J.04_C.1_PEIS_Alternatives_Report_February_26 _2007.pdf

Programmatic Environmental Impact Statement Rio Grande and Tijuana River Flood Control Projects

ALTERNATIVES REPORT

January 2007

PARSONS

Austin, Texas

United States Section International Boundary and

Water Commission El Paso, Texas

ALTERNATIVES REPORT

PROGRAMMATIC ENVIRONMENTAL IMPACT STATEMENT

RIO GRANDE AND TIJUANA RIVER FLOOD CONTROL PROJECTS

Prepared for

UNITED STATES SECTION

INTERNATIONAL BOUNDARY AND WATER COMMISSION

UNITED STATES AND MEXICO

Prepared by:

Parsons

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

USIBWC CONTRACT IBM04D0002, TASK ORDER IBM05T0022

FEBRUARY 2007

Alternatives Report Programmatic Environmental Impact Statement Contents

12/15/2007 i

TABLE OF CONTENTS

SECTION 1 INTRODUCTION.............................................................................................................. 1-1

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

1.2 Report Organization.......................................................................................................... 1-3

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

2.1 Initial Identification of Potential measures and alternatives.............................................. 2-1

2.1.1 Public Scoping ........................................................................................................ 2-1

2.1.2 Measure Organization by Project Objective............................................................ 2-1

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

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

2.2.2 Water Delivery and Boundary Preservation............................................................ 2-3

2.2.3 Project Scale and Diversity ..................................................................................... 2-3

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

2.3 Formulation of Alternatives ............................................................................................... 2-5

2.3.1 Definition of Alternatives by Project Objective ........................................................ 2-5

2.3.2 Mitigation and Compensation Measures................................................................. 2-6

SECTION 3 RIO GRANDE RECTIFICATION PROJECT ................................................................... 3-1

3.1 Description ........................................................................................................................ 3-1

3.1.1 Components ............................................................................................................ 3-1

3.1.2 Water Resources .................................................................................................... 3-1

3.1.3 Environmental Improvements and Initiatives .......................................................... 3-4

3.2 Current Maintenance Practices......................................................................................... 3-4

3.2.1 Levee System.......................................................................................................... 3-4

3.2.2 Floodways ............................................................................................................... 3-4

3.2.3 River Channel.......................................................................................................... 3-5

3.3 Enhanced O&M (EOM) ..................................................................................................... 3-5

3.4 Integrated Water Resources Management (IWR) ............................................................ 3-7

3.5 Multipurpose Project Management (MPM) ....................................................................... 3-8

SECTION 4 PRESIDIO-OJINAGA FLOOD CONTROL PROJECT.................................................... 4-1

4.1 Description ........................................................................................................................ 4-1

4.1.1 Components ............................................................................................................ 4-1

4.1.2 Water Resources .................................................................................................... 4-1

4.2 Current Maintenance Practices......................................................................................... 4-4

4.2.1 Levee System.......................................................................................................... 4-4

4.2.2 Floodways ............................................................................................................... 4-4

4.2.3 River Channel.......................................................................................................... 4-5

4.3 Enhanced O&M (EOM) ..................................................................................................... 4-5

4.4 Integrated Water Resources Management (IWR) ............................................................ 4-7

4.5 Multipurpose Project Management (MPM) ....................................................................... 4-8

12/15/2007 ii

SECTION 5 LOWER RIO GRANDE FLOOD CONTROL PROJECT ................................................. 5-1

5.1 Description ........................................................................................................................ 5-1

5.1.1 Components ............................................................................................................ 5-1

5.1.2 Water Resources .................................................................................................... 5-1

5.1.3 Environmental Improvements/Initiatives ................................................................. 5-6

5.2 Current Maintenance Practices......................................................................................... 5-6

5.2.1 Levee System.......................................................................................................... 5-6

5.2.2 Floodways ............................................................................................................... 5-6

5.2.3 River Channel.......................................................................................................... 5-6

5.2.4 Other Practices........................................................................................................ 5-6

5.3 Enhanced O&M (EOM) ..................................................................................................... 5-6

5.4 Integrated Water Resources Management (IWR) ............................................................ 5-6

5.5 Multipurpose Project Management (MPM) ....................................................................... 5-6

SECTION 6 TIJUANA RIVER PROJECT............................................................................................ 6-6

6.1 Description ........................................................................................................................ 6-6

6.2 Current Maintenance Practices......................................................................................... 6-6

6.3 Enhanced O&M (EOM) ..................................................................................................... 6-6

6.4 Multipurpose Project Management (MPM) ....................................................................... 6-6

12/15/2007 iii

LIST OF TABLES

Table 2.1 Opportunities and Constraints for Project Improvement ................................................. 2-2

Table 2.1 Measure Organization by Categories used in the Formulation of Alternatives ............... 2-6

Table 4.1 Potential Improvements to Flood Control and Water Delivery in the Rectification Project ......................................................................................................... 3-6

Table 4.2 Potential Improvements to Water Resources Management in the Rectification Project ......................................................................................................... 3-7

Table 4.3 Actions Associated with Multipurpose Management of the Rectification Project ............ 3-9

Table 5.1 Potential Improvements to Flood Control and Water Delivery in the Presidio Project .... 4-6

Table 5.2 Potential Improvements to Water Resources Management in the Presidio Project ....... 4-7

Table 5.3 Actions Associated with Multipurpose Management of the Presidio Project................... 4-8

Table 6.1 Potential Improvements to Flood Control and Water Delivery in the LRGFCP............... 5-6

Table 6.2 Potential Improvements to Water Resources Management for the River Reach of the LRGFCP ............................................................................................................... 5-6

Table 6.3 Actions Associated with Multipurpose Management for the River Reach of the LRGFCP ............................................................................................................... 5-6

Table 6.1 Potential Actions Associated with Enhanced O&M and Multipurpose Use of the Tijuana River Project ....................................................................................................... 6-6

LIST OF FIGURES

Figure 1.1 Location of Flood Control Projects .................................................................................. 1-2

Figure 4.1 Upper Reach of the Rectification Project......................................................................... 3-2

Figure 4.2 Lower Reach of the Rectification Project......................................................................... 3-3

Figure 5.1 Presidio-Ojinaga Flood Control Project Location ............................................................ 4-2

Figure 5.2 Presidio-Ojinaga Flood Control Project – Aerial Photography ........................................ 4-3

Figure 6.1 Lower Rio Grande Flood Control Project Location.......................................................... 5-2

Figure 6.2 LRGFCP Upper River Reach and Main Floodway .......................................................... 5-3

Figure 6.3 LRGFCP Lower River Reach .......................................................................................... 5-4

Figure 6.4 LRGFCP North and Arroyo Colorado Floodways............................................................ 5-5

Figure 7.1 Tijuana River Flood Control Project Location.................................................................. 6-6

Programmatic Environmental Impact Statement Introduction

1-1 USIBWC

SECTION 1

INTRODUCTION

1.1 BACKGROUND

The United States Section, International Boundary and Water Commission (USIBWC) is preparing a Programmatic Environmental Impact Statement (PEIS) to evaluate potential impacts of a range of maintenance activities and future improvements to four of its flood control projects. The objective of the PEIS is to evaluate maintenance alternatives and project improvements 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. Those projects, whose locations are illustrated in Figure 1.1, are:

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

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

• 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.

• Tijuana River Flood Control Project in southern California, containing 2.3 miles of levees starting at the international boundary.

In general terms, USIBWC maintains the river channel, floodways, levees, and other structures in the projects; controlling vegetation in the floodways and levees; removing sediment and debris from the channel, floodways, and mouths of arroyos; and grading and stabilizing floodways and levees.

Flood control projects located along the United States portion of the Rio Grande provide boundary stabilization and water delivery in addition to providing flood control to urban, suburban, and agricultural lands. The Tijuana River Flood Control Project in southern California was built only for flood control purposes and does not have the functions of boundary stabilization and water delivery.

This report identifies alternatives developed for maintenance and improvements to the four flood control projects whose potential impacts will be evaluated in the PEIS.

Lower Rio Grande Flood Control Project (Figure 6.1)

Presidio-Ojinaga Flood Control Project (Figure 5.1)

Rio Grande Rectification Project (Figures 4.1 and 4.2)

Tijuana River Flood Control Project (Figure 7.1)

G ulf of California

Paci fic O cean

Gulf of Mexico

El Paso

Texas

Arizona New Mexico

Oklahoma

California

KansasColorado Utah

Arkansas

Nevada Missouri

Louisiana

Sonora

Chihuahua

Durango

Coahuila De Zaragoza

Sinaloa Nuevo Leon

Baja California Sur

Tamaulipas

Zacatecas

Baja California Norte

Rio Grande

Nazas

Conchos

Rio SaladoYa qu i

Ri o

So no ra

Rio Fuerte

Ba vi sp e

Papigochic

M oc te zu m a

Ya qu i

San Lorenzo

RedBrazos

Ri o

G ra nd e

Gila

Pe co s

Arkansas

Canadian

Salt

Colorado

La Paz

Culiacan

Saltillo

Chihuahua

Monterrey

Hermosillo

Tulsa

Austin

Tucson Dallas

Houston

El Paso

Phoenix

Wichita

San Diego

Las Vegas

Fort Worth

San Antonio

Los Angeles

Albuquerque Oklahoma City

Corpus Christi

115°0'0"W

115°0'0"W

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 1.1 Location of USIBWC Projects

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

0 200 400 600 800100 Kilometers

Scale = 1: 6,200,000

Programmatic Environmental Impact Statement Introduction

1-3 USIBWC

1.2 REPORT ORGANIZATION

This report presents the following information:

Section 1: Provides background information on the PEIS objectives.

Section 2: Presents the process followed to formulate the alternatives and an overview of alternatives and actions by control project for evaluation in the PEIS.

Section 3: Describes current maintenance activities and alternatives for improvements in operation and management, water use and conservation, and multipurpose use of the Rio Grande Rectification Project (Rectification Project).

Section 4: Describes current maintenance activities and alternatives for improvements in operation and management, water use and conservation, and multipurpose use of the Presidio-Ojinaga Flood Control Project (Presidio Project).

Section 5: Describes current maintenance activities and alternatives for improvements in operation and management, water use and conservation, and multipurpose use of the Lower Rio Grande Flood Control Project (LRGFCP).

Section 6: Describes current maintenance activities and alternatives for improvements in operation and management and additional uses of the Tijuana River Flood Control Project (Tijuana River Project).

Programmatic Environmental Impact Statement Formulation of Alternatives

2-1 USIBWC

SECTION 2

FORMULATION OF ALTERNATIVES

2.1 INITIAL IDENTIFICATION OF POTENTIAL MEASURES AND ALTERNATIVES

2.1.1 Public Scoping

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. Five public scoping meetings were held in the Cities of El Paso, Presidio, and McAllen, Texas (January 11, 13 and 19, 2005, respectively); Las Cruces, New Mexico (January 12, 2005); and Imperial Beach, California (January 27, 2005). Findings and conclusions of this process 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. The scoping process included a fifth flood control project, the Rio Grande Canalization Project, no longer included in the PEIS evaluation.

2.1.2 Measure Organization by Project Objective

Measures initially identified during development of the PEIS 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.

2-2 USIBWC

• 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.

2.2 BASIS FOR ALTERNATIVES FORMULATION

Feasible and likely beneficial measures were identified on the basis of opportunities and constraints for inclusion in the evaluation of potential impacts. The resulting analysis excluded from evaluation those actions that are in conflict with the project objectives, or small-scale measures with minimum potential impacts or environmental benefit. A summary of key considerations for each individual project is presented in Table 2.1 and briefly discussed below.

Table 2.1 Opportunities and Constraints for Project Improvement Lower Rio Grande (LRGFCP) Opportunities and Constraints Rio Grande

Rectification Presidio- Ojinaga River

Segment Interior

Floodways

Tijuana River

Flood control objective Yes Yes Yes Yes Yes

Primary control of floodway management USIBWC USIBWC

Federal and state natural agencies /

Private / NGOs

USIBWC for use as flood easements

USIBWC

Water delivery and boundary stabilization Yes Yes Yes No No

Dry-weather baseflow Minimum, largely used upstream

Low flow, seasonally variable

Continuous, seasonally variable

Agricultural and municipal return flows

None

Scale 86 miles 13 miles 186 miles 120 miles 2.3 miles Vegetation and wildlife habitat

Relatively diversified

Relatively diversified

Very diversified

Low diversification

Minimum diversification

Environmental issues Limited and mostly known issues

Few and mostly known issues

Complex issues partially addressed

Few and mostly known issues

Few issues associated with the flood control function

Ongoing environmental initiatives for floodway use

Few Few Multiple by agencies and organizations

Small-scale only Few

Potential for additional multipurpose use Moderate Very limited Moderate Very limited Minimum

2.2.1 Flood Control

Flood control is a common element to all projects. The need for improved flood control have been identified for LRGFCP, Rectification Project, and Presidio Project. For the

2-3 USIBWC

LRGFCP, levee improvements are needed, both for the river levee system and interior floodways. Implementation of improvements is underway for upstream reach of the levee system, and others are scheduled for implementation in the downstream reach over the next 3 years. Evaluations of potential levee deficiencies have been completed for the Rectification and Presidio projects. No levee deficiencies have been identified for the Tijuana River Project.

Floodway management is a key component of flood control that restricts extensive vegetation development. Floodways in the Rio Grande Rectification and Presidio Projects are almost entirely under USIBWC management control, providing opportunities for implementation of environmental improvements. Along the LRGFCP reach along the Rio Grande, however, USIBWC jurisdiction is primarily limited to narrow corridors along the streambank and flood control levees; most of the floodway is under private ownership for agricultural use or natural resources management agencies and organizations. Management of the LRGFCP interior floodways, largely used for agriculture, is controlled by the USIBWC as flood easements.

2.2.2 Water Delivery and Boundary Preservation

Water Delivery for irrigation and boundary stabilization are primary functions of the Rectification, Presidio, and river reach of the LRGFCP. These functions are not applicable to the interior floodways of the LRGFCP or the Tijuana River Project.

Rio Grande baseflow conditions during dry weather are largely controlled by water delivery allocations regulated by upstream diversion dams. The USIBWC maintains the river channel and floodways, but does not have control over the timing or extent of irrigation releases.

Rectification Project baseflow below the American diversion dam is minimal throughout the year because flow is largely diverted upstream of the project. A dry stream bed is predominant throughout most of the Rectification Project. The Presidio Project also has low upstream flow contributions, but the baseline flow becomes more stable downstream from a major Mexico tributary stream, the Rio Conchos. Flows reaching the LRGFCP are mainly controlled by operation of the bi-national Falcon Dam and subsequent return irrigation flows.

Baseflow decreases along the project as irrigation water is withdrawn for agriculture. The downstream end of the LRGFCP, below Brownsville, has a minimum baseflow that often causes water ponding and, in recent years, temporary closure of the river mouth into the Gulf of Mexico.

2.2.3 Project Scale and Diversity

Project length and floodway size, as well as topographic diversification, restrict the extent of additional flood control actions or environmental initiatives. The Rectification Project is of a relatively large scale, and topographic and habitat diversification. A steep terrain is predominant in the downstream reach of the project, resulting in a very narrow floodway. The Presidio Project also has a predominantly steep topography and a narrow flooway; its short

2-4 USIBWC

extent and limited floodway provide a low potential for additional flood control or implementation of environmental initiatives. The river segment of the LRGFCP is extensive and is surrounded by a diversified floodway of multi-purpose use; the land located riverside of the levee system is mostly outside USIBWC jurisdiction. Use of the LRGFCP interior floodways is strictly limited to pasture and seasonal agriculture that precludes development of any wooded vegetation or uncontrolled vegetation growth. In the Tijuana River Project, support of environmental initiatives is severily restricted by flood control requirements and small extent of the floodway.

2.2.4 Environmental Initiatives and Cooperative Agreements

Rectification Project

Both flood control needs and Border Patrol operations are primary restrictions to significant vegetation development and implementation of other environmental initiatives along the Rectification Project. Replacement of non-native wooded vegetation with vegetation that has lower water consumption is the most significant and viable regional initiative identified.

During the scoping meetings, focusing on the Rio Bosque Wetlands, located outside the floodway, was proposed as the most effective measure for habitat enhancement because flow in the Rectification Project flows is heavily regulated by upstream control. Other proposed actions for recommended for evaluation included salt cedar management and control, reduced sediment removal, increased sediment control in tributary arroyos, and disposal of dredged channel material outside the floodway.

Presidio Project

Both flood control needs and Border Patrol operations are primary restrictions to significant vegetation development and implementation of other environmental initiatives along the Presidio Project. During the scoping meetings, proposed actions for recommended for evaluation included replacement of non-native wooded vegetation with low-water consumption plant species to be implemented as a regional initiative given the extensive salt cedar infestation upstream of the Presidio Project.

Lower Rio Grande Flood Control Project

Most of the LRGFCP floodplain along the Rio Grande is under private ownership for use in agriculture or, increasingly over the last 20 years, has been acquired by various agencies and organizations for management of natural resources. In the lower 65-mile reach of the LRGFCP, recent regulatory decisions by the USFWS and other agencies have defined the extent of vegetation management, largely restricting potential changes. For the most part, USIBWC participation in environmental initiatives has focused on supporting regional environmental initiatives having flood control or water delivery as a significant component.

Along the LRGFCP interior floodways, a few environmental initiatives have been identified, such as replacement exotic grass species with native species or limited participation in small-scale wetlands development projects.

2-5 USIBWC

The LRGFCP has a steady water flow along most of the stream channel, but its lower reach along the Rio Grande suffers from periodic infestations of water hyacinth and hydrilla that choke the channel. During the PEIS scoping meetings, increased control of these invasive species was recommended. Increased participation of the USIBWC in current and future efforts by other agencies, local governments, and organizations to increased use of the Lower Rio Grande Valley as an eco-tourism destination was suggested to improve the local economy and promote habitat enhancement and recreational opportunities.

Tijuana Project

The specific flood control purpose of the Tijuana Project and its small geographic scale severily limits a significant use of the small floodway for environmental improvement initiatives. The Tijuana Project is located upstream from a valuable protected natural area, the Tijuana River National Estuarine Research Reserve and Tijuana Slough National Wildlife Refuge, providing opportunities for limited USIBWC support of regional environmental initiatives.

2.3 FORMULATION OF ALTERNATIVES

2.3.1 Definition of Alternatives by Project Objective

Measures initially identified during development of the PEIS and scoping meetings were consolidated to reflect four major project objectives previously discussed:

• Ongoing and future activities associated with the flood control mission of all projects;

• Ongoing and future activities specifically associated with the water deliveries and boundary preservation mission;

• Activities associated with management of water resources such as water quality, use and conservation; and

• Activities associated with potential multipurpose use of the projects, implemented and managed by other agencies or organizations, and supported through cooperative agreements.

Those project objectives were used as a guideline for formulation of a No Action Alternative and three action alternatives as described below. Table 2.1 illustrates differences of each alternative relative to the No Action Alternative.

No Action Alternative, the continuation of current O&M practices, including actions planned or identified for short-term implementation.

2-6 USIBWC

Enhanced Operation and Maintenance Alternative (EOM Alternative) addressing anticipated or likely improvements in flood control and water delivery beyond those to be implemented under current O&M practices;

Integrated Water Resources Management Alternative (IWR Alternative) that includes future actions intended to improve water quality, water use and water conservation, in addition to those changes in flood control and water delivery identified under the EOM Alternative;

Multipurpose Project Management Alternative (MPM Alternative) which adds the multi-purpose use of the floodway and environmental initiatives to improvements measures already under consideration under the EOM and IWR Alternatives.

Table 2.1 Measure Organization by Categories used in the Formulation of Alternatives

Measure Category Enhanced

Operation & Maintenance

(EOM)

Integrated Water Resources

Management

(IWR)

Multipurpose Project

Management

(MPM)

IMPROVED FLOOD CONTROL AND WATER DELIVERY

Modifications to levee system X X X Potential for modified floodway management X X X Modified channel maintenance X X X

WATER RESOURCES MANAGEMENT

Improved water use and conservation X X Water quality improvement X X

MULTIPURPOSE PROJECT MANAGEMENT

Additional use of jurisdictional floodway X Cooperative agreements and regional initiatives X

2.3.2 Mitigation and Compensation Measures

In addition to measures previously identified as components of the alternatives, a number of measures have been implemented as mitigation in past projects, either directly by the USIBWC, or developed in cooperation with regulatory agencies and other organizations.

Mitigation measures are not a component of the alternatives and are applicable to any given project or alternative. Mitigation and compensation measures currently implemented or of potential future use include:

• Compensation for extent or quality of impacted wetlands;

• Revegetation in floodways or construction areas;

• Monitoring and improvement of water quality;

2-7 USIBWC

• Site-specific surveys of biological and cultural resources;

• Modified timing or extent of construction or maintenance activities;

• Development or improvement of wildlife habitat corridors;

• Use of in-stream structures to diversify aquatic habitat;

• Off-channel modifications for aquatic habitat development;

• Wildlife habitat improvements outside the jurisdictional ROW such as conservation easements.

Programmatic Environmental Impact Statement Rectification Project

3-1 USIBWC

SECTION 3

RIO GRANDE RECTIFICATION PROJECT

3.1 DESCRIPTION

The Rio Grande Rectification Project, constructed between 1934 and 1938, 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 3.1 and 3.2 show the project location and main geographic features and structures along the upper and lower reaches of the Rectification Project, respectively.

3.1.1 Components

The Rectification Project was constructed by strengthening the river channel and developing a narrow floodway by constructing levees on both sides of the river. The channel strengthening 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 Project is 3 to 5 feet.

The width of the channel is between 66 and 100 feet and its capacity is 1,000 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.

3.1.2 Water Resources

The Rectification Project runs along water quality management Segments 2307 and 2308 of the Rio Grande, as defined by the Texas Commission on Environmental Quality.

Segment 2308 extends from the International Dam to the Riverside Diversion Dam. Flows in Segment 2308 are limited by water diversions upstream at the American and International dams. The designated uses of this segment include limited aquatic life, and non-contact recreation. These designated uses were fully supported according to the 2003 Regional Assessment of Water Quality in the Rio Grande Basin.

Segment 2307 flows 220 river miles from the Riverside Diversion Dam to the confluence with the Rio Conchos, near Presidio, Texas. Flows in Segment 2307 are also minimal and are composed primarily of agricultural and municipal return flows. Designated uses in this segment include contact recreation, public water supply, high aquatic life use, and fish consumption. Water quality information in the Rectification Project portion of the segment indicates that surface water quality standards are exceeded for chloride and fecal coliform. In addition, ammonia levels are above screening limits, which may be the result of either point or non-point pollution.

106°30'0"W

106°0'0"W

106°30'0"W

106°0'0"W

31°30'0"N

31°30'0"N

Figure 3.1 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

Scale = 1: 200,000

Dona Ana County

Otero County

El Paso County Hudspeth County Culberson County

Rio Grande

Chihuahua

MEXICO

Texas

UNITED STATES

New Mexico Juarez

UNITED STATES

Socorro

El Paso

Las Cruces

Figure 4.1 - Upper Reach

Figure 4.2 - Lower Reach

Irrigated Areas

Floodway

Urban Areas

Military Reservation

LEGEND

106°0'0"W

105°30'0"W

31°30'0"N

31°0'0"N

106°0'0"W

105°30'0"W

31°30'0"N

31°0'0"N

Figure 3.2 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

Dona Ana County

Otero County

El Paso County Hudspeth County Culberson County

Rio Grande

Chihuahua

MEXICO

Texas

UNITED STATES

New Mexico Juarez

UNITED STATES

Socorro

El Paso

Las Cruces

Figure 4.1 - Upper Reach

Figure 4.2 - Lower Reach

Irrigated Areas

Floodway

Urban Areas

Military Reservation

3-4 USIBWC

3.1.3 Environmental Improvements and Initiatives

Currently, there are no recreational areas in the floodplain of the Rectification Project. A trail system is under development by the City of El Paso (Rio Grande River Trail and Park) to be operated by the University of Texas at El Paso's Center for Environmental Resource Management. The trail will be located within the U.S. floodplain beginning at Fonseca Drive and extending 4.9 miles to Yarbrough Drive. Outside its ROW, the USIBWC facilitated construction of the Rio Bosque Wetlands Park, a multi-agency project that includes approximately 30 acres of wetlands. Wetlands were constructed as mitigation for a previous USIBWC project, as required in a 1993 Coordination Report by the U.S. Fish and Wildlife Service. Wetlands are supported with effluent from the City of El Paso Bustamante Wastewater Treatment Plant.

3.2 CURRENT MAINTENANCE PRACTICES

3.2.1 Levee System

The USIBWC conducts the following activities for maintenance of the Rectification Project levee system, either routinely or on an as-needed basis:

• Grade and resurface maintenance road on levees

• Mow/cut brush/woody vegetation from levee slopes; repair erosion-related damage

• Maintain grass vegetation

Maintenance of levees includes road maintenance, mowing of slopes, and erosion repairs.

Maintenance supervisors drive the length of the U.S. levees each week to check condition, and repairs are conducted as needed. Resurfacing of levee roads, using gravel, takes place in a 20-year cycle that requires annual improvements at selected locations. Slopes are mowed continually with farm tractors and rotary slope mowers. Approximately 100 river miles of levee slope are mowed annually. Bank stabilization is performed as need or after high flow events, about four to five of which occur per year. Typically after a high flow event, five to six locations are stabilized.

3.2.2 Floodways

The USIBWC conducts the following activities for maintenance of floodways of the Rectification Project, either routinely or on an as-needed basis:

• Mow floodway to control weeds and woody vegetation

• Remove debris in floodway on regular basis

• Perform floodway smoothing to reduce flow resistance

Floodways are leveled annually in areas that need it. Mowing takes place at least twice per year prior to July 15th to remove vegetation and other obstructions from the floodway. Mowing

3-5 USIBWC

is performed along the entire U.S. floodway with farm tractors using rotary slope mowers. The USIBWC also does special vegetation clearing at the request of the U.S. Border Patrol (USBP).

Mowing is not conducted during certain seasons in an area of floodway claimed by the Tiguas, to allow the use of the river for ceremonial purposes, and during Borrowing Owl nesting season. Mowing in this area is conducted at other times of the year. New lighting has recently been installed by the USBP in the floodway from the American Dam to the Zaragoza bridge.

3.2.3 River Channel

The USIBWC conducts the following activities for maintenance of the Rectification Project river channel, either routinely or on an as-needed basis:

• Remove sediment from channel to maintain conveyance capacity and diversion requirements.

• Stabilize banks using riprap revetment and other structural channel linings.

• Perform structural repairs and modifications to dams, bridges, and other structures on an as-needed basis .

• Excavate arroyo mouths to maintain channel grade and conveyance.

• Adjust gates to maintain pool elevation; divert flows and flush sediment and debris

• Maintain grade control structures (Island, Tornillo, Alamo and Guayuco grade control structures).

Riprap revetment is used to stabilize stream banks and to repair scour protection of channel invert at utility crossings. Arroyo mouths as well as the main channel are excavated to maintain channel grade and conveyance and ensure irrigation deliveries. Sediment removal is done on an as-needed-basis. Sediment is deposited at designated locations in the floodway, uplands, federal and private land, as per existing agreements.

3.3 ENHANCED O&M (EOM)

Possible or likely actions for enhanced O&M of the Rectification Project in terms of flood control improvements and changes in water delivery are discussed below and summarized in Table 4.1.

3-6 USIBWC

Table 4.1 Potential Improvements to Flood Control and Water Delivery in the Rectification Project

ALTERNATIVE*

EOM IWR MPM

FLOOD CONTROL AND WATER DELIVERY

Levee Improvements

Levee height increase X X X

Improvement projects required based on hydraulic modeling; most of the improvements are required in the lower reach

Structural levee improvements X X X Changes partially required to implement USACE 2004 recommendations

Relocation within ROW or new flood easements

Changes not anticipated or considered a desirable/viable option for implementation

Changes in Floodway Management Streambank stabilization with vegetation in combination with mechanical means

No significant changes. Small localized projects are possible but not anticipated at a large scale

Vegetation removal and timing/extent of mowing X X X

Changes possible in extent or timing, within current seasonal restrictions

Agricultural/grazing use Use of agricultural/grazing leases for floodway management has been discontinued

Changes in Channel Maintenance

Sediment removal and disposal X X X Changes possible in extent or disposal location (outside floodway under commercial agreements)

Debris removal No changes anticipated; to be continued on an as-needed basis

Shore/aquatic vegetation removal No changes relative to current as-needed basis

New/changes to diversion structures Future construction of structures is not anticipated as an USIBWC initiative

*EOM: Enhanced O&M; IWR: Integrated Water Resources Management; MPM: Multipurpose Project Management

RECTIFICATION PROJECT

Anticipated Change Relative to the No Action Alternative

Improvements to the levee system will entail an increase in height as indicated by the 2003 hydraulic modeling results to meet current flood control criteria. Limited improvements are needed in the upper 45-mile reach of the project (at approximately river miles 0-2 and 15-17);

more extensive improvements have been identified for the lower reach of the project (at approximately river miles 48-52, 59-62, 65-76 and 80-91). Limited structural improvements are also anticipated based on a 2004 study by USACE. Levee relocation along the Rectification Project is not anticipated nor considered a desirable or viable option for implementation by the USIBWC.

Changes in floodway management are possible in terms of timing/extent of mowing and wooded vegetation control. Changes would require compatibility with current seasonal restrictions at some project segments due to ceremonial practices by the Tiguas and nesting season of the Burrowing Owl. Greater restrictions on public use/access to the floodway are expected as a result of increased USBP operations (restricted use zones). Small localized projects of streambank stabilization by bioengineered techniques are possible but not anticipated on a large scale. Leases for agricultural use are not anticipated, and the policy of eliminating grazing leases will be continued (non renewal of existing leases).

3-7 USIBWC

Changes in river channel maintenance would cover primarily sediment disposal outside the floodway through commercial agreements. Timing of sediment flushing from the International Dam could be modified. No changes are expected in the timing or extent of activities for removal of debris and shore/aquatic vegetation, currently conducted on an as-needed basis. Changes to water diversion dams or structures, or new construction, are not planned as USIBWC initiatives.

3.4 INTEGRATED WATER RESOURCES MANAGEMENT (IWR)

In addition to those previously discussed for the EOM Alternative, likely future actions for improvements to water resources management, summarized in Table 4.2, are discussed below.

Table 4.2 Potential Improvements to Water Resources Management in the Rectification Project

ALTERNATIVE*

EOM IWR MPM

FLOOD CONTROL AND WATER DELIVERY

Levee improvements and changes in floodway and channel maintenance X X X

IWR Alternative includes all measures identified as feasible for the EOM Alternative

INTEGRATED WATER RESOURCES MANAGEMENT

Water Use and Conservation

Salt cedar management X X

Changes possible to develop and implement salt cedar management along the channel and arroyos

Revegetation with low-water use species Measure not expected given the very limited vegetation present in the floodway.

Wetlands improvement There are no plans for wetlands development

Support maintenance of irrigation structures and drains

No changes anticipated to ongoing cooperation with irrigation districts

Water Quality

Water quality monitoring No changes anticipated to ongoing participation in state monitoring programs

Modified irrigation drain maintenance X X Possible cooperation plans with irrigation districts to improve return flow quality

Limited floodway revegetation to reduce erosion and sediment load to the river

Implementation not anticipated given the small floodway contribution to watershed sediment load generation

*EOM: Enhanced O&M; IWR: Integrated Water Resources Management; MPM: Multipurpose Project Management

RECTIFICATION PROJECT

Main improvements to water use and conservation are to develop and implement salt cedar management along the channel and at arroyo mouths, a regional priority, as well as revegetation with low-water use species. Another possible improvement is to increase water supply to Rio Bosque Wetlands during the growing season, a measure currently under consideration as a non-USIBWC project. Implementation of irrigation best management practices to increase water delivery efficiency and reduce water losses would be conducted in cooperation with El Paso No. 1 Water Conservation District and Hudspeth County Irrigation District.

3-8 USIBWC

Water quality improvements include continued monitoring to address high chloride and fecal coliform concerns, as well measures to improve water quality in coordination with the two irrigation districts. Those measures include modified irrigation drain maintenance, return flow treatment methods, and maintenance of irrigation structures. Limited floodway revegetation, using grasses, could be implemented in the future to reduce erosion and sediment load in the river.

3.5 MULTIPURPOSE PROJECT MANAGEMENT (MPM)

In addition to those previously discussed for the IWR Alternative, possible actions for multipurpose use of the Rectification Project are discussed below. Those actions are summarized in Table 4.3.

Two potential actions are likely to be implemented in the Rectification Project for multipurpose use of the jurisdictional floodway. First, development of plans for parks, nature trails, and recreational areas proposed by local authorities and/or natural resources management agencies or organizations. These plans will likely be limited to the El Paso vicinity given the increased access restrictions by USBP operations. The second action is the control invasive/exotic species, particularly programs for salt cedar removal, as endorsed by agencies, farming community, and local authorities.

Additional habitat conservation areas and riparian corridors are possible in some relatively undeveloped areas in the lower reach of the Rectification Project; those actions appear feasible only on a small scale due to conflicts with flood control requirements and/or compatibility with USBP operations. Third-party floodway maintenance is not under consideration.

Cooperative Agreements and Environmental Initiatives would extend beyond USIBWC jurisdiction. Those initiatives, to be implemented and managed by other agencies or organizations and supported by the USIBWC under cooperative agreements, may include:

• Participation in salt cedar removal initiatives identified as a regional priority. This action would be conducted in coordination with the Mexican Government as previously implemented by the U.S. Forest Service at the Big Bend National Park.

• Participation in wildlife habitat conservation initiatives identified as regional priorities, including expansion of backwaters at the mouth of arroyos to increase aquatic habitat as an initiative that requires support from both natural resources management organizations and irrigation districts.

• Flow regime modification to provide year-round baseflow. Viable only as a regional, multi-agency initiative; USIBWC has no ownership or direct control of extent or timing of water releases.

• Watershed management for sediment control in support of NRCS and/or regional initiatives.

• Agreements for maintenance of existing dams (Alamo, Camp Rice, Diablo, and Macho Arroyos) and/or development of new dams (Guayuco Arroyo) and sediment traps (Alamo and Diablo Arroyos) for upstream sediment control.

3-9 USIBWC

Two multi-purpose uses of the Rectification Project were excluded from evaluation in the PEIS: reconnection of historic, low-elevation meanders eliminated by the project rectification, now located in private lands; and levee setbacks at flood-prone areas for wildlife habitat expansion, a measure not anticipated or considered feasible for USIBWC implementation.

Table 4.3 Actions Associated with Multipurpose Management of the Rectification Project

ALTERNATIVE*

EOM IWR MPM

FLOOD CONTROL AND WATER DELIVERY

Levee improvements and changes in floodway and channel maintenance X X X

MPM Alternative includes all measures identified as feasible for the EOM Alternative

FLOODWAY AND WATER RESOURCES MANAGEMENT

Improvements in water quality, use and conservation X X

MPM Alternative includes all measures identified as feasible for the IWR Alternative

MULTIPURPOSE PROJECT MANAGEMENT

Jurisdictional Floodway Use

Non-USIBWC floodway maintenance No changes. Third-party floodway maintenance is not under consideration nor anticipated

Parks, nature trails, recreational areas

New initiatives beyond ongoing cooperation with the City of El paso are unlikely given the increased access restriction to the floodway

Control of invasive/exotic species X Implementation possible as part of a regional plan for salt cedar removal

Wildlife habitat conservation No changes are anticipated; existing habitat to be retained as part of the No Action Alternative;

Establish/improve riparian corridors Not viable at a significant extent given flood control requirements and USBP operations

Cooperative Agreements and Regional Initiatives Control of invasive/exotic species outside ROW X

Potential participation in salt cedar removal initiatives identified as a regional priority

Wildlife habitat conservation outside

ROW X

Potential participation as a mitigation action or under a multi-agency habitat conservation initiative

Increase backwaters at mouth of arroyos to increase aquatic habitat

Not viable at a significant extent given minimum water availability

Reconnection of historic, low-elevation meanders to create aquatic habitat

Unlikely implementation due to likely boundary destabilization, losses in water delivey efficiency

Levee setbacks at floodprone areas for increased habitat

Implementation is not anticipated or considered feasible for USIBWC implementation

Flow regime modification to provide year-round baseflow X

Potential participation in a viable regional, multiagency initiative

Watershed management for sediment control

Not significant given the minimum floodway contribution to watershed sediment load.

Upstream sediment control (dams, traps) X

Possible particiaption under interagency agreements (new structures or maintenance of existing structures)

*EOM: Enhanced O&M; IWR: Integrated Water Resources Management; MPM: Multipurpose Project Management

RECTIFICATION PROJECT

Program…