Boundary and Water 
Commission, United States and Mexico.

ACTION: Notice of Availability of Final Environmental Assessment (EA) 
and Final Finding of No Significant Impact (FONSI).

-----------------------------------------------------------------------

SUMMARY: Pursuant to Section 102(2)(c) of the National Environmental 
Policy Act (NEPA) of 1969 (42 U.S.C. 4321 et seq.), 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 of availability of the Final 
Environmental Assessment and FONSI for Flood Control Improvements to 
the Arroyo Colorado Floodway, a component of the

[[Page 28953]]

interior floodways system of the Lower Rio Grande Flood Control 
Project.

FOR FURTHER INFORMATION CONTACT: Rita Crites, 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) 832-4781; e-mail: 
ritacrites@ibwc.gov.

DATES: The Final EA and FONSI will be available June 11, 2009.

SUPPLEMENTARY INFORMATION:

Background

    The Arroyo Colorado is an ancient distributary of the Rio Grande, 
and it serves as drainage for crop irrigation, municipal wastewater 
returns, and as a floodway during periods of heavy precipitation in the 
Lower Rio Grande Valley. The project area includes two segments of the 
flood control levee system with a combined length of 11 miles.
    The USIBWC prepared this EA for the proposed action to increase 
flood control of the Arroyo Colorado Levee System by raising the 
elevation of these two levee segments for improved flood protection.
    The beginning of this project is a 2.1 mile Divisor Dike near the 
juncture point of the Arroyo Colorado and the North Floodway in Hidalgo 
County, extending a total of 6.9 miles to the Willacy Canal. The 
remaining segment is 4.0 miles from the Willacy Canal ending at White 
Ranch Road in Cameron County, Texas.

Proposed Action

    The proposed levee rehabilitation improvements consist of: (1) 
Raising the top-of-levee elevation, (2) conducting geotechnical 
investigations and testing to determine the type and extent of any 
required remediation improvements due to slope stability, seepage, 
levee settlement, and any other geotechnical issues that may cause 
levee failure; and (3) modifying, if necessary, hardware or structures 
located along the levee reaches. Any modifications will be in 
compliance with the Texas Historical Commission recommendations. The 
top elevation of the levee-raising improvements will be to provide 
containment of flood flows with a minimum freeboard of 3 feet for water 
surface elevations as calculated in the USIBWC 2003 Hydraulic Model for 
the LRGFCP. A centered levee expansion is assumed for most areas of the 
Arroyo Colorado Levee system, except south of La Feria reservoir, where 
levee expansion will be offset to the riverside of the existing levee.
    The proposed action will increase the height of the levee up to 2 
feet for approximately 8.6 percent of the 11-mile segment. 
Approximately 4 percent of the levee segment will be increased from 2 
to 4 feet, and approximately 2.4 percent will be increased from 4 to 6 
feet. The existing levee is a raised trapezoidal compacted-earth 
structure with a crown width of 16 feet, a typical height ranging from 
10 to 15 feet, and approximately 3:1 side slope ratio (horizontal run: 
vertical rise). For a typical levee cross-section at the ACF that 
requires additional fill material to the crown the levee footprint 
would be expanded at a 1:6 ratio (crown height: footprint length). The 
footprint expansion would be equally divided between the riverside and 
landside (centered expansion) or entirely on one side (offset 
expansion). Moderately higher increases will be needed in a small 
segment that accounts for less than 1.2 percent of the total length. In 
areas where existing topography is too steep to allow levee expansion, 
construction solutions, including armored banks (riprap) or retaining 
walls, will be used. Excavation outside the existing right-of-way is 
not anticipated.
    The EA assesses potential environmental impacts of the proposed 
action and the no action alternative. Potential impacts on natural, 
cultural, and other resources were evaluated, and mitigation measures 
were incorporated into the proposed action. A Finding of No Significant 
Impact was issued for the proposed action based on a review of the 
facts and analyses contained in the EA.

Summary of Findings

    Pursuant to the National Environmental Policy Act (NEPA) guidance 
(40 CFR 1500-1508), The President's Council on Environmental Quality 
issued regulations for implementing NEPA, which included provisions for 
both the content and procedural aspects of the required EA. The USIBWC 
completed an EA of the potential environmental consequences of raising 
the Arroyo Colorado Floodway (ACF) 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 ACF levee system, with no impacts to 
biological and cultural resources, water resources, land use, soil, 
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, including associated risks to personal 
safety and property. The levee system will not meet FEMA requirements 
for levee system certification.

Proposed Action

Biological Resources
    Biological resources in the vicinity of the levee systems are 
dominated by agricultural fields, rangelands, and non-native 
grasslands. There are some woody species along the margins of the 
Arroyo Colorado, drainage ditches from irrigation fields, and adjacent 
to borrow pits. The 160-foot wide biological survey corridor, centered 
on the existing levee, includes approximately 221 acres, primarily 
composed of non-native grasslands dominated by buffelgrass and king 
ranch bluestem.
    The proposed action will raise the levee using a centered 
expansion, except in areas south of La Feria reservoir, where an offset 
expansion will be utilized. The proposed levee expansion will remove 
non-native grasslands on the levee slopes and adjacent areas. Native 
grasses will be planted immediately after the completion of the 
project, and the levee expansion will not occur in wooded areas. Less 
than one-half acre of non-jurisdictional wetlands will be affected, but 
no jurisdictional wetlands will be affected by the levee expansion. No 
habitats used by federally or state-listed threatened or endangered 
species will be impacted by the levee expansion.
    In areas adjacent to sensitive areas such as water bodies, levee 
expansion may be altered to an offset expansion toward the riverside of 
the levee to avoid impacting sensitive resources. In areas where the 
existing topography is too steep to allow levee expansion, construction 
solutions, including armored banks, will prevent erosion of the levee 
slopes. The construction solutions will not affect sensitive habitats, 
including wooded areas, habitats for threatened and endangered species, 
or jurisdictional wetlands.
Cultural Resources
    Improvements to the ACF levee system may adversely affect 
prehistoric and historic archaeological resources.

[[Page 28954]]

Some areas adjacent to the toe of the levee contain intact 
archaeological resources. Adverse effects to archaeological resources 
may occur from the use of heavy equipment during levee construction 
that could disturb surface or shallowly buried deposits. Adverse 
effects may also occur to archaeological deposits that will be buried 
by the addition of the fill material on the surface above them. 
Alternatively, levee footprint expansion may protect archaeological 
resources by capping with fill material, preserving those resources in 
place.
    Architectural resources may be adversely affected by levee height 
increases or by expansion of the levee footprint. Potential effects 
include vibration and ground disturbance from the use of heavy 
equipment during construction. Design for levee improvements is 
primarily considering avoidance of the structures as much as possible. 
However, if structures have to be removed or modified, USIBWC will 
consult with the Texas Historical Commission (THC) to determine the 
appropriate level of documentation prior to any modification. In 
addition to documentation, mitigation of impacts to cultural resources 
may include their replacement with ``in-kind'' structures that will 
look and operate the same.
    Native American resources may be affected by the levee 
improvements; consultation with the Native American tribes is ongoing 
to identify resources or concerns regarding the project.
    Under NEPA, there will be no significant impacts (i.e., 
``unresolvable'' adverse effects under National Historic Preservation 
Act [NHPA]) to cultural resources because all cultural resources will 
be identified and evaluated for National Register of Historic Places 
(NRHP) eligibility. Any impacts to National Register of Historic 
Places-eligible resources will be mitigated prior to implementation of 
levee height increases or footprint expansion, in consultation with the 
Texas Historical Commission and Native American Tribes.
Water Resources
    Flood control improvements to the ACF will increase flood 
containment capacity to control the design flood event with a 
negligible increase in water surface elevation. Levee footprint 
expansion will not affect water bodies.
Land Use
    Footprint levee expansion, where required, will take place 
completely within the existing ROW. No urban or agricultural lands will 
be affected.
Soil
    Improvement activity contributing to soil disturbance will include 
geotechnical investigations and adding soil to the top and sides of the 
levee. Levee fill material will come from local commercial sources and 
not from borrow areas in the floodplain. The disturbance of soil will 
occur within areas where soil has been disturbed and modified by prior 
levee construction and maintenance activities. Therefore, alteration of 
soil previously unassociated with the existing levee will not occur.
Community Resources
    In terms of socioeconomic resources, the influx of federal funds 
into Hidalgo and Cameron Counties from the flood control improvement 
area will have a positive but minor local economic impact. The impact 
will be limited to the construction period, and 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 will be required during construction; a 
temporary increase in access road use will be required for equipment 
mobilization to staging areas.
Environmental Health Issues
    Estimated air emissions of five criteria pollutants during 
construction will be discontinuous and represent less than 0.13 percent 
of the annual emissions inventory within the air quality control region 
of Hidalgo, Cameron, and Willacy Counties. There will be a moderate 
increase in ambient noise levels due to construction activities. No 
long-term and regular exposure is expected above noise threshold 
values. A database search indicated that no waste storage and disposal 
sites were within the proposed ACF levee improvement area, and none 
will affect, or be affected by, the levee improvement project.
Best Management Practices
    When warranted due to engineering considerations, or for protection 
of biological or cultural resources, the need for levee footprint 
expansion will be eliminated by levee slope adjustment or use of 
retaining walls or armored banks. 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 cover, the embankment improvement areas will 
be re-vegetated with native herbaceous species. To protect wildlife, 
construction activities will be scheduled to occur, to the extent 
possible, outside the March to August bird migratory season.

Availability

    Single hard copies of the Final Environmental Assessment and 
Finding of No Significant Impact may be obtained by request at the 
above contact information. Electronic copies may also be obtained from 
the USIBWC Home Page at http://www.ibwc.gov/Organization/Environmental/reports_studies.html.

    Dated: June 12, 2009.
Robert McCarthy,
General Counsel.
[FR Doc. E9-14314 Filed 6-17-09; 8:45 am]
BILLING CODE 7010-01-P