J.04_Ch_I _II _III_ _IV_text_Rio_Grande_PEIS_Dec_26th.pdf

Final Programmatic Environmental Impact Statement Improvements to the USIBWC Rio Grande Flood Control Projects along the Texas-Mexico Border

January 2008 Technical Support:

PARSONS

Austin, Texas

Lead Agency:

United States Section International Boundary and

Water Commission El Paso, Texas

Cooperating Agencies:

U.S. Army Corps of Engineers Galveston District, Texas

U.S. Bureau of Reclamation El Paso Field Division, Texas

U.S. Fish and Wildlife Service Corpus Christi, Texas

Ecological Services Field Office

Cover Sheet

PROGRAMMATIC ENVIRONMENTAL IMPACT STATEMENT

IMPROVEMENTS TO THE USIBWC RIO GRANDE FLOOD CONTROL PROJECTS

ALONG THE TEXAS-MEXICO BORDER

( ) Draft ( X) Final

Lead Agency

United States Section, International Boundary and Water Commission

(USIBWC)

El Paso, Texas

Cooperating Agencies

United States Bureau of Reclamation United States Fish and Wildlife Service U.S. Army Corps of Engineers

Abstract

The USIBWC anticipates the need to improve capabilities or functionality of three Rio Grande flood control projects (FCP) located in the Texas-Mexico border:

Rectification FCP, Presidio FCP, and Lower Rio Grande FCP.

Improvement measures associated with the project core mission of flood protection, boundary stabilization, and water delivery are evaluated under the Enhanced Operation and Maintenance (EOM) Alternative. Additional measures intended to improve water use, quality, and conservation are considered under the Integrated Water Resources Management (IWR) Alternative; and measures in support of local or regional initiatives for increased utilization of the project or to improve environmental conditions are evaluated under the Multipurpose Project Management (MPM) Alternative.

This Programmatic Environmental Impact Statement (PEIS) evaluates potential environmental consequences of alternatives under consideration for improvement of the three flood control projects. The USIBWC will apply the programmatic evaluation as an overall guidance for the anticipated implementation of future environmental evaluations of individual improvement projects, implementation of which could be possible within a 20-year timeframe.

Other Requirements Served

This PEIS is intended to serve other environmental review and consultation requirements pursuant to 40 CFR 1502.25(a).

Date of Final PEIS availability to USEPA and the Public:

January 4, 2008

Comments should be directed to:

Mr. Daniel Borunda Environmental Management Division

USIBWC

4171 North Mesa St., C-100 El Paso, Texas 79902

Programmatic Environmental Impact Statement Executive Summary

ES-1 USIBWC

EXECUTIVE SUMMARY

Purpose of and Need for Action

The USIBWC is evaluating a range of alternatives for maintenance activities and future improvements to three of its flood control projects located in the Rio Grande along the Texas- Mexico border. Those flood control projects, the locations of which are identified in Figure ES-1, are:

• Rio Grande Rectification Project (Rectification FCP) extending 84.4 river miles along the Rio Grande, downstream from American Diversion Dam to Fort Quitman, Texas.

• Presidio-Ojinaga Flood Control Project (Presidio FCP) extending over 13.1 river miles of the Rio Grande near Presidio, Texas.

• Lower Rio Grande Flood Control Project (Lower Rio Grande FCP) extending 186 river miles on the Rio Grande, from Peñitas, Texas to the Gulf of Mexico, and including 120 miles of interior floodway.

This Programmatic Environmental Impact Statement (PEIS) was prepared to evaluate maintenance improvement alternatives that would allow USIBWC to minimize potential environmental impacts and take advantage of environmental opportunities while meeting its mandate for flood protection, boundary stabilization, and water delivery.

Over a 20-year planning period, the USIBWC anticipates the need to improve capabilities or functionality of the flood control projects. While some improvements to the flood control projects are already in a planning stage or have been developed at a conceptual level, others represent measures considered feasible but not currently envisioned for implementation.

Known or anticipated improvements are typically associated with the core mission of flood control, boundary stabilization, and water delivery. Other improvements are associated with additional goals adopted by the USIBWC in support of the projects’ core mission. Those goals include improvements in water use, quality, or conservation and multipurpose utilization of the projects in support of local or regional initiatives for recreational use or environmental improvement.

The USIBWC will apply the programmatic evaluation of potential impacts as an overall guidance for future environmental evaluations of individual improvement projects whose implementation is anticipated or possible within a 20-year timeframe. Once any given improvement project is identified for future implementation, site-specific environmental documentation will be prepared based on project specifications and PEIS findings.

Lower Rio Grande Flood Control Project

Presidio-Ojinaga Flood Control Project

Rio Grande Rectification Project

G ulf of California

Gulf of Mexico

El Paso

Texas

Arizona New Mexico

Oklahoma

Arkansas

Louisiana

Missouri

Sonora

Chihuahua

Durango

Coahuila De Zaragoza

Sinaloa Nuevo Leon

Tamaulipas

Baja California Sur

Zacatecas

Ri o G ra nd e

Nazas

Con ch os Rio Salado

Yaqui

Ri o

So no ra

Rio Fuerte

Bavispe Papigochic

M octezum a Yaqui

Red Brazos

Pe co sRi o

G ra nd e

Gila

Canadian

Salt

Arkansas

Saltillo

Chihuahua

Monterrey

Hermosillo

Tulsa

Austin

Tucson Dallas

Houston

Phoenix

Fort Worth

San Antonio

Albuquerque Oklahoma City

Corpus Christi

110°0'0"W

110°0'0"W

105°0'0"W

105°0'0"W

100°0'0"W

100°0'0"W 95°0'0"W

95°0'0"W

25°0'0"N

25°0'0"N

30°0'0"N

30°0'0"N

35°0'0"N

35°0'0"N

Figure ES-1 Location of USIBWC Flood Control Projects

Along the Texas-Mexico Border Programmatic EIS

International Boundary and Water Commission, United States Section

¹ 0 100 200 300 400 50050 Miles

0 100 200 300 400 50050 Kilometers

ES-3 USIBWC

Alternatives Considered in Detail

A summary of potential measures under consideration is presented in Table ES-1. For the PEIS evaluation, measures identified as feasible were organized into three action alternatives that reflect the following project goals:

1. Measures associated with projects’ mission of flood control, boundary stabilization, and water delivery, evaluated under the Enhanced Operation and Maintenance Alternative;

2. Measures intended to improve water use, quality, and conservation, considered under the Integrated Water Resources Management Alternative; and

3. Measures in support of local or regional initiatives for increased utilization of the project or to improve environmental conditions, evaluated under the Multipurpose Project Management Alternative.

Table ES-1 Potential Changes Relative to Current O&M Practices

FLOOD CONTROL PROJECT

Rectification Presidio LRGFCP

FLOOD CONTROL SYSTEM ALONG THE RIO GRANDE

Levee Improvements Levee height increase X X X Structural levee improvements X X X Partial relocation within ROW or new flood easements X

Changes in Floodway Management Changes in vegetation removal and timing/extent of mowing X Restricted Use Zones X

Changes in Channel Maintenance Sediment removal and disposal X X X Shore/aquatic vegetation removal X

INTEGRATED WATER RESOURCES MANAGEMENT

Water Use and Conservation Salt cedar management X X Irrigation BMPs to increase water delivery efficiency X Support maintenance of irrigation structures and drains X

Water Quality Modified irrigation drain maintenance X X

MULTIPURPOSE PROJECT MANAGEMENT

Jurisdictional Floodway Use Parks, nature trails, recreational areas X X Control of invasive/exotic species X X

Cooperative Agreements and Regional Initiatives Vegetation removal and timing/extent of mowing X Control of invasive/exotic species outside ROW X X X Wildlife habitat conservation inside or outside ROW X X X Flow regime modification to provide year-round baseflow X Upstream sediment control (dams, traps) X

ES-4 USIBWC

Summary of Environmental Consequences

The PEIS compares potential environmental consequences of the three action alternatives with those expected from continued use of current management and operational practices evaluated under the No Action Alternative. Impacts were evaluated for the following resource areas: water, biological, cultural resources, socioeconomic resources, land use, and environmental health (noise, air quality, environmental hazards). A summary comparison of potential environmental consequences of the alternatives by resource area, with general application to the three flood control projects under evaluation, is presented in Table ES-2.

The Multipurpose Project Management Alternative was selected as the preferred option for implementation of improvements to the Rectification FCP, Presidio FCP and Lower Rio Grande FCP. This selection is consistent with the core project mission of flood control and water delivery, and supports improvements in water quality and water conservation as well as regional initiatives for habitat improvement and management of natural resources.

Participation in such initiatives would be conducted as cooperative agreements with the proposing agency or organization.

ES- 5 USIBWC

Table ES-2 Summary of Environmental Consequences of Alternatives for Improvement of the Flood Control Projects

No Action Alternative Enhanced Operation and

Management (EOM) Alternative

Integrated Water Resources Management

(IWR) Alternative

Multipurpose Project Management

(MPM) Alternative

Water Resources Current containment may be insufficient to fully control severe floods.

Levee system would increase flood containment capacity to control severe floods.

Flood containment capacity would improve, as well as water resource utilization.

Flood containment capacity would improve; a moderate increase in water use by floodway vegetation would be offset by improved use of water resource.

Biological Resources

The on-going mowing of the levee slopes and floodway would maintain this habitat as relatively low quality for wildlife use.

There would be no changes relative to current conditions in terms of potential impacts to wildlife habitat, aquatic ecosystems, wetlands, or unique or sensitive areas.

Little or no changes are expected from the EOM Alternative in terms of vegetation, wildlife habitat, aquatic ecosystems, wetlands, or unique or sensitive areas. Non-native grasses removed by levee improvements would re-establish after construction.

The relatively low-quality floodway habitats would be maintained.

Potential effects on wetlands would be minimized.

Salt cedar management and revegetation would increase habitat for native plant species and wildlife, including threatened and endangered species.

Impacts to wetlands, aquatic ecosystems, and other biological resources would be similar to those of the No Action and EOM Alternatives.

Regional habitat revegetation and conservation initiatives outside the levee corridor would provide additional habitat for native plant species and wildlife, including threatened and endangered species;

Improved sediment management and habitat development would improve aquatic ecosystems.

Land Use

Existing residential communities, agricultural lands, and recreational uses would be maintained.

Effects, as in the No Action Alternative. Floodway management changes, including increased U.S. Border Patrol operations, would limit some recreational uses.

Similar to those of the No Action and EOM Alternatives.

Beneficial effects would be expected from multi-jurisdictional, cooperative agreements to promote recreational opportunities, including trail systems.

Cultural Resources No additional impacts on historical and archaeological resources.

Historical structures and/or archaeological resources could be affected by changes to the levee system configuration.

Similar to those of the EOM Alternative. Impacts would depend on the extent of the proposed projects.

Similar to those of the EOM Alternative.

ES- 6 USIBWC

No Action Alternative Enhanced Operation and

Management (EOM) Alternative

Integrated Water Resources Management

(IWR) Alternative

Multipurpose Project Management

(MPM) Alternative

Socioeconomic Resources

No change relative to current operations on impacts to regional economics, environmental justice, and transportation.

Temporary input of project funds would not significantly improve regional economics. Adverse effects to minority and low-income populations are not expected.

Increased use of main roadways and access roads would be minor and limited to project duration.

Impacts would be the same as the EOM Alternative. Roadway utilization would depend on the extent of proposed initiatives.

Impacts would be the same as the EOM Alternative.

Environmental Health (Noise, Air Quality, and environmental hazards)

Emissions generating activities and noise generation would be the same as the current ongoing activities. There would be no impacts to public health and environmental hazards.

Regional air quality would not be impacted. Small increases in emissions and noise generation would be temporary during construction activities. There would be no impacts to public health and environmental hazards.

Impacts would be the same as the EOM Alternative. Roadway utilization would depend on the extent of proposed initiatives.

Impacts would be the same as the EOM Alternative.

IMPROVEMENTS TO USIBWC RIO GRANDE FLOOD

CONTROL PROJECTS ALONG THE TEXAS-MEXICO

BORDER

PREAMBLE

This is a Programmatic Environmental Impact Statement (PEIS) for future improvement alternatives of three flood control projects operated and maintained by the United States Section, International Boundary and Water Commission (USIBWC) along the Texas-Mexico border: the Rio Grande Rectification Project, the Presidio-Ojinaga Flood Control Project, and the Lower Rio Grande Flood Control Project.

The PEIS is organized into four chapters: a Program Background and Alternatives Chapter and three individual chapters for each flood control project.

Chapter I, Program Background and Alternatives, presents background information on the PEIS objective and scope of the environmental review; describes the alternatives and the basis for their development; and documents the environmental compliance and coordination process.

Chapter I is composed of four sections, as follows:

Section 1, Purpose of and Need for Action, indicates the PEIS objective, scope of the environmental review, and a brief description of the flood control projects.

Section 2, Alternatives Formulation, describes the development of the alternatives based on opportunities and constraints, identifies potential project improvement measures, and defines alternatives based on project objectives.

Section 3, Environmental Compliance and Coordination, documents the consultation process followed to develop the alternatives and evaluate potential environmental consequences. The Final PEIS includes a section discussing written comments received during a 45-day public review of the Draft PEIS, as well as oral comments provided during three public hearings held in the Cities of El Paso, Presidio, and McAllen, Texas (August 21, 22 and 28, 2007, respectively).

Section 4, References, lists technical support documents used in the PEIS preparation, as well as other reference documentation cited throughout the PEIS. Key environmental documentation previously prepared by the USIBWC, as well as other key technical support documents, are provided in Appendices C, D and E (CD-ROM).

Chapters II, III and IV provide an assessment of environmental consequences of implementing anticipated or possible measures for improvement of each of the flood control projects. Each chapter contains the following three sections:

Section 1, Description of Alternatives, identifies measures associated with four alternatives for improvement of the flood control projects selected or the PEIS evaluation: a No Action Alternative, the continued implementation of current operation and maintenance (O&M) practices, and three action alternatives: Enhanced Operation and Maintenance (EOM) Alternative, Integrated Water Resources Management (IWR) Alternative; and Multipurpose Project Management (MPM) Alternative.

Section 2, Affected Environment, provides the basis for evaluation of potential impacts in the areas of water, biological, land use, cultural and socioeconomic resources, as well as environmental health issues (air quality, noise and environmental hazards).

Section 3, Environmental Consequences, is an analysis of potential effects associated with implementation of each alternative. This analysis is presented by resource area, following the sequence used in describing the affected environment. A discussion of selection of the MPM Alternative as the preferred option for long-term implementation of future Rio Grande FCP improvement projects is presented in Sections 3.8 of Chapters II, III and IV.

Support documentation is provided in Appendices, as follows:

A. Written and Public Hearing Comments on Draft PEIS

B. Responses to Draft PEIS Comments

C. Programmatic EIS Documentation (CD-ROM format)

D. USIBWC Environmental Evaluation Documents (CD-ROM format)

E. Technical Support Documents (CD-ROM format)

IMPROVEMENTS TO USIBWC RIO GRANDE FLOOD CONTROL

PROJECTS ALONG THE TEXAS-MEXICO BORDER

CHAPTER I

PROGRAM BACKGROUND AND ALTERNATIVES

Programmatic Environmental Impact Statement Chapter I – Program Background and Alternatives

12/26/2007 i USIBWC

CHAPTER I

TABLE OF CONTENTS

ACRONYMS AND ABBREVIATIONS....................................................................................................iii ENGLISH TO METRIC UNITS CONVERSIONS ....................................................................................iv SECTION 1 PURPOSE OF AND NEED FOR ACTION ...................................................................... 1-1

1.1 Background....................................................................................................................... 1-1

1.1.1 Scope of the Environmental Review ....................................................................... 1-1

1.1.2 USIBWC Authority................................................................................................... 1-2

1.2 Purpose of and Need for Action........................................................................................ 1-2

1.3 Description of Flood Control Projects ............................................................................. 1-4

1.3.1 Flood Control Projects Overview............................................................................. 1-4

1.3.2 Rio Grande Rectification Project ............................................................................. 1-4

1.3.3 Presidio-Ojinaga Flood Control Project................................................................... 1-5

1.3.4 Lower Rio Grande Flood Control Project ................................................................ 1-6

SECTION 2 FORMULATION OF ALTERNATIVES ............................................................................ 2-1

2.1 Initial Identification of Potential Measures ........................................................................ 2-1

2.2 Basis for Alternatives Formulation .................................................................................... 2-2

2.2.1 Flood Control........................................................................................................... 2-3

2.2.2 Water Delivery and Boundary Preservation............................................................ 2-4

2.2.3 Project Scale and Diversity ..................................................................................... 2-4

2.2.4 Environmental Initiatives and Cooperative Agreements ......................................... 2-4

2.2.5 Mitigation and Compensation Measures................................................................. 2-5

2.3 Definition of Alternatives by Project Objective .................................................................. 2-6 SECTION 3 ENVIRONMENTAL COMPLIANCE AND COORDINATION .......................................... 3-1

3.1 Public and Agency Consultation ....................................................................................... 3-1

3.1.1 Scoping Meetings.................................................................................................... 3-1

3.1.2 Notifications to Agencies, Elected Officials, Organizations, and Individuals .......... 3-2

3.2 PEIS Preparation and Review .......................................................................................... 3-2

3.2.1 Cooperating Agencies............................................................................................. 3-2

3.2.2 PEIS Preparation .................................................................................................... 3-3

3.2.3 Draft PEIS Public Review........................................................................................ 3-4

SECTION 4 PEIS REFERENCES........................................................................................................ 4-1

12/26/2007 ii USIBWC

LIST OF TABLES

Table I-1 Summary of Features of the Flood Control Projects (Sturdivant et al. 2004).................. 1-4 Table I-2. Potential Changes Relative to Current O&M Practices ................................................... 2-2 Table I-3 Opportunities and Constraints for Project Improvement ................................................. 2-3 Table I-4 Measure Organization by Categories used in the Formulation of Alternatives ............... 2-7 Table I-5 Technical Personnel Responsible for PEIS Preparation ................................................. 3-3 Table I-6 PEIS Reviewers............................................................................................................... 3-4

LIST OF FIGURES

Figure 1 Location of Flood Control Projects .................................................................................. 1-7 Figure 2 Upper Reach of the Rectification Flood Control Project.................................................. 1.8 Figure 3 Lower Reach of the Rectification Flood Control Project.................................................. 1-9 Figure 4 Presidio-Ojinaga Flood Control Project Location .......................................................... 1-10 Figure 5 Presidio-Ojinaga Flood Control Project – Aerial Photography ...................................... 1-11 Figure 6 Lower Rio Grande Flood Control Project Location........................................................ 1-12 Figure 7 Lower Rio Grande Flood Control Project, Upper River Reach and Main Floodway ..... 1-13 Figure 8 Lower Rio Grande Flood Control Project, Lower River Reach...................................... 1-14 Figure 9 Lower Rio Grande Flood Control Project, North and Arroyo Colorado Floodways....... 1-15

12/26/2007 iii USIBWC

ACRONYMS AND ABBREVIATIONS

ac-ft acre feet ac-ft/yr acre feet per year

ANSI American National Standards Institute

AQCR Air Quality Control Region

ARPA Archaeological Resource Protection Act

CEQ Council on Environmental Quality cfs cubic feet per second

DNL day-night average sound level

E.O. executive order

EOM enhanced operation and maintenance

FCP Flood Control Project

FEMA Federal Emergency Mangement Agency

FM farm-to-market

HCCRD Hudspeth County Conservation and Reclamation District

HPA high probability area

IH Interstate

INS Immigration and Naturalization Service

IWR Integrated Water Resources Management

JTF-6 Joint Task Force - Six

LRGV Lower Rio Grande Valley mg/L milligrams per liter mgd million gallons per day

MPM Multi-purpose project management

MSL mean sea level

MxIBWC Mexico Section International Boundary and Water Commission

NAAQS National Ambient Air Quality Standards

NEPA National Environmental Policy Act

NHPA National Historic Preservation Act

NOI Notice of Intent

NRCS National Resources Conservation Service

NRHP National Register of Historic Places

NWR National Wildlife Refuge

O&M operation and maintenance

PEIS Programmatic Environmental Impact Statement

PM10 particulate matter greater than 10 micrometers

12/26/2007 iv USIBWC

Presidio FCP Presidio-Ojinaga Flood Control Project

RCRA Resource Conservation and Recovery Act

Rectification FCP Rectification Flood Control Project

ROW right of way

SIP state implementation plan

SPCC spill prevention, control, and countermeasures

T&E threatened and endangered

TAC Texas Administrative Code

TARL Texas Archeological Research Laboratory

TPWD Texas Parks and Wildlife Department

TWDB Texas Water Development Board

USACE U.S. Army Corps of Engineers

USBP U.S. Border Patrol

USC U.S. Code

USBR U.S. Bureau of Reclamation

USDA U.S. Department of Agriculture

USEPA U.S. Environmental Protection Agency

USDA U.S. Department of Agriculture

USFWS U.S. Fish and Wildlife Service

USIBWC

United States Section International Boundary and Water Commission

WBC World Birding Center

WMA Wildlife Management Areas

ENGLISH TO METRIC UNITS CONVERSIONS

English Unit Metric Unit multiplier

1 inch 2.54 centimeters

1 foot 0.3 meters

1 mile 1.61 kilometers

1 acre 0.4 hectares

1 ton 907 kilograms

1 acre foot 1,233 cubic meters

1 cubic foot per second (cfs) 0.03 cubic meters per second

1 million gallons per day (gpd) 3.8 million liters per day

1-1 USIBWC

SECTION 1

PURPOSE OF AND NEED FOR ACTION

This section describes the background associated with the action, purpose of and need for the action, the scope of the environmental evaluation, and gives a summary description of each project. Figures illustrating location and main features of flood control projects are presented at the end of Section 1 (Figures 1 to 9).

1.1 BACKGROUND

1.1.1 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 issued regulations to implement NEPA that include provisions for both the content and procedural aspects of the required environmental analysis. In 1978, the Council on Environmental Quality issued regulations implementing the process (40 Code of Federal Regulations 1500-1508).

The United States Section, International Boundary and Water Commission (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). 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.

This Programmatic Environmental Impact Statement (PEIS) evaluates a range of alternatives for maintenance activities and future improvements to three of the USIBWC flood control projects (FCP) located in Texas, along the Rio Grande. Those flood control projects are:

• Rio Grande Rectification Project extending 84.4 miles along the Rio Grande, downstream from American Diversion Dam to Fort Quitman, Texas. For the purposes of this PEIS, this project is identified as Rectification FCP.

• Presidio-Ojinaga Flood Control Project extending over 13.1 river miles of the Rio Grande near Presidio, Texas. Throughout the PEIS this project is abbreviated as Presidio FCP.

• Lower Rio Grande Flood Control Project extending 186 river miles on the Rio Grande, from Peñitas, Texas to the Gulf of Mexico, and including 120 miles of interior floodway. Throughout the PEIS this project is abbreviated as Lower Rio Grande FCP.

1-2 USIBWC

The PEIS evaluates, at a programmatic level, potential environmental consequences that may result from implementation of a No Action Alternative and three Action Alternatives. The following environmental resources are assessed in the PEIS: water resources, biological resources, land use, , cultural resources, socioeconomic resources, environmental health (noise, air quality, environmental hazards) and cumulative impacts.

The PEIS has been prepared by the USIBWC as the lead agency, in cooperation with the U.S. Army Corps of Engineers (USACE) Galveston District, U.S. Bureau of Reclamation (USBR), El Paso Field Office, and U.S. Fish and Wildlife Service (USFWS), Corpus Christi Ecological Services Field Office.

1.1.2 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 (the USIBWC) 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 is 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, as follows:

• 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 lands 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.

1.2 PURPOSE OF AND NEED FOR ACTION

The USIBWC is proposing a range of alternatives for maintenance activities and future improvements to three of its flood control projects located in Texas, along the Rio Grande: the Rectification FCP, Presidio FCP, and Lower Rio Grande FCP. The PEIS is being prepared to evaluate these maintenance improvement alternatives that would allow USIBWC to minimize potential environmental impacts and take advantage of environmental and recreational opportunities while meeting its mandate for flood protection, boundary stabilization, and water delivery.

1-3 USIBWC

Over a 20-year planning period, the USIBWC anticipates the need to improve capabilities or functionality of the Rectification FCP, Presidio FCP and Lower Rio Grande FCP. While some improvements to the flood control projects are already in a planning stage or have been developed at a conceptual level, others represent measures considered feasible but not currently envisioned for implementation. Known or anticipated improvements are typically associated with the projects’ core mission of flood control, boundary stabilization, and water delivery.

Other improvements are associated with additional goals adopted by the USIBWC in support of the projects’ core mission. Those goals include improvements in water use, quality, or conservation, and multipurpose utilization of the projects in support of local or regional initiatives for recreational use or environmental improvement.

In compliance with NEPA requirements, the USIBWC routinely prepares environmental evaluations of proposed actions, typically in the form of an Environmental Assessment or, when warranted by significance of potential effects, an Environmental Impact Statement (EIS).

Because preparation of those environmental evaluations requires specific definition of the proposed action’s characteristics, extent, and location, the USIBWC has taken a broad programmatic look at the potential environmental implications of measures to be considered for future implementation. The PEIS documents the affected environment over an entire flood control project area, and assesses potential environmental consequences.

The USIBWC will apply the programmatic evaluation of potential impacts as an overall guidance for future environmental evaluations of individual improvement projects whose implementation is anticipated or possible within a 20-year timeframe. Once any given improvement project is identified for future implementation, site-specific environmental documentation will be developed based on project specifications and PEIS findings.

For the PEIS evaluation, measures identified as feasible were organized into three action alternatives that reflect the following project goals:

1. Measures associated with the projects’ mission of flood control, boundary stabilization and water delivery, evaluated under the Enhanced Operation and Maintenance (EOM) Alternative;

2. Measures intended to improve water use, quality and conservation, considered under the Integrated Water Resources Management (IWR) Alternative; and

3. Measures in support of local or regional initiatives for increased utilization of the project or to improve environmental conditions, evaluated under the Multipurpose Project Management (MPM) Alternative.

The PEIS compares potential environmental consequences of the EOM, IWR and MPM alternatives with those expected from continued use of current management and operational practices, evaluated under the No Action Alternative.

1-4 USIBWC

1.3 DESCRIPTION OF FLOOD CONTROL PROJECTS

1.3.1 Flood Control Projects Overview

Figure 1 indicates the location of four flood control projects operated by the USIBWC along the United States-Mexico border, three in Texas, along the Rio Grande, and a fourth one in southern California, the Tijuana River Flood Control Project. Rio Grande flood control projects under evaluation in the PEIS are illustrated in Figures 2 to 9 (placed at the end of Section 1), and a comparison of main features of the projects are presented in Table I-1. A brief description is presented below.

Table I-1 Comparison of Key Features of the Rio Grande Flood Control Projects (Sturdivant, et al. 2004)

Lower Rio Grande Flood Control Project Features

Rio Grande Rectification

Project

Presidio- Ojinaga Flood

Control Project River

Segment Interior

Floodways

Flood Information Flood design 100-year 25-year 500 -year 500 -year Freeboard * 2 feet 4 feet 3 feet 3 feet

Design Flow (cubic feet per second)

11,000 cfs at El Paso, TX

3,600 cfs above Rio Conchos

42,000 below Rio Conchos

250,000 cfs at Rio Grande City, TX

105,000 cfs at Anzalduas Dam

20,000 cfs at Brownsville, TX

Floodway (U.S. side, only) Miles of levee 84.5 15.2 102 172

Miles at risk of overtopping 12 1.25 38 2

Miles of insufficient freeboard 38 1.25 64 24

Floodplain Acreage (2004 FEMA Estimates)

Agriculture 2,356 764 75,645

Residential 2,643 320 3,237

Commercial 2,759 0 605

Industrial 32 0 0

Total Acreage 7,790 1,084 79,487

* Freeboard is the levee height above the anticipated water surface levee at design flood conditions

1.3.2 Rio Grande Rectification Project

The Rio Grande Rectification Project, identified in the PEIS as Rectification FCP, was constructed between 1934 and 1938; it extends 86 river miles from El Paso to Fort Quitman, Texas. The purpose of the project is to stabilize the international river boundary and to provide flood protection for both countries in urban, suburban, and agricultural areas. Figures 2 and 3

1-5 USIBWC

show the project location and main geographic features and structures along the upper and lower reaches of the Rectification FCP, respectively.

Prior to the Rectification FCP, instability of the Rio Grande’s channel enabled the river to meander through El Paso, Texas and Ciudad Juarez, Chihuahua. The instability was caused by a combination of heavy sediment loads, a flat gradient, and low river velocities. The Rectification FCP was a bi-national initiative to stabilize the international boundary line between the two countries. The 1933 Convention provided for the creation, operation, and maintenance of an artificial channel whose center line became the new international boundary.

Surveys were undertaken and a rectified river channel established in such a way that the total areas to be “cut” from each country were equal, with the cut areas ceded to the other country.

Costs of the project were pro-rated between the United States and Mexico based on an assessment of relative benefits received from the project. It was estimated that the United States would receive 88 percent of the benefits and Mexico 12 percent; costs were allocated to each country based on these values (Sturdivant, et al. 2004).

The Rectification FCP was constructed by straightening the river channel and developing a narrow floodway by constructing levees on both sides of the river. The channel straightening process removed several meanders and resulted in a reduction in the river length from 155 to 86 miles. Four grade control structures were also installed: Island, Tornillo, Alamo, and Guayuco. The average channel depth along the Rectification FCP is 3 to 5 feet. The width of the channel is between 66 and 100 feet and its capacity is 1,000 cubic feet per second (cfs).

The floodway width averages about 590 feet and its capacity is 11,000 cfs. The project includes 85.4 miles of levees on the U.S. side, and 83.7 miles of levees on the Mexico side.

The average levee height is 7.2 feet, the average top width is 20 feet. The project was designed for the channel to safely contain a 100-year flood event.

1.3.3 Presidio-Ojinaga Flood Control Project

The Presidio FCP was implemented in 1975 to protect productive agricultural lands in the Presidio-Ojinaga Valley from frequent flooding. The project was also intended to establish the international boundary as per the Boundary Treaty of 1970. Figures 4 and 5 show the location of the project and key geographic features.

For many years, insufficient levees resulted in repeated flood damage in the area during the early and mid-1900s. The situation was addressed by ratification of the 1970 Boundary Treaty, which provided for excavation of channels to relocate the Rio Grande in the Presidio Valley.

Subsequent to the Treaty, an IBWC report on flood control (dated June 1971) paved the way for an international agreement of collaborative flood-control efforts in the Presidio-Ojinaga Valley. Based primarily on this report, Title II of Public Law 92-549 (signed October 25, 1972) authorized construction, operation, and maintenance efforts with Mexico for the purpose of providing flood control to the Presidio Valley. The timing of the signing of the international flood-control agreement allowed for 15.2 miles of levee to be built concurrently with the channel relocation (as provided for by the 1970 Boundary Treaty).

The Presidio FCP provided flood protection by augmenting the capacity of the river channel through the construction of cleared berms and levees on both sides of the river. The

1-6 USIBWC

project extends for 13.1 miles through Presidio, Texas. Rectification also took place at the time of project construction, reducing the channel length by about 6.3 miles. Levees on the north and south sides of Cibolo Creek are each 145 feet wide, from the landside limit of the right-of-way (ROW) to the creek side ROW limit. The levees were designed to contain a 25-year flood with 4 feet of freeboard. Downstream of the confluence with the Rio Conchos, the design flow is 42,000 cfs. The levees downstream of the end of the river relocation were raised 4 feet following the September 1978 flood.

There are approximately 15 miles of levee length, including the spur levees. The height of the levees varies from 12 to 35 feet, with the higher at the southern end of the project. The crest width was originally designed to be 16 feet, but is currently between 8 and 12 feet, with the narrower crests at the southern end of the project.

1.3.4 Lower Rio Grande Flood Control Project

The Lower Rio Grande FCP extends approximately 186 miles from Peñitas, Texas to the mouth of the river in the Gulf of Mexico, along Hidalgo, Cameron and Willacy Counties. The project was the result of a 1932 agreement between the United States and Mexico to provide flood protection to urban, suburban, and agricultural lands in both countries. Figure 6 shows the overall project location, and individual maps are provided for the upper river reach of the Lower Rio Grande FCP and the Main Floodway of the interior floodway system (Figure 7), the lower river reach of the Lower Rio Grande FCP (Figure 8), and the other two components of the interior floodway system, the North and Arroyo Colorado Floodways (Figure 9).

The Lower Rio Grande FCP consists of the river channel, flood levees in each country, two diversion dams, and off-river floodways in Mexico and the United States. Some river straightening took place between 1976 an 1977 on a 9,000-foot length of river upstream of Hidalgo and Reynosa. The depth of the river channel varies from 1 to 15 feet.

Two diversion dams, Anzalduas and Retamal, were constructed to route most of the flood flows in the off-river floodway systems of the United States and Mexico, respectively.

Anzalduas Dam also diverts irrigation flows into Mexico. 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 United States portion of the project includes 102 miles of levees along the Rio Grande, and 168 miles in an off-stream, interior floodway system. This off-stream system initiates in the Main Floodway that subsequently separates into the North Floodway and the Arroyo Colorado Floodway at the City of Mercedes. The levee system has an average levee height of approximately 15 feet, 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 project was designed and built for a flood of 250,000 cfs at Rio Grande City. During the design flood, 105,000 cfs would be diverted to the United States’ off-river floodways at Anzalduas Dam, and 105,000 cfs would be diverted to Mexico’s off-river floodway system at Retamal Dam. Diversion of flows at the two dams and water losses between Rio Grande City and the diversions would result in the passage of a maximum of 20,000 cfs through the Brownsville-Matamoros area.

Lower Rio Grande Flood Control Project

Presidio-Ojinaga Flood Control Project

Rio Grande Rectification Project

Tijuana River Flood Control Project (Concurrently evaluated under a separate PEIS)

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Figure 1 Location of USIBWC Projects

Programmatic EIS International Boundary and Water Commission, United States Section¹ 0 100 200 300 400 50050 Miles

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Figure 2 Rio Grande Rectification Project - Upper Reach

Programmatic EIS International Boundary and Water Commission, United States Section¹ 0 2 4 6 81 Miles

0 3 6 9 121.5 Kilometers

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Fi gu re 3 Rio Grande Rectification Project - Lower Reach

Programmatic EIS International Boundary and Water Commission, United States Section¹ 0 2 4 6 81 Miles

0 3 6 9 121.5 Kilometers

Scale = 1: 200,000

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Figure 4 Presidio - Ojinaga Flood Control Project

Programmatic EIS International Boundary and Water Commission, United States Section¹ 0 0.5 1 1.5 20.25 Miles

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Programmatic EIS International Boundary and Water Commission, United States Section¹ 0 0.5 1 1.5 20.25 Miles

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Figure 6 Lower Rio Grande Flood Control Project

Overview Map Programmatic EIS

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Figure 7 LRGFCP Upper River Reach and Main Floodway

Programmatic EIS International Boundary and Water Commission, United States Section¹ 0 2 4 6 81 Miles

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Figure 8 LRGFCP Lower River Reach

Programmatic EIS International Boundary and Water Commission, United States Section¹ 0 2 4 6 81 Miles

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Figure 9 LRGFCP No rt h an d Arroyo Col or ado F lo od wa ys

Programmatic EIS International Boundary and Water Commission, United States Section¹ 0 2 4 6 81 Miles

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2-1 USIBWC

SECTION 2

FORMULATION OF ALTERNATIVES

This section describes how the alternatives were initially identified and processed through the USIBWC, interested stakeholders and government agencies. It further identifies the formulation process to arrive at the alternatives evaluated in the PEIS.

2.1 INITIAL IDENTIFICATION OF POTENTIAL MEASURES

Potential actions and alternatives identified for each flood control project were initially identified by the Engineering, Operations and Environmental Divisions of the USIBWC. A summary description of those actions and alternatives was provided for comment to agencies, state and local governments, organizations, and other potential stakeholders as part of a public scoping process. Findings and conclusions of this process, described in more detail in Section 3.1, were compiled by the USIBWC in the 2005 document Scoping Meeting Summary, Programmatic Environmental Impact Statement, Rio Grande and Tijuana River Flood Control Projects. Comments and recommendations submitted during the scoping process were then incorporated into a revised set of preliminary alternatives for evaluation in the PEIS.

Measures initially identified during PEIS development and scoping meetings were consolidated to reflect four major objectives of the flood control projects:

• Ongoing and future activities associated with the flood control mission of all projects, namely those associated with maintenance and improvements to the levee system and floodways.

• Ongoing and future activities specifically associated with the water deliveries and boundary preservation mission, in accordance with regional and international obligations. Those activities are primarily associated with channel maintenance and sediment removal and management, and apply to the three Rio Grande flood control projects.

• Activities associated with management of water resources such as water quality, use and conservation. While this is not a goal inherently associated with the flood control and water delivery project mission, it reflects strategic goals adopted by the USIBWC as an integral part of improved project functionality and cooperation with local initiatives.

• Activities associated with potential multipurpose use of the projects, such as additional floodway utilization for purposes other than optimization of flood control, as well as regional environmental initiatives outside the USIBWC jurisdiction. These initiatives would be implemented and managed by other agencies or organizations, and supported through cooperative agreements.

Table I-2 presents a summary of potential measures identified for improvement of the Rio Grande flood control projects. Measures are listed according to the main project objectives. Potential applicability of a measure to a given project is also indicated.

2-2 USIBWC

Table I-2. Potential Changes Relative to Current O&M Practices

FLOOD CONTROL PROJECT

Rectification Presidio LRGFCP

FLOOD CONTROL SYSTEM ALONG THE RIO GRANDE

Levee Improvements Levee height increase X X X Structural levee improvements X X X Partial relocation within ROW or new flood easements X

Changes in Floodway Management Changes in vegetation removal and timing/extent of mowing X Restricted Use Zones X

Changes in Channel Maintenance Sediment removal and disposal X X X Shore/aquatic vegetation removal X

INTEGRATED WATER RESOURCES MANAGEMENT

Water Use and Conservation Salt cedar management X X Irrigation BMPs to increase water delivery efficiency X Support maintenance of irrigation structures and drains X

Water Quality Modified irrigation…