J._01_Final_EA_DonnaBrownsville_Levee.pdf

Final Environmental Assessment Improvements to the Donna-Brownsville Levee System

Lead Agency:

United States Section, International Boundary and Water Commission El Paso, Texas

Technical Support:

Parsons Austin, Texas

September 2007

Cooperating Agency:

United States Fish and Wildlife Service

COVER SHEET

ENVIRONMENTAL ASSESSMENT

AND

FINDING OF NO SIGNIFICANT IMPACT

IMPROVEMENTS TO THE

DONNA-BROWNSVILLE LEVEE SYSTEM

Lead Agency: United States Section, International Boundary and Water Commission

Cooperating Agency: United States Fish and Wildlife Service

Proposed Action: Raising approximately 65 miles of the Donna-Brownsville Levee System to meet current requirements for flood control.

Report Designation: Environmental Assessment

Abstract: The USIBWC is considering raising sections of the 65-mile Donna-Brownsville Levee System to meet current flood control requirements. The proposed action would increase the height of the levee up to 2 feet depending on location. The height increase would also result in expansion of the levee footprint by lateral extension of the structure, up to a maximum of 12 feet. Along sections of the Donna-Brownsville Levee System, structural improvements such as slurry walls may be required in segments with seepage potential. A number of natural resources management areas are located near or adjacent to the levee system, including units of the Lower Rio Grande Valley National Wildlife Refuge System and Las Palomas Wildlife Management Areas.

The Environmental Assessment 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 Environmental Assessment.

Donna-Brownsville Levee System Environmental Assessment FONSI

FONSI – Page 1 USIBWC

FINDING OF NO SIGNIFICANT IMPACT

IMPROVEMENTS TO THE DONNA-BROWNSVILLE LEVEE SYSTEM IN THE

LOWER RIO GRANDE FLOOD CONTROL PROJECT

HIDALGO AND CAMERON COUNTIES, TEXAS

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

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 USC 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 Environmental Assessment for the proposed action of partially 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 Peñitas 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.

FONSI – Page 2 USIBWC

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 Lateral A/Retamal Dike 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.

FONSI – Page 3 USIBWC

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 that 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

ENVIRONMENTAL ASSESSMENT

IMPROVEMENTS TO THE DONNA-BROWNSVILLE LEVEE SYSTEM

Lead Agency:

UNITED STATES SECTION,

INTERNATIONAL BOUNDARY AND WATER COMMISSION

UNITED STATES AND MEXICO

Cooperating Agency:

UNITED STATES FISH AND WILDLIFE SERVICE

Technical Support:

PPaarrssoonnss

8000 Centre Park Dr., Suite 200 Austin, Texas 78754

USIBWC Contract IBM04D0002, Task Order IBM05T0022

SEPTEMBER 2007

Environmental Assessment Contents i USIBWC

TABLE OF CONTENTS

ACRONYMS AND ABBREVIATIONS.....................................................................................................v

SECTION 1 PURPOSE OF AND NEED FOR THE PROPOSED ACTION......................................... 1-1

1.1 Purpose of and Need for Action........................................................................................ 1-1

1.2 USIBWC Authority ............................................................................................................ 1-2

1.3 Scope of the Environmental Review............................................................................ ... 1-2

1.4 Environmental Coordination and Compliance Analysis.................................................... 1-4

1.5 Organization of the Environmental Assessment............................................................... 1-6

SECTION 2 DESCRIPTION OF PROPOSED ACTION ...................................................................... 2-1

2.1 LRGRCP Levee System Description ................................................................................ 2-1

2.1.1 Donna-Brownsville Levee System .......................................................................... 2-2

2.1.2 Location of Conservation Lands.............................................................................. 2-2

2.2 Proposed Action................................................................................................................ 2-4

2.3 No Action Alternative ........................................................................................................ 2-5

2.4 Alternatives Considered and Eliminated from Detailed study........................................... 2-6

2.5 Other Actions With Potential Cumulative Impacts ............................................................ 2-6

2.6 Summary Comparison of Environmental Consequences of the Alternatives................... 2-6

2.6.1 No Action Alternative............................................................................................... 2-6

2.6.2 Proposed Action...................................................................................................... 2-6

SECTION 3 AFFECTED ENVIRONMENT........................................................................................... 3-1

3.1 Biological Resources ........................................................................................................ 3-1

3.1.1 Vegetation ............................................................................................................... 3-1

3.1.2 Wildlife..................................................................................................................... 3-5

3.1.3 Threatened and Endangered Species .................................................................... 3-6

3.1.4 Wetlands and Aquatic Habitat................................................................................. 3-6

3.2 Cultural Resources ........................................................................................................... 3-8

3.2.1 Previous Cultural Resources Studies ..................................................................... 3-8

3.2.2 Historical and Prehistoric Archaeological Resources ........................................... 3-10

3.2.3 Historic-age Resources......................................................................................... 3-12

3.2.4 Cemeteries ............................................................................................................ 3-12

3.3 Water Resources ............................................................................................................ 3-14

3.3.1 Regional Flood Control ......................................................................................... 3-14

3.3.2 Water Flow ............................................................................................................ 3-15

3.4 Land Use......................................................................................................................... 3-15

3.4.1 Natural Resources Management Areas................................................................ 3-16

3.4.2 Agricultural Land ................................................................................................... 3-16

3.4.3 Urban Areas .......................................................................................................... 3-16 ii USIBWC

3.5 Community Resources.................................................................................................... 3-16

3.5.1 Socioeconomics .................................................................................................... 3-16

3.5.2 Environmental Justice ........................................................................................... 3-18

3.5.3 Transportation ....................................................................................................... 3-18

3.6 Environmental Health...................................................................................................... 3-19

3.6.1 Air Quality.............................................................................................................. 3-19

3.6.2 Noise ..................................................................................................................... 3-20

3.6.3 Hazardous and Toxic Waste ................................................................................. 3-21

SECTION 4 ENVIRONMENTAL CONSEQUENCES .......................................................................... 4-1

4.1 Biological Resources ........................................................................................................ 4-1

4.1.1 Vegetation ............................................................................................................... 4-1

4.1.2 Wildlife..................................................................................................................... 4-1

4.1.3 Threatened and Endangered Species .................................................................... 4-4

4.1.4 Jurisdictional Wetlands and Aquatic Habitat........................................................... 4-5

4.2 Cultural Resources ......................................................................................................... 4-11

4.2.1 Historic and Prehistoric Archaeological Resources .............................................. 4-11

4.2.2 Historic-age Resources......................................................................................... 4-12

4.3 Water Resources ............................................................................................................ 4-13

4.3.1 Flood Control......................................................................................................... 4-13

4.3.2 Water Flow ............................................................................................................ 4-13

4.4 Land Use......................................................................................................................... 4-13

4.5 Community Resources.................................................................................................... 4-14

4.5.1 Socioeconomics .................................................................................................... 4-14

4.5.2 Environmental Justice ........................................................................................... 4-16

4.5.3 Transportation ....................................................................................................... 4-16

4.6 Environmental Health...................................................................................................... 4-17

4.6.1 Air Quality.............................................................................................................. 4-17

4.6.2 Noise ..................................................................................................................... 4-18

4.6.3 Hazardous and Toxic Waste ................................................................................. 4-18

4.7 Indirect and Cumulative Effects ...................................................................................... 4-18

SECTION 5 BEST MANAGEMENT PRACTICES AND MITIGATION ACTIONS .............................. 5-1

5.1 Engineering Measures ...................................................................................................... 5-1

5.1.1 Best Management Practices ................................................................................... 5-1

5.1.2 Engineering Design Measures................................................................................ 5-1

5.2 Natural Resources ............................................................................................................ 5-2

5.2.1 Best Management Practices ................................................................................... 5-2

5.2.2 Mitigation Measures ................................................................................................ 5-2

5.3 Cultural Resources ........................................................................................................... 5-3

5.3.1 Best Management Practices ................................................................................... 5-3

5.3.2 Mitigation Measures ................................................................................................ 5-3 iii USIBWC

SECTION 6 ENVIRONMENTAL COMPLIANCE AND COORDINATION .......................................... 6-1

6.1 Cooperating agency.......................................................................................................... 6-1

6.2 Consultation ...................................................................................................................... 6-1

6.3 List of Contributors............................................................................................................ 6-2

SECTION 7 REFERENCES................................................................................................................. 7-1

APPENDICES

Appendix A Detailed Maps of Levee Alignment, Right-of-Way and Potential Expansion Area

Appendix B Habitat of Threatened and Endangered Species Potentially Occurring Within Counties Intersecting the Levee System

Appendix C Detailed Maps of Cultural Resources along the Donna-Brownsville Levee Survey Corridor

Appendix D Draft Environmental Assessment Review Comments iv USIBWC

LIST OF TABLES

Table 1.1 Summary of Environmental Coordination and Compliance............................................. 1-5 Table 2.1 Federal, State, and Non-governmental Conservation Tracts along the

Donna-Brownsville Levee System................................................................................... 2-3 Table 3.1 Acreages of Vegetation Communities Along the Donna-Brownsville Levee System...... 3-4 Table 3.2 Wetlands along Donna-Brownsville Levee...................................................................... 3-7 Table 3.3 Known Archaeological Resources and HPAs Identified Within the Survey Corridor .... 3-11 Table 3.4 Historic-age Resources Identified Within or Near the Survey Corridor ......................... 3-13 Table 3.5 Cemeteries Identified Within or Near the Survey Corridor ............................................ 3-13 Table 3.6 Racial Composition of Hidalgo County .......................................................................... 3-17 Table 3.7 Racial Composition of Cameron County ....................................................................... 3-17 Table 3.8 Summary Search Report for the Donna-Brownsville Levee System............................. 3-23 Table 4.1 Impacts to Vegetation within the Donna-Brownsville Levee System .............................. 4-2 Table 4.2 Loaction of Federal, State, and Non-governmental Conservation Tracts Relative to the Donna-Brownsville Levee System........................................................................ 4-3 Table 4.3 Potential Impacts of Donna-Brownsville Levee Improvements on Federally Listed

Threatened and Endangered Species............................................................................. 4-5 Table 4.4 Potentially Impacted Archaeological Resources and HPAs Identified Within the 160-Foot Survey Corridor ....................................................................................... 4-11 Table 4.5 Potentially Impacted Historic-age Resources Identified Within or Near the

Survey Corridor.............................................................................................................. 4-12 Table 4.6 Potential Economic Impacts of Improvements to the Donna-Brownsville

Levee System for Hidalgo County ................................................................................ 4-15 Table 4.7 Potential Economic Impacts of Improvements to the Donna-Brownsville

Levee System for Cameron County ............................................................................. 4-15 Table 4.8 Air Emissions for Improvements to the Donna-Brownsville Levee System................... 4-17 Table 6.1 Preparers of the Environmental Assessment and Technical Studies ............................. 6-2 Table 6.2 Technical Review of the Environmental Assessment...................................................... 6-2

LIST OF FIGURES

Figure 1.1 Location of Donna-Brownsville Levee System ................................................................ 1-3

Figure 3.1 Donna-Brownsville Levee System – Cultural Resources Survey Corridor...................... 3-9

Figure 4.1 Location of Wetlands Within 160-Foot Wide Survey Corridor Levee Miles 0-22, Donna-Brownsville Levee System................................................................................... 4-8

Figure 4.2 Location of Wetlands Within 160-Foot Wide Survey Corridor Levee Miles 22-40, Donna-Brownsville Levee System

Figure 4.3 Location of Wetlands Within 160-Foot Wide Survey Corridor Levee Miles 40-65, Donna-Brownsville Levee System................................................................................... 4-9

Figure 4.3 Location of Wetlands Within 160-Foot Wide Survey Corridor Levee Miles 40-65, Donna-Brownsville Levee System................................................................................. 4-10

Environmental Assessment Acronyms and Abbreviations v USIBWC

ACRONYMS AND ABBREVIATIONS

AQCR air quality control region

BMP best management practices

CERCLIS Comprehensive Environmental Response, Compensation, and Liability Information System

CEQ Council on Environmental Quality CFR Code of Federal Regulations cfs cubic feet per second dbA A-weighted sound level in decibels DNL day-night average sound level

EA environmental assessment EIS environmental impact statement

ERNS Emergency Response Notification System of Spills GENS generator of hazardous waste

GIS geographic information system GPS global positioning system HPA high probability area

IBWC International Boundary and Water Commission LRGFCP Lower Rio Grande Flood Control Project

LRGV Lower Rio Grande Valley LUST leaking underground storage tank

NAAQS National Ambient Air Quality Standards MxIBWC Mexican Section, International Boundary and Water Commission

NEPA National Environmental Policy Act NFRAP no further remedial action planned

NO2 nitrogen dioxide NPL National Priority List

O3 ozone

PM10

particulate matter with an aerodynamic diameter less than or equal to 10 micrometers

PM2.5

particulate matter with an aerodynamic diameter less than or equal to

2.5 micrometers

RCRA Resource Conservation and Recovery Act RM river mile

ROW right-of-way SH state highway

SQG small quantity generator SWP3 storm water pollution prevention plan TASA Texas Archeological Sites Atlas

T&E threatened and endangered TCEQ Texas Commission on Environmental Quality

THC Texas Historical Commission TNRIS Texas Natural Resource Information Service

Environmental Assessment Acronyms and Abbreviations vi USIBWC

TPWD Texas Parks and Wildlife Department TSD transport, storage, and disposal

TxDOT Texas Department of Transportation USACE U.S. Army Corps of Engineers USEPA U.S. Environmental Protection Agency USFWS U.S. Fish and Wildlife Service

USGS U.S. Geological Survey USIBWC United States Section, International Boundary and Water Commission

UST underground storage tank WMA Wildlife Management Area

Environmental Assessment Purpose of and Need for the Proposed Action

1-1 USIBWC

SECTION 1

PURPOSE OF AND NEED FOR THE PROPOSED ACTION

This section discusses the purpose of and need for the proposed action; the authority of the United States Section, International Boundary and Water Commission (USIBWC) to conduct the project as part of its mission; the scope of the environmental review; a summary of environmental compliance requirements; and the organization of this document.

1.1 PURPOSE OF AND NEED FOR ACTION

The USIBWC, in cooperation with the U.S. Fish and Wildlife Service (USFWS), prepared this Environmental Assessment (EA) for the proposed action of raising and/or reconstructing the levee system from the Donna Pump Station in Hidalgo County downstream to Brownsville in Cameron County, Texas. Hereafter, this is referred to as the Donna- Brownsville Levee System. This levee system is part of the Lower Rio Grande Flood Control Project (LRGFCP) that extends approximately 180 miles from the Town of Peñitas in south Texas to the Gulf of Mexico.

The USIBWC identified the Donna-Brownsville Levee System as a priority area for improved flood containment. The levee system extends approximately 65 miles along the Rio Grande, downstream from the Donna Pump Station near the Retamal Dam to an area east of Brownsville, approximately 26 miles upstream of the Gulf of Mexico. The need for levee improvements was determined from hydraulic modeling results indicating that typical height increases of up to 2 feet would be required to meet current design criteria for flood protection along the Donna-Brownsville Levee System (USIBWC 2003a).

In addition to the flood containment evaluation, the Engineer Research and Development Center of the U.S. Army Corps of Engineers (USACE) was commissioned by the USIBWC to assess structural integrity of the entire LRGFCP levee system. The assessment identified a need for structural improvements along a number of segments of the Donna-Brownsville Levee System where seepage control would likely be required. According to the USACE assessment, a 5-mile segment upstream and downstream of the Progreso International Bridge would require structural improvements (USACE 2003).

Figure 1.1 presents an overview of the project area in south Texas. Levee miles along the levee are numbered starting from the upstream reach at the Donna Pump Station.

1-2 USIBWC

1.2 USIBWC AUTHORITY

The International Boundary and Water Commission (IBWC), which before 1944 was known as the International Boundary Commission, was created by the Convention of 1889, and consists of a United States Section and a Mexican Section (MxIBWC). The IBWC was established to apply the rights and obligations the Governments of the United States and Mexico assumed under the numerous boundary and water treaties and related agreements.

Application of the rights and obligations are accomplished in a way that benefits the social and economic welfare of the people on both sides of the boundary and improves relations between the two countries. The mission of the USIBWC has five components, the third of which covers the proposed raising of the Donna-Brownsville Levee System:

• Regulation and conservation of waters of the Rio Grande for use by the United States and Mexico through joint construction, operation, and maintenance of international storage dams and reservoirs and plants for generating hydroelectric energy at the dams, and regulation of the Colorado River waters allocated to Mexico;

• Distribution of waters of the Rio Grande and the Colorado River between the two countries;

• Protection of land along the Rio Grande from floods through levee and floodway projects, and solution of border sanitation and other border water quality problems;

• Preservation of the Rio Grande and Colorado River as the international boundary; and

• Demarcation of the land boundary.

1.3 SCOPE OF THE ENVIRONMENTAL REVIEW

Federal agencies are required to take into consideration the environmental consequences of proposed and alternative actions in the decision-making process under the National Environmental Policy Act (NEPA) of 1969, as amended. The President’s Council on Environmental Quality (CEQ) issued regulations to implement NEPA that include provisions for both the content and procedural aspects of the required environmental analysis. In 1978, the CEQ issued regulations implementing the process (40 Code of Federal Regulations [CFR] 1500-1508).

The USIBWC regulations for implementing NEPA are specified in Operational Procedures for Implementing Section 102 of the National Environmental Policy Act of 1969, Other Laws Pertaining to Specifics Aspects of the Environment and Applicable Executive Orders (46 FR 44083, September 2, 1981; Appendix 501-A). These federal regulations establish both the administrative process and substantive scope of the environmental impact evaluation designed to ensure that deciding authorities have a proper understanding of the potential environmental consequences of a contemplated course of action. The CEQ regulations require that an EA:

Levee Mile 1

Levee Mile 65

Levee Mile 60

Levee Mile 50

Levee Mile 40

Levee Mile 30

Levee Mile 20 Levee Mile 10

Figure 1.1 Location of the Donna - Brownsville Levee System

Donna - Brownsville Levee System EA International Boundary and Water Commission, United States Section

160-Foot Wide Survey Corridor Potential Levee Expansion Area USFWS National Wildlife Refuge Tracts TPWD Wildlife Management Areas

¹

Rio Grande

San Fernando

Pilo n Sa n J uan

Rio Salado

Rio Grande

Tamaulipas

Nuevo Leon

Texas

Ciudad Victoria

Corpus Christi

0 4 8 122 Miles

0 5 10 15 202.5 Kilometers

Levee System Start Point

Levee System End Point

Retamal Dam

1-4 USIBWC

• Briefly provide evidence and analysis to determine whether the proposed action might have significant effects that would require preparation of an environmental impact statement (EIS). If analysis determines that the environmental impacts would not be significant, a Finding of No Significant Impact is prepared;

• Facilitate the preparation of an EIS, when required; or

• Aid an agency’s compliance with NEPA when no EIS is necessary.

This EA identifies and evaluates the potential environmental consequences that may result from implementation of the Proposed Action and No Action alternative. It also characterizes the affected environment and describes, when required, mitigation measures to prevent or minimize impacts to environmental resources. The following resource areas are analyzed for potential environmental consequences: biological resources; cultural resources; water resources; land use; and community resources (socioeconomics, environmental justice, and transportation). Environmental health issues are also evaluated (air quality, noise, and hazardous and toxic waste).

Analyses of environmental resources for the affected environment and environmental consequences are based on a potential expansion corridor around the existing Donna- Brownsville Levee System.

Analyses of environmental consequences also include potential indirect impacts adjacent to the levee corridor and the region depending on the resource and its relationship to the proposed action and alternatives. Reference values for air quality, cultural resources, socioeconomics, and environmental justice are evaluated on a regional basis (county level).

Results of studies conducted in support of the EA preparation were reported in the document Technical Support Studies for the Environmental Assessment of Flood Control Improvements to the Donna-Brownsville Levee System (Parsons 2007). Findings of these studies were used to document baseline conditions for biological resources, cultural resources, wetlands, and waste storage and disposal. The report also documents potential performance of the levee system based on hydraulic model simulations, and an evaluation of environmental compliance requirements and coordination activities.

The most recent information is used for the impact analyses. Impacts are considered for the time period covered under the construction period and subsequent flood control improvement conditions. Potential environmental consequences of the Donna-Brownsville Levee System for each resource area evaluated are discussed separately in Section 4 of this EA.

1.4 ENVIRONMENTAL COORDINATION AND COMPLIANCE ANALYSIS

Table 1.1 is a summary of regulatory and/or permitting requirements potentially applicable to improvements under consideration, regulation or compliance issue, and anticipated level of environmental coordination.

1-5 USIBWC

Table 1.1 Summary of Environmental Coordination and Compliance

Agency or Organization

Regulation or Issue Level of USIBWC Coordination

Biological Resources

U.S. Fish and Wildlife Service

(USFWS)

Endangered Species Act of 1973 (Public Law 93-205) and amendments of 1988 (Public Law 100-478) USFWS Coordination Act (916 USC 661, et seq.)

Section 7 of the Act requires formal consultation if significant adverse impacts to federally-listed threatened and endangered species, and migratory birds, could occur.

Consultation with USFWS regarding impacts on various units of the Lower Rio Grande Valley (LRGV) National Wildlife Refuge adjacent to the levee systems.

Texas Parks and Wildlife Department

(TPWD)

Chapters 67 and 68 of the TPWD Code, and Section 65.171-65.184 of the Texas Administrative Code

Coordination concerning potential impacts of the levee raising project to wildlife, including units of the Las Palomas Wildlife Management Areas

National Audubon Society Sabal Palms Center Coordination concerning potential impacts

Cultural Resources Texas Historic Commission

(THC)

National Historic Preservation Act of 1966, as amended (16 USC 470, et seq.)

Compliance with Section 106 requirements for potential impacts to archaeological and historic resources.

Water Resources

U.S. Army Corps of Engineers

(USACE)

Section 10 of the Rivers and Harbors Act of 1899 Section 404 of the Clean Water Act (33 USC 1344)

Permit application if water of the United States are affected. Mitigation plan and permit application for potential impacts to wetlands.

Texas Commission on Environmental Quality (TCEQ)

Section 401 of the Clean Water Act (33 USC 1344);

Section 26.040 of Texas Water Code

Section 401 Certification: conditions and mitigation measures may be stipulated for the 401 permit;

coordination is typically a function of the USACE permitting process.

Other Issues Natural Resources Conservation Service

Farmland Protection Policy Act Determination that no unique or prime farmland would be affected by the federal project.

U.S. Customs and Border Patrol Levee Road Usage Coordination during construction activities.

Hidalgo County Progreso International Bridge Coordination for construction work upstream and downstream of the bridge.

Irrigation Districts Modifications to intake channels or construction along irrigation canals

Progreso Irrigation Districts in Hidalgo County: levee construction along segments of the Donna-Brownsville Main Canal.

La Feria, Adams Garden, Harlingen, San Benito, Santa Maria, Cameron County Irrigation District No. 16, Los Fresnos, and Brownsville in Cameron County: levee construction along segments of the Donna-Brownsville Main Canal.

1-6 USIBWC

1.5 ORGANIZATION OF THE ENVIRONMENTAL ASSESSMENT

This Environmental Assessment is composed of the following sections:

Section 1 identifies the purpose of and need for the Proposed Action, defines the scope of the environmental review, and provides an environmental coordination and compliance analysis.

Section 2 describes the Proposed Action and No Action Alternative, and summarizes potential environmental impacts.

Section 3 presents information on the affected environment, providing a basis for analyzing the impacts of the Proposed Action.

Section 4 analyzes the environmental consequences of the flood control improvements of the Donna-Brownsville Levee System.

Section 5 describes best management practices for construction and potential mitigation actions.

Section 6 describes the consultation process and lists persons and agencies consulted, and contributors to the EA preparation.

Section 7 is a list of cited references and source documents relevant to preparation of the

EA.

Support documentation is provided in Appendix A (detailed maps of levee alignment, right-of-way, and potential expansion area), Appendix B (list of threatened and endangered species potentially present within Hidalgo and Cameron Counties), and Appendix C (cultural resources maps). Appendices are provided in the attached CR-ROM, along with the following documents:

• Technical Support Studies Report, Environmental Assessment of Alternatives for Improved Flood Control of the Donna-Brownsville Levee System, February 2007.

Document prepared by Parsons, Austin, Texas for the USIBWC in support of the EA preparation.

• Archaeological and Historic Resources Evaluation of the Proposed Improvements to the Donna to Brownsville Levee System, Cameron and Willacy Counties, Texas.

April 2007. Scott A. Sundermeyer, Sherry N. DeFreece Emery, and Charles D.

Neel, Document prepared by LopezGarcia Group, Dallas, Texas for Parsons in support of the EA preparation.

Environmental Assessment Description of Proposed Action

2-1 USIBWC

SECTION 2

DESCRIPTION OF PROPOSED ACTION

This section presents a description of the Proposed Action for improvements of the Donna-Brownsville Levee System. A summary of potential environmental impacts, subsequently discussed in Section 4, is provided at the end of Section 2. An overview of the Donna-Brownsville Levee System is presented in Figure 1.1. Appendix A presents detailed maps of levee alignment, right-or-way, and potential expansion area.

2.1 LRGFCP LEVEE SYSTEM DESCRIPTION

The LRGFCP consists of the river channel, flood levees in each country, two diversion dams, and off-river floodways in Mexico and the United States. Other components of the project include irrigation weirs, pump intakes, highway and railroad bridges, river gauges, and farm levees. Some river straightening took place between 1976 and 1977 on a 9,000-foot length of river upstream of Hidalgo and Reynosa.

The LRGFCP levee system extends approximately 180 miles from the Town of Peñitas in south Texas to the Gulf of Mexico. The LRGFCP was constructed to protect urban, suburban, and highly developed irrigated farmlands in the Rio Grande/Rio Bravo delta from floods, in both the United States and Mexico. The LRGFCP includes 102 miles of grass-covered earthen structures along the United States margin of the Rio Grande and Anzalduas Diversion Dam.

The dam diverts floodwaters into a United States interior floodway system (Banker/Main Floodway) flanked by 168 miles of levees. A second dam, Retamal Diversion Dam, routes Rio Grande floodwaters into Mexico’s interior floodway.

The distance between the United States and Mexican levees along the Rio Grande ranges from approximately 400 feet to 3 miles. The depth of the river channel varies from 1 to 15 feet.

A total of 270 miles of levees have been built on the United States portion of the project: 102 miles along the Rio Grande, and 168 miles in the off-stream floodways system. The off-river levees have an average height of about 15 feet. The on- and off-river levees have an average base width of 90 to 120 feet, and an average crown width of 14 to 16 feet. Levee separation is between 600 feet to 1 mile.

The two diversion dams, Anzalduas and Retamal, were constructed with the objective of diverting flood flows in the off-river floodway systems of the United States and Mexico, respectively. Two diversion dams, Anzalduas Dam and Retamal Dam, are jointly operated by the USIBWC and MxIBWC. The interior floodway system in the United States has a total area of 27,013 acres between the levees in Hidalgo, Cameron, and Willacy Counties.

The LRGFCP contains a variety of features for protection of the LRGV of Texas, including the Rio Grande main stem, an Interior Floodway System, and the Anzalduas and Retamal Diversion Dams. The United States portion of the LRGFCP is operated to convey excess floodwaters of the Rio Grande Valley to the Gulf of Mexico through the river and

2-2 USIBWC

United States interior floodways. Anzalduas Dam is operated to divert water as required by the Treaty of February 3, 1944, “Utilization oSectionf Waters of the Colorado and Tijuana Rivers and of the Rio Grande” (TS994; 59 Stat. 1219). Flood operations of the LRGFCP also involve close coordination of the USIBWC and MxIBWC in the operation of two upstream reservoirs (Amistad and Falcon) to control floodwaters reaching the LRGFCP area. The two sections work closely on the division of excess floodwaters diverted into each country’s interior floodway systems.

2.1.1 Donna-Brownsville Levee System

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. The levee system is a component of the LRGFCP. The Donna-Brownsville Levee System is illustrated in Figure 1.1.

More detailed information by individual levee segments is presented in Appendix A.

The levee ROW runs primarily through agricultural areas, and irrigation canals border significant reaches of the levee system. The Progreso Irrigation District is located in Hidalgo County. The Santa Maria; La Feria, Adams Garden, Harlingen, San Benito, Cameron County Irrigation District No. 16, Los Fresnos, and Brownsville irrigation districts are located in Cameron County. Several large tracts of land have been set aside for natural resource management activities. These include several tracts of the Lower Rio Grande Valley (LRGV) National Wildlife Refuge, managed by the USFWS, several tracts of the Las Palomas Wildlife Management Area (WMA), managed by the Texas Parks and Wildlife Department (TPWD), and the Sabal Palms Center, managed by the National Audubon Society. Refuge lands are found along 8.9 miles of levee system, primarily on the riverside of the levee. Additional land tracts near the levee have been acquired by various irrigation districts or residential subdivisions.

2.1.2 Location of Conservation Lands

Land set aside specifically for natural resource management activities are important for threatened and endangered (T&E) species recovery, habitat preservation, and the emerging eco-tourism economy in South Texas. The LRGV National Wildlife Refuge maintains the majority of tracts along the levee systems, as well as TPWD (WMAs and state park units), Texas Chapter of the Nature Conservancy, and National Audubon Society. Geographic Information System (GIS) information provided by USFWS and TPWD, as well as field observations during November 2006 and January 2007 surveys identified conservation lands along the 160-foot wide survey corridor. Table 2.1 lists various LRGV National Wildlife Area tracts, WMAs, and a single National Audubon Society tract along the Donna–Brownsville levee system. Only three LRGV National Wildlife Refuge tracts are adjacent to the potential levee expansion area (at mile markers 22.0, 37.5, and 38.5). No expansion adjacent to these refuge tracts would encroach beyond the existing areas with herbaceous vegetation.

2-3 USIBWC

Table 2.1 Federal, State, and Non-governmental Conservation Tracts along the Donna- Brownsville Levee System

Tract Size Location Along Levee System

Approximate Length Adjacent to the Levee Adjacent to Potential Levee

Expansion Area

USFWS Lower Rio Grande Valley National Wildlife Refuge System* 258-Acre Tract Mile Marker 4.0, riverside 750 Feet No 186-Acre Tract Mile Marker 8.0, riverside 1,700 Feet No 32-Acre Tract Mile Marker 11.0, both sides 1,800 Feet No 556-Acre Tract Mile Marker 15.0, riverside 5,200 Feet No 47-Acre Tract Mile Marker 21.0, riverside 1,800 Feet No

269-Acre Tract Mile Marker 22.0 Riverside and landside 4,000 Feet

Yes; expansion is within levee ROW;

in few locations acquisition maybe required for a 20-foot wide service corridor adjacent to the levee toe

38-Acre Tract Mile Marker 27.5 Riverside and landside 1,200 Feet No

1-Acre Tract Mile Marker 34.5, riverside 470 Feet No 1-Acre Tract Mile Marker 34.5, riverside 450 Feet No

175 Acre Tract Mile Marker 37.5 Riverside and landside 1,000 Feet

Yes; expansion is within levee ROW except where some acquisition maybe needed for a service corridor

297-Acre Tract Mile Marker 38.5 Riverside and landside 5,700 Feet

Yes; expansion is within levee ROW except where some acquisition maybe needed for a service corridor

30-Acre Tract Mile Marker 46.0, riverside 1,500 Feet No 339-Acre Tract Mile Marker 48.0 Landside 7,800 Feet No 297-Acre Tract Mile Marker 55.0, riverside 1,500 Feet No

423-Acre Tract Mile Marker 58.0 Riverside and landside 4,500 Feet No

184-Acre Tract Mile Marker 62.0, landside 6,100 Feet No 336-Acre Tract Mile Marker 62.0, riverside 2,500 Feet No

TPWD Wildlife Management Areas** Las Palomas WMA (3-Acre Champion Tract) Mile Marker 2.5, landside 200 Feet No

Las Palomas WMA (21-Acre Gonzales Tract) Mile Marker 17.0, landside 600 Feet No

Las Palomas WMA (62-Anacua Tract) Mile Marker 17.5, landside 2,700 Feet No

Las Palomas WMA (139-Acre Anacua Tract)

Mile Marker 18.5 Riverside and landside 5,200 Feet No

National Audubon Society, Texas Chapter***

Sabal Palms Center (557-Acre Tract) Mile Marker 59.0, riverside 2,500 Feet No

* National Wildlife Refuge tract boundaries were obtained from USFWS GIS online data (USFWS 2003).

** WMA boundaries were obtained from Texas Natural Resource Information Service GIS data clearinghouse

(TNRIS 2004).

*** Sabal Palms Center tract boundary was obtained from field verification (Ferrell 2007, personal communication)

2-4 USIBWC

Urban development in the vicinity of the Donna-Brownsville Levee System is found primarily along the City of Brownsville and the unincorporated Towns of Progreso, Relampago, Santa Maria, Los Indios, Carricitos, La Paloma, El Calaboz, Ranchito, San Pedro, and Palm Grove. No residential developments are located or allowed, within the levee system

ROW.

The existing levee is a raised trapezoidal compacted-earth structure with a crown width of 16 feet, a typical height ranging from 6 to 10 feet, and an approximate 3:1 side slope ratio (units of horizontal run in feet per foot of vertical rise). The existing levee footprint ranges from 50 to 80 feet, depending on location. A typical levee cross-section is shown in the diagram below.

The levee crown is an unpaved service road with restricted public access throughout most of the Donna-Brownsville Levee System.

2.2 PROPOSED ACTION

The Proposed Action would increase flood containment capacity of the Donna-

Brownsville Levee System by raising the height of the existing compacted earth levee up to 2 feet to meet the 3-foot freeboard requirement. The increase in levee height would also expand the levee footprint by lateral extension of the structure. For a typical levee cross-section, shown in the diagram below (8 feet elevation, 3:1 slope, and 16-foot crown), a 4-foot increase in levee height would result in a 24-foot offset increase of the footprint. A current footprint width value of 64 feet would expand to 88 feet as a result of the increased levee height.