Wastewater Collection Rehabilitation for Main Lines in Tijuana, Mexico Environmental Assessment


Wastewater Collection Rehabilitation for Main Lines

in Tijuana, Mexico

Environmental Assessment







February 4, 2014

U.S. Environmental Protection Agency, Region IX
75 Hawthorne Street
San Francisco, California 94105

Border Environment Cooperation Commission
Comision de Cooperation Ecologica Fronteriza
Blvd. Tomas Fernandez, No. 8069
Cd. Juarez, Chihuahua, Mexico
Telephone: (011-52-16) 25-91-60

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TABLE OF CONTENTS

1.0	INTRODUCTION	2

2.0	PROJECT DESCRIPTION AND ALTERNATIVES	Error! Bookmark not defined.

3.0	AFFECTED ENVIRONMENT	Error! Bookmark not defined.

4.0	ENVIRONMENTAL CONSEQUENCES	18

1

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1.0 INTRODUCTION

The United States Environmental Protection Agency (EPA) administers the Border Environment
Infrastructure Fund (BEIF), which provides grant funding for water and wastewater
infrastructure projects located along the international boundary between the United States (U.S.)
and Mexico. EPA policy for use of border funds requires evaluation and certification of projects
by the Border Environment Cooperation Commission (BECC) as a condition for grant award.
As part of the BECC certification process, the proposed project must comply with (1) Mexican
environmental regulations and (2) the National Environmental Policy Act (NEPA). The EPA
requires compliance with NEPA before BEIF funds can be authorized. Projects within 62 miles
(mi) (100 kilometers [km]) of the U.S./Mexico border are eligible for BEIF assistance.

In accordance with the U.S. Council of Environmental Quality (CEQ) regulations, 40 CFR Parts
1500-1508, and EPA regulations (40 CFR Part 6) as guidance, this Environmental Assessment
(EA) documents the environmental consequences in the U.S. of the proposed federal action. The
purpose of this document is to comply with NEPA documentation requirements for the proposed
federal action under consideration.

1.1 STUDY LOCATION

The proposed project is located in the City of Tijuana, in the state of Baja California in
northwestern Mexico. The City of Tijuana is within the larger municipality of Tijuana, which
has a population of 1,650,351 people, an area of approximately 538 square miles (1,393 square
kilometers), and contains the municipal delegations of San Antonio de los Buenos, Playas de
Tijuana, Centro, Sanchez Taboada, La Mesa de Tijuana, Cerro Colorado, La Presa, Centenario,
and Mesa de Otay.

The City of San Diego is the U.S. city located directly north of Tijuana. San Ysidro is a
community within the City of San Diego located directly on the U.S./Mexico border across from
Tijuana. The City of Tijuana is connected to the San Ysidro district of southern San Diego in the
United States by the San Ysidro and Otay Mesa Border Crossing Stations. The San Ysidro
border crossing is the busiest land-border crossing in the world, with over 50 million people
using the crossing each year.

The area of concern for this EA is relatively flat in the U.S. and hilly in Mexico, generally
ranging from sea level to about 800 feet (245 meters) above mean sea level (amsl) in elevation.
The low-lying parts of the City of Tijuana have an elevation of about 65 feet (20 meters) amsl.

The project area is in the vicinity of the Tijuana River, which originates in the Sierra de Juarez
Mountain Range. The 120 mile (193 kilometer) river flows north through Mexico and into the
United States before draining into the Pacific Ocean. The project collector lines range from
approximately 1,150 feet (350 meters) south of the U.S./Mexico border to 3.4 miles (5.5
kilometers) south of the border.

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1.2 PURPOSE AND NEED

The purpose of the proposed action is to improve the wastewater collection system and sanitary
conditions within the City of Tijuana. The project is needed to address the deteriorated condition
of existing major sewer collector lines and manholes within the City which result in raw sewage
leaks to ground and surface water within the Tijuana River watershed and potentially impacting
the Tijuana River. Thus, on those days when Tijuana River flows reach the U.S., the
implementation of the proposed project would reduce the potential adverse impacts to U.S.
surface water. The proposed project will improve public health and water quality concerns by
eliminating the discharge of raw sewage to Tijuana streets. Public safety concerns will also be
addressed by reducing the risk and potential for collapse of major sewer collectors and manholes
and associated ground subsidence. The lack of reliable wastewater collection lines has had
consequences for the environment of Tijuana, as well as for the quality of life of its inhabitants.
All of the collection lines that are part of the proposed action have shown evidence of damage,
often in the form of leaks and collapses.

1.3 SCOPE OF ANALYSIS

Although the project is located in Mexico, this EA evaluates the impacts to the relevant
environmental resources within the defined area of concern in the U.S. As defined in the CEQ
regulations (§1508.25), the scope consists of the range of actions, alternatives, and impacts to be
considered in a NEPA-compliant document.

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2.0

PROJECT DESCRIPTION AND ALTERNATIVES

In accordance with Council on Environmental Quality (CEQ) regulations (§1502.14), this
section of the EA: 1) presents and objectively evaluates the alternatives, including the No Action
alternative; 2) devotes substantial treatment to each alternative considered in detail so the
reviewers may evaluate comparative merits; and 3) includes appropriate mitigation measures.

2.1 ALTERNATIVES CONSIDERED BUT ELIMINATED FROM FURTHER
STUDY

Alternatives related to stormwater or wastewater treatment were not included in the scope of this
project. Among the range of possible gravity sewer collection projects, alternatives that were not
deemed constructible, such as those that would require extended closures of the City's most
important roads or would be prohibitively expensive, were not considered for detailed study.

2.2 PROPOSED ACTION

The proposed action would rehabilitate or replace 5.5 miles (8.9 kilometers) of collector lines
with diameters ranging from 8 to 42 inches (20 to 107 centimeters) and rehabilitate
approximately 37 manholes and construct an additional 10. The proposed project would occur on
Tijuana's Industrial Collector, Las Americas Collector, Techite Collector, Sanchez Taboada
Collector and Articulo 123 Collector. The first four collectors discharge to the South Bay
International Wastewater Treatment Plant (SBIWTP) or the San Antonio de los Buenos
Wastewater Treatment Plant (WWTP), depending on the volume of sewage within the Tijuana
wastewater collection system. The fifth collector discharges to the San Antonio de los Buenos
WWTP.

2.3 EXISTING INFRASTRUCTURE

The Comision Estatal de Servicios Publicos de Tijuana or CESPT is the utility in Tijuana that
operates the water and wastewater systems for Tijuana and Playas de Rosarito. Essentially all
residents and businesses in the project area, which is in the central part of Tijuana, are connected
to the sewer collection system. Within the Tijuana municipality as a whole, wastewater
collection service coverage is 90 percent (BECC 2012).

In the project area, wastewater from the collection system flows by gravity to two large collector
lines that run parallel to the Tijuana River, one on each side. The Poniente (West) Collector
conducts wastewater from the western side of the City and the Oriente (East) Collector conducts
wastewater from the eastern side of the City. Both the Oriente and Poniente collectors empty to
the Internacional Interceptor, which brings the wastewater to treatment facilities.

Figure 1-1 in Section 1 contains an overview of the existing pumping and treatment
infrastructure.

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5

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Figure 2-1 shows the five collector lines that are part of the proposed action.

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03A V

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ARTICULO 123
COLLECTOR

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Figure No. 2-1
Ovorvisw af fhn Proposed Adion

November 2Q13

6

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There are four existing wastewater treatment plants that treat wastewater from within the Tijuana
River Watershed: the San Antonio de los Buenos WWTP, the South Bay International
Wastewater Treatment Plant (SBIWTP), the La Morita WWTP, and the Arturo Herrera WWTP.

The San Antonio De Los Buenos plant has capacity to treat up to 25 MGD (1,100 L/s) of Tijuana
and Playas de Rosarito wastewater. Based on data from January through October, the CESPT
projects that the plant will treat an average of 25.3 MGD (1,110 L/s) in 2013. The plant is
located 4.3 miles (7 km) south of the border and discharges effluent into the Pacific Ocean at
Punta Bandera. When the capacity of the existing WWTP is exceeded, the plant discharges a
combination of treated wastewater and chlorinated-only wastewater. It has been suggested that
the coastal currents in the region sometimes move from south to north, creating the possibility
that discharges from the San Antonio de Los Buenos Wastewater Treatment Plant may
occasionally affect the quality of the water along the coastal U.S.

The SBIWTP is in San Ysidro, California at the U.S./Mexico border, and treats wastewater
generated exclusively in Tijuana. The SBIWTP provides secondary treatment with a capacity of
25 MGD (1,100 L/s) and discharges effluent through an underwater outfall pipe (the South Bay
Ocean Outfall (SBOO)) into the Pacific Ocean. The SBOO extends 3.5 miles into the ocean and
has a tunnel 11 feet in diameter, and a capacity of 175 MGD (7,623 L/s) which helps to dilute
effluent entering the ocean and to reduce environmental impacts. SBIWTP discharges are subject
to California water quality standards and are specified in the National Pollution Discharge
Elimination System (NPDES) permit for the plant. The SBIWTP treats an average of 25 MGD
(1,100 L/s).

The La Morita WWTP, with a design capacity of 5.8 MGD (254 L/s) provides advanced
secondary treatment using an oxidation ditch activated sludge treatment process followed by
filtration and UV disinfection. Based on data from January through October, the CESPT projects
that the plant will treat an average of 4.5 MGD (199 L/s) in 2013. The WWTP is located
approximately 6.5 miles (10 km) south of the border and 2.9 miles (4.7 km) east of the Arturo
Herrera WWTP. The plant discharges to the Tijuana River via the Matanuco Creek.

The Arturo Herrera WWTP has a design treatment capacity of 10.5 MGD (460 L/s). This plant,
also located within the Tijuana River basin, provides advanced secondary treatment similar to La
Morita and has two modules of 5.25 MGD (230 L/s) each. Based on data from January through
October, the CESPT projects that the plant will treat an average of 5.7 MGD (248 L/s) in 2013.
The WWTP is located approximately 6.5 miles (10 km) south of the border. It also discharges to
the Tijuana River.

Flows in the Tijuana River (which are a combination of groundwater, natural runoff, treated
wastewater effluent, potable water leaks, sewer leaks and spills) are intercepted at the border
before crossing into the U.S by the CILA pump station. From the CILA pump station, flows are
directed to the Internacional interceptor and combined with sewage flows from the Tijuana
wastewater collection system. Approximately 25 MGD (1,100 L/s) of the flow conveyed by the
Internacional Interceptor runs by gravity to the SBIWTP and the rest continues to Pump Station
1 where it is pumped to the San Antonio de los Buenos WWTP. The CILA pump station
currently removes up to 22.8 MGD (1,000 L/s) of river flows and stops operating in wet weather

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when river flows exceed that capacity. At these times, water is allowed to flow into the U.S.,
discharging to the Pacific Ocean via the Tijuana River estuary.

Construction has recently been completed on the Sistema de Alejamiento de Aguas Superficiales
(SAAS), a new surface water removal system that is projected to be placed into operation within
the year. The new system, which includes pumping capacity at the CILA Pump Station, the new
Pump Station 1A, force mains, and gravity mains, will intercept at least 34.2 mgd (1,500 L/s) of
water from the Tijuana River at the CILA pump station and send it, via Pump Station 1 A, to the
Pacific Ocean at Punta Bandera. The water in the SAAS system will not mix with untreated
wastewater or pass through a wastewater treatment plant. The system will provide chlorination at
the ocean discharge only when needed. Operation of the SAAS system will relieve the extra
burden of river water that is currently affecting the wastewater pumping, conveyance, and
treatment infrastructure in Tijuana, and will reduce the number of instances of hydraulic capacity
exceedance at the San Antonio de los Buenos WWTP.

2.4 ALTERNATIVE 1 - NO ACTION ALTERNATIVE

Under the no action alternative, no sewer collector line repair or rehabilitation would take place.
The Industrial, Las Americas, Techite, Sanchez Taboada, and the Articulo 123 Collectors would
continue to be used in their current states, with repairs occurring only following major incidents
such as collapses. Figure 2-1 shows the locations of these five collector lines.

Current conditions include:

• Higher than normal rainwater infiltration, which can cause can cause backups or
excessive water being delivered to the WWTP.

• The escape of wastewater to the open air and undermining and sinking of the street in
areas of heavy truck traffic.

• Leaks to the ground and surface water in the Tijuana River watershed.

• Collapse and deterioration of the concrete and iron structures of the manholes allowing
odors to escape.

• Deteriorated concrete piping material with aggregate materials and bar wrapping

• exposed.

• Blockages of the collector lines.

2.5 ALTERNATIVE 2 - PREFERRED ALTERNATIVE

The preferred alternative would either rehabilitate or replace five main collector lines, over a
total length of 5.5 miles (8.9 kilometers) ranging in diameter from 8 to 42 inches (20 to 107
centimeters). The alternative also includes the rehabilitation of approximately 37 manholes and
the construction of 10 new manholes.

The inspection of the Industrial Collector showed the existing collector in a weakened and
deflected condition, making it a poor candidate for cleaning, especially with the heavy truck
traffic that the road receives. Replacement within the road is proposed, using pipe bursting on
the majority of the length, with open cut replacement in some segments. Two new manholes are
anticipated to be added where the collector length between manholes is more than 377 feet (115
meters). If hidden manholes are discovered, they will be brought to grade, and if badly
deteriorated manholes are discovered, they will be rehabilitated.

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During construction, wastewater flows in the collector would be redirected to one of the smaller
parallel lines that flows to the Oriente Collector as part of the wastewater collection grid. No
wastewater would be sent to the storm sewers.

In the Lomas de Agua Caliente neighborhood, the Las Americas Collector would be replaced by
pipe bursting, with a small contributing line replaced using open cut. In the 20 de Noviembre
neighborhood, the existing concrete Las Americas Collector line would be replaced by open cut
with PVC. In the Buena Vista neighborhood, the Las Americas Collector would be replaced by
pipe bursting, while two other connecting sewer lines would be replaced, one by open cut and
one by pipe bursting.

Wastewater that would normally flow to the project collectors during construction in Lomas de
Agua Caliente would be sent to a storm sewer that would flow to the Tijuana River Canal, would
combine with river water, and would be captured by the SAAS system. The SAAS system
normally discharges to the Pacific Ocean at Punta Bandera, but to avoid any raw wastewater
discharges to the ocean during construction, the water in the SAAS system would be diverted to
the San Antonio de Los Buenos WWTP. The diversion and treatment of the water in the SAAS
system at the WWTP would continue throughout the duration of the construction in the Lomas
de Agua Caliente neighborhood. In 20 de Noviembre and Buena Vista, wastewater needing to be
diverted during construction would be sent to other wastewater lines draining to either the
Poneiente or Oriente Collectors.

The Techite twin collector lines run down the wide median of the busy and economically vital
boulevard, Paseo de los Heroes. It is proposed that 10 new manholes be constructed and 12
existing manholes be rehabilitated along this line. Any design must consider the importance of
keeping traffic flow open on the road and the park-like line of mature trees in the median. During
the tie-ins, wastewater would be diverted out of the Techite twin collectors and to other lines
leading to the Poniente Collector.

The Sanchez Taboada Collector line would be replaced in the adjacent street using open cut
construction and a combination of PVC pipe with either fiberglass reinforced plastic (FRP) or
high density polyethylene (HDPE). The existing line would continue to operate during
construction. During the tie-in to the new line wastewater in the collector would be diverted to a
storm sewer. The wastewater in the storm sewer would flow to the Tijuana River Canal, where it
would be sent to the San Antonio de los Buenos WWTP via the SAAS system.

In the area designated for Phase 2, the Sanchez Taboada Collector follows the busy Sanchez
Taboada boulevard. Both pipe bursting and open cut methods would be used during this phase.
Manholes would be rehabilitated for the entire length of Phase 2 work. When wastewater
diversions were necessary, the wastewater would be diverted to storm sewers that would direct
the wastewater to the Tijuana River Canal, to be treated at the San Antonio de los Buenos
WWTP via the SAAS system.

The Articulo 123 Collector, also called the INV Collector is located under the narrow, residential,
winding, Articulo 123 road, part of which is paved and part of which is unpaved. Rehabilitation
would be primarily by pipe bursting with some small segments of open cut construction.

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Wastewater that would normally flow to the project collector during construction would be
diverted, using plugs and sump pumps when necessary, to other lines within the wastewater
collection grid.

10

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3.0 AFFECTED ENVIRONMENT

This section describes the environmental resources in the U.S. that may be affected by the
proposed action or the no action alternative described in Section 2. The description of the
environmental setting focuses on environmental resources located within the U.S. near the U.S.-
Mexico border. However, environmental resources in Mexico are also described in some
instances when there is a direct correlation between resources in both countries.

3.1 LAND USE

Urban development extends north from the City of Tijuana to the border. The environmental
setting in the vicinity of the border in the U.S. is characterized by a combination of urban,
industrial, rural and open space land uses. Important features of this area include the Pacific
Ocean, the Tijuana River Valley, and the community of San Ysidro, the main urban border
community in the U.S. within the study area.

Important land uses in the Tijuana River Valley are the Tijuana River National Estuarine
Research Reserve (TRNERR), the Imperial Beach Naval Air Station, the Border Field State Park
and the San Diego County Tijuana River Valley Regional Park. The Tijuana River Estuary is
designated by the National Park Service as a National Natural Landmark (NPS 2013).

The Mexican Federal government has designated 173 Natural Protected Areas in Mexico. The
closest Natural Protected Area in Mexico to the area of concern is the Constitucion de 1857,
approximately 70 miles (113 km) southeast of Tijuana (Comision Nacional de Areas Naturales
Protegidas 2007). Located in the pine forests of Sierra de Juarez mountain range, the park is an
important preserve for a large number of native wild animals like Bighorn Sheep and Mule Deer.
The park is characterized by the large variety of coniferous species.

Important farmland including areas of prime farmland, farmland of statewide importance, and
farmland of local importance are located in and around the Tijuana River Estuary, to the west of
U.S. Interstate 5 and south of Imperial Beach (State of California Department of Conservation
2012).

The coastal zone boundaries extend west from the point where the Tijuana River enters the U.S
to the Pacific Ocean, which includes the entire Area of Concern in the U.S. Per the California
coastal Act of 1976, any development activities within the coastal zone boundary must be
approved by either the Coastal Commission or the local government.

3.2 TOPOGRAPHY AND SOILS

Topographic features include the relatively flat alluvial plain of the Tijuana River with tributary
canyons and hillsides extending up into Mexico. The elevations in the study area range from sea
level at the Pacific Ocean, to 100 feet (30 m) in the Tijuana River Canal in Mexico, to nearly 800
feet (244 m) at the highest of the sewer collector lines described in Section 2.

The mudflats at the mouth and lower parts of the Tijuana River Estuary are occasionally covered
by sands transported during storms from the beach Saline Chino. The soils suitable for
agriculture occur upstream from the flats. To the south, the fine sandy loams blanketing the

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mesas and terraces are also considered highly erodible and are contributing substantially to
downstream sedimentation (TRNERR 2010).

3.3 WATER RESOURCES
3.3.1 Surface Water

The two most important surface water features in the area of concern are the Tijuana River and
the Pacific Ocean. The Tijuana River originates at the confluence of Arroyo del Alamar and Rio
de las Palmas in Mexico and drains into the Pacific Ocean. The Tijuana River watershed is
1,700 square miles with 73 percent in Mexico (TRNERR 2012). Flows in the river consist
typically of a combination of natural runoff, effluent discharges, and fugitive flow resulting from
water and wastewater leaks.

Mexico has agreed to intercept the flow of the Tijuana River during the dry season for its
transport to the SBIWTP and the San Antonio de los Buenos WWTP for treatment and disposal.
During the rainy season, however, the Tijuana River flow is allowed to continue into the U.S.
and to discharge into the estuary whenever the flow exceeds 22.8 MGD (1,000 L/s). Flow
records from the U.S. International Boundary and Water Commission (USIBWC) show that in
2008 and 2009, the two most recent years for which the data are available, there were 111 and
116 days, respectively, on which surface water flowed from Mexico to the U.S. These days
occurred mostly during the typically rainy season of December through March.

A 2009-2010 study of water quality in the Tijuana River suggests that raw wastewater discharge
is the likely source of much of the river's impairment (Weston Solutions 2011).

Table 3-2 lists water quality data in the Tijuana River during a random dry weather sampling on
discrete dates in 2009 and 2010. Measurements were taken at a multi-sector general permit site,
MS4D-TJR-07 near the mouth of the Tijuana River.

Table 3-2 Water Quality Measurements in the Tijuana River during Dry and Wet Weather

Enterococcus

(MPN/

100ml)

TSS
(mg/L)

TDS

(mg/L)

Nitrite
as N
(mg/1)

Total

Phosphorus
(mg/L)

Fecal

Coliform

(MPN/lOOmL)

Ammonia

as N
(mg/1)

Dry
Weather

03/17/2010

500,000

2,150

720

<0.05

14.619

9,000,000

16.4

Assessment

05/11/2010

1,300,000

710

1,200

<0,15

5,000,000

Wet
Weather

11/28/2009

>16,000,000

5,717.5

560

0.56

15.893

5,000,000

8.4

Assessment

02/06/2010

2,400,000

2,630

1/770B

<0.75

13.745

5,000,000

14.83

B-Analyte was detected in the associated method blank.
Source: Weston Solutions 2011

Table 3-3 shows the California Basin Plan standards for water quality constituents of concern.
Tijuana River flows shown in Table 3-2 do not meet these standards.

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Table 3-3 California Basin Plan Standards

Parameter CA Basin Plan Standards1

0.025 mg/1 in inland surface waters and
Ammonia (NH3)(mg/L) estuaries

Phosphorus (total) (mg/L) 0.1 mg/L

Nitrite (as nitrogen) (mg/L) 1.0 mg/L

Fecal Coliform(MPN/100mL) 200/100 mL (30-day period, five samples)

'Source: California Regional Water Quality Control Board

http://www.waterboards.ca.gov/sandiego/water issues/programs/basin plan/docs/update082812/Chpt 3 2012.pdf

Ocean water quality in the vicinity of the international border is affected by surface runoff that
flows to the ocean and by discharges from wastewater plants. The San Antonio de los Buenos
WWTP, located approximately 4.3 miles (7 km) south of the border, discharges a combination of
treated wastewater and chlorinated raw wastewater directly in the ocean. It has been suggested
that the coastal currents in the region occasionally move from south to north, creating the
possibility that some discharges from the San Antonio de los Buenos WWTP affect the quality of
the water in the San Diego Bay in the United States.

The SBIWTP is located in San Diego and treats wastewater from Tijuana at a secondary level.
The SBIWTP discharges into the bay through an underwater outfall pipe (i.e., the South Bay
Ocean Outfall - SBOO), which helps to dilute effluent entering the ocean and to reduce
environmental impacts.

The City of San Diego performs monthly compliance monitoring for the SBOO. The sampling
area extends from the tip of Point Loma, California southward to Playa Blanca, Baja California,
Mexico, and from the shoreline seaward to a depth of 200 ft (61 m). There was no evidence that
the wastewater plume from the South Bay outfall reached recreational waters in 2012.

3.3.2 Groundwater

Groundwater in the lower Tijuana River Valley occurs in the following three zones: (1) beneath
Nestor Terrace north of the valley, (2) in the alluvial fill underlying the Tijuana River valley, and
(3) in the San Diego Formation beneath the alluvium. The primary source of aquifer recharge
appears to be the Alamar River. Other likely sources of recharge are winter rainfall, water line
leakage in Tijuana, and discharge from surrounding sedimentary bedrock terraces. Recharge to
the alluvial aquifer from the Tijuana River surface flow is more prominent in the U.S. than
Mexico, since the Tijuana River is a concrete lined channel from the international border to
Rodriguez reservoir. The primary aquifer discharge zone is the Pacific Ocean (BECC 2008).

There is currently no known extraction of groundwater from the Tijuana River basin in the U.S.
for any purpose except for limited agricultural use. As of 1993, groundwater extraction in the
Tijuana River valley north of the international border was 1,400 acre feet per year (BECC 2008).

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Groundwater in the basin is rated generally inferior for domestic use and inferior for irrigation
purposes. High levels of total dissolved solids and sodium chloride prevent the use of
groundwater for salt-sensitive crops (BECC 2008).

3.3.3	Floodplains

The Tijuana River transitions from a natural river bed, south of Tijuana, to a concrete lined canal
designed to hold floodwaters, as the river passes through the highly urbanized City of Tijuana.

Downstream of the border, the U.S. IBWC operates the Tijuana River Flood Control Project,
which extends for 2.3 miles (3.7 km) (IBWC 2005). Downstream of the IBWC flood control
project, the Tijuana River valley in the U.S. consists of a broad natural floodplain containing a
variety of wetland and riparian areas. A wide swath of the Tijuana River valley in the U.S. is in
the 100-year floodplain. A 100-year flood has a 1 percent chance of occurring in any given year.

3.3.4	Wetlands

The 2,800 acre TRNERR was designated as a wetland of international importance within the
nation. It extends east from where the Tijuana River meets the Pacific Ocean and encompasses
tidally flushed wetlands, riparian and upland habitats extending immediately north of the U.S.
and Mexico border (City of San Diego 2007). The closest key wetland in Mexico to Tijuana
identified by Ducks Unlimited de Mexico is a palustrine emergent wetland measuring 4,675
acres (1,892 hectares) located approximately 127 miles (205 kilometers) to the southeast of
Tijuana.

3.4 AIR RESOURCES

The San Diego Air Basin (SDAB) would, in general, be the area of influence for this project.
The climate in San Diego County is typical of a Mediterranean climate. In general, most rains
fall from January to March. Average temperatures reach annual lows of 46°'F (8°C) in winter
and rise to 74°F (23°C) in summer. aPrevailing winds come from the northwest in winter and
from the southwest in summer. Weather is monitored at the TNERR as part of the NERR
System-Wide Monitoring Program (SWMP) (TRNERR 2010).

3.4.1 Air Quality

The federal Clean Air Act (CAA) of 1970 and the CAA Amendment in 1977 required the
adoption of national ambient air quality standards (NAAQS) for sulfur dioxide (SO2), carbon
monoxide (CO), nitrogen dioxide (NO2), hydrocarbons (HC), ozone (O3), particulates of less
than 10 microns in size (PM-10) and lead (Pb). In addition, the California Air Resources Board
(CARB) has established state standards that are generally more restrictive than the national
ambient air quality standards (NAAQS), and include sulfates, hydrogen sulfide (H2S), vinyl
chloride, and visibility reducing particles.

Table 3-1 shows the annual number of days that pollutants exceeded the state and federal
ambient air quality standards in the SDAB during 2008 to 2012.

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Table 3-1 Summary of Air Quality Data for the San Diego Air Basin

Number of Days over Standard
2008 2009 2010 2011 2012

Ozone

FederalA

35

24

14

10

10

(8-Hour Standard)

State

69

47

21

33

25

Particulates

Federal

6.1

0

0

0

0*

(PM10)

State

163.4

146.4

136

138.5

6.1

Particulates

Federal

3.5

3.4

2.0

3.0

1.0

(PM2.5)













Source: http://www.arb.ca.gov/adam/
insufficient Data Available
A National '08 8-Hour

The SDAB currently has a federal and state ozone designation of nonattainment (CARB 2012).
The SDAB is listed as unclassified with the federal standards for PM-10, and
unclassified/attainment for PM-2.5, but is currently listed in non-attainment status for both with
the state standards (CARB 2012).

3.4.2 Odor

Odors have been reported in the vicinity of the Techite and Sanchez Taboada collector lines and
are thought to be due to H2S production resulting from inadequate maintenance, caused by the
wide spacing between manholes. These odors are localized and do not affect the area of concern
in the U.S.

3.5	NOISE

The area of concern with respect to noise is limited to those areas in the U.S. that are
immediately adjacent to the international boundary.

Due to the highly urbanized nature of Tijuana and the area of concern immediately near the
international border on both sides, the area of concern is characterized primarily by vehicular
noise from car and truck travel, commercial aircraft noise from operations at the Tijuana Airport,
aircraft operations associated with Brown Field and the Imperial Beach Naval Auxiliary Landing
Field, and general urban activities.

3.6	VEGETATIVE HABITAT

San Diego County falls under the Southern and Central California Chaparral and Oak
Woodlands ecoregion. This region is characterized as having a Mediterranean climate of hot dry
summers and cool moist winters, and associated vegetative cover comprising mainly chaparral
and oak woodlands with grasslands occurring in some lower elevations and patches of pine being
found at higher elevations (EPA 2013).

Habitat types within the Tijuana River Valley and Tijuana Estuary include beach, saltpan,
southern foredunes, tidal estuary, coastal salt marsh, riparian wetlands, coastal sage scrub,
southern maritime chaparral, maritime succulent scrub, southern willow scrub, and mulefat scrub
(USffiWC 2005).

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For the most part, the portion of the River Valley located between the international border and
Dairy Mart Road is devoid of notable biological resources while areas west of Dairy Mart Road
and north of Monument Road support a variety of bird species and are high in habitat value. The
subject area is interspersed with agricultural, equestrian, mining, and rural residential uses, but,
overall, is still rich in wildlife values. The most notable area of biological resources is the
Tijuana Estuary, which extends approximately 3 miles east from the Pacific Ocean (BECC
2008). The Tijuana Estuary is an essential breeding, feeding, and nesting ground for over 370
bird species (California Department of Parks and Recreation 2013).

The Tijuana Estuary is classified as a Coastal Plain Estuary with several different habitats
occuring within the Estuary (BECC 2008).

3.7 WILDLIFE RESOURCES

The Tijuana River estuary is home to at least 370 species of birds, 320 of which are migratory.
Mammals that inhabit the estuary land include mice, California ground squirrels
(Otospermophilus beecheyi) and rabbits. The estuary's small tidal creeks and channels contain at
least 20 species of fish, plus crabs, rove beetles (Staphylinus sp.), tiger beetles (Cicindela sp.),
and wandering skippers (Panoquina errans) (IBWC 2005).

3.7.1 Threatened and Endangered

The U.S. Fish and Wildlife Service has listed 44 threatened or endangered species as having the
potential to occur in San Diego County. Federally listed endangered and sensitive species may
be found in the general vicinity of the estuary where suitable habitat is present (IBWC 2005).

3.8 CULTURAL RESOURCES AND AESTHETICS

There are no Native American reservations in the area of concern in the U.S. (EPA, 2011).
There are 208 locations in San Diego County listed on the National Register of Historic Places,
California State Historical Landmark, California Register of Historical Resources or as a Point of
Historical Interest (OHP, 2013).

3.9 SOCIOECONOMICS AND ENVIRONMENTAL JUSTICE

The racial composition of the City of San Diego and the State of California are both
predominantly white with the City of San Diego boasting a lower unemployment rate and a 0.2
percent higher poverty rate. San Diego County is projected to grow at a slower rate than the
State of California through 2050.

3.10 MUNICIPAL SERVICES
3.10.1 Water and Wastewater Services

The CESPT provides water and sewer service for Tijuana and Playas de Rosarito. Essentially all
residents and businesses in the project area are connected to the water distribution and
wastewater collection systems (BECC 2012).

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3.10.2	Waste Management

Solid waste collection is provided by the Municipality with a coverage rate of 83 percent in the
Municipality as a whole and 93 percent in the urban center (Ayuntamiento de Tijuana 2010).
Solid waste is sent to two private landfills, in Tijuana and Playas de Rosarito, operated by the
company GEN Tijuana.

3.10.3	Transportation

The District of San Ysidro's location on the US/Mexico border allows events in Tijuana to
potentially influence conditions in Mexico, and vice versa. The distance from the center of San
Ysidro to downtown Tijuana is only about 2.85 miles (4.59 kilometers). As the busiest land port
of entry in the western hemisphere, the San Ysidro Land Port of Entry processes 50,000
northbound vehicles and 25,000 northbound pedestrians each day (U.S. General Services
Administration 2013).

3.10.4	Energy

Ninety nine percent of residents of the Tijuana municipality have access to electricity (SEGOB
2010). Electricity is provided by the Federal government through the Comisidn Federal de
Electricidad throughout Mexico.

3.11 HUMAN HEALTH AND SAFETY

Current health concerns are associated with discharges of raw or inadequate sewage collection in
neighborhoods in Tijuana.

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4.0 ENVIRONMENTAL CONSEQUENCES

Potential impacts are described for each of the alternatives considered. Not all the resource areas
are discussed in Section 4.0. Areas where no impacts would occur have not been analyzed. For
the resource areas where effects will occur, the different types of effects (e.g. beneficial, adverse)
are identified for each resource (e.g. air, water). Furthermore, cumulative impacts and
irreversible commitment of resources for each alternative are described.

The description of impacts is focused specifically on impacts to U.S. resources, but may contain
descriptions of impacts in the entire Area of Concern, which encompasses the City of Tijuana,
the community of San Ysidro, the Tijuana River from Tijuana to the Pacific Ocean, the sites of
proposed wastewater collection improvements, the existing wastewater treatment plants, and
effluent discharge locations.

Under the no action alternative (Alternative 1), rehabilitation and/or replacement of the main
collector lines and existing manholes would not occur and the use of the existing infrastructure
would continue. Alternative 2 seeks to either rehabilitate or replace five main collector lines, a
total length of 5.5 miles (8.9 kilometers) ranging in diameter from 8 to 42 inches (20 to 107
centimeters). The alternative also includes the rehabilitation of approximately 37 manholes and
the construction of 10 new manholes.

4.1 LAND USE

Under the no action alternative, rehabilitation and/or replacement of the main collector lines and
existing manholes would not occur and the use of the existing infrastructure would continue.
The no action alternative would not affect land, use since no construction would take place.

There would be no transboundary effects on land use for Alternative 2. All construction would
take place in existing streets and right-of-ways in Mexico. No construction would take place that
would affect important farmland or coastal zones.

4.2 SOILS AND TOPOGRAPHY

Under the no action alternative, adverse impacts to soil from raw sewage and spillovers from
failing collector lines would continue since no rehabilitation and/or replacement of the main
collector lines and existing mainholes would occur.

The proposed action would address the adverse impacts to soil of raw sewage from the aging
collection line system. During construction, standard measures will be in place to control
erosion and dust.

4.3 WATER RESOURCES
4.3.1 Surface Water

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Tijuana River flows into the U.S., there potentially could be adverse impacts to water quality on
the U.S.-side from contamination of the river water from raw sewage.

With the proposed action, surface water quality within the Tijuana River will improve since there
will be a reduction in raw sewage leaks from failing collector lines within the Tijuana
wastewater collection system. Thus, on those days when Tijuana River flows into the U.S., the
potential adverse impact to U.S. surface water would also be reduced.

During construction, wastewater flows would be diverted to unaffected collection lines within
the Tijuana wastewater collection system.

4.3.2 Groundwater

Under the no action alternative, intermittent raw sewage leaks and spillovers would continue to
occur within the Tijuana River watershed from the deteriorated collector lines. These leaks have
a negative impact on groundwater water quality in Mexico. In addition, on those days when the
Tijuana River flows into the U.S., there potentially could be adverse impacts to groundwater
quality on the U.S.-side from contamination of the river water from raw sewage.

With the proposed action, groundwater quality will improve since there will be a reduction in
raw sewage leaks from the fail from failing collector lines within the Tijuana wastewater
collection system.

During construction, wastewater flows would be diverted to unaffected collection lines within
the Tijuana wastewater collection system.

4.3.3 Floodplains

Floodplains would not be affected under the no action alternative since no construction would
take place with this alternative..

With the proposed action, all construction would be underground within the urban setting of
Tijuana. There would not be any impacts to the volume of surface water flows to the Tijuana
River during construction or operation. In addition, there will not be a substantial change in the
volume of surface water flowing to the Tijuana River from the proposed project, thus there
would be no impacts to floodplains.

4.3.4 Wetlands

Wetlands would not be directly affected by the no action alternative since no construction would
take place.

Wetlands would not be directly affected by the proposed action alternative since no construction
would take place in or around wetlands. In addition, the volume of surface water to the Tijuana
River would not substantially increase, thus there would not be any indirect impacts to wetlands.

4.4 AIR RESOURCES
4.4.1 Air Quality

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No impacts to air quality would occur from the no action alternative.

Under proposed action, impacts to air quality from construction activities would be temporary
and would return to their original ambient levels once construction activities cease. There would
be no longer term impacts to air quality from the proposed project.

4.4.2 Odors

Under the no action alternative, there would be no changes to odors within the project area.
Air quality may be improved with the proposed action since there would be an elimination of
odors within the immediate vicinity of the collection lines.

4.5 NOISE

Due to the highly urbanized nature of Tijuana, there would be not be any significant increase in
noise levels from the proposed action.

4.6 VEGETATIVE RESOURCES

Under the no action alternative, there would be no impacts to vegetative resources since no
construction would occur. For the proposed action, all activities would be within existing streets
in the urbanized setting of Tijuana. Vegetation within the project area is highly disturbed.

4.7 BIOLOGICAL RESOURCES

Under the no action alternative, there would be no impacts to biological resources since no
construction would occur. For the proposed action, all activities would be within existing streets
in the urbanized setting of Tijuana. Vegetation within the project area is highly disturbed and
does not support biological resources.

4.8 CULTURAL RESOURCES AND AESTHETICS

No impacts to cultural resources or aesthetics would occur from the no action alternative. There
would also be no impacts to cultural resources or aesthetics from the proposed action since all
construction would occur in previously developed roadways.

4.9 SOCIOECONOMICS AND ENVIRONMENTAL JUSTICE

There would not be any adverse impacts on socioeconomics or environmental justice
communities from the no action alternative and the proposed project. The proposed project
would eliminate leaks of raw sewage from the wastewater collection main, which would provide
a positive impact to the community within the project area.

4.10 MUNICIPAL SERVICES

Under the no action alternative, there continues to be a risk to human health and the environment
of exposure to raw sewage from failing wastewater collection lines.

Short-term impacts on municipal services from the proposed project would be related to minor
traffic disruption in Mexico during work on roadways and within easements. There would be no
transboundary effects on municipal services for this alternative. Under the proposed alternative,
provisions will be made to maintain wastewater collection service to residents within the project
area during construction. There would be no effects to energy or waste management.

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4.11	PUBLIC HEALTH AND SAFETY

Without an adequate wastewater collection system in Tijuana, exposure to raw wastewater would
continue to occur. This exposure negatively impacts public health in Tijuana as exposure to raw
sewage on streets or in surface waters is a pertinent public health risk. Due to the frequency of
U.S./Mexico border crossing, the public health in the U.S. is also at risk under the no action
alternative, although any potential public health effects directly linked to wastewater from the
project collector lines would be a less than significant impact.

By continuing to use deteriorated collector lines and manholes, a risk of roadway, manhole or
collector collapse would continue. These events, though infrequent, pose a serious risk of
damage to vehicles and are general public safety risk in Mexico.

Public health in Tijuana would be positively affected by the proposed alternative since the
alternative has the potential to eliminate exposure to raw sewage from the overflow of collection
lines. The overall improvement of sanitary conditions within the project area would promote
better overall public health conditions and further provide transboundary benefits by reducing
health risks within the immediate area of the border due to the frequency of U.S./Mexico border
crossing.

4.12	Cumulative Effects

CEQ defines cumulative impacts as an "impact on the environment which results from the
incremental impact of the action when added to other past, present, and reasonably foreseeable
actions regardless of what agency or person undertakes such other actions" (40 CFR 1508.7).
Cumulative impacts can result from individually minor but collectively significant actions taking
place over a period of time by various agencies or individuals. Informed decision-making is
served by consideration of cumulative impacts resulting from projects that are proposed under
construction, recently completed, or anticipated to be implemented in the reasonably foreseeable
future.

The proposed action would rehabilitate or replace 5.5 miles (8.9 kilometers) of collector lines
with diameters ranging from 8 to 42 inches (20 to 107 centimeters) and rehabilitate
approximately 37 manholes and construct an additional 10. These improvements are expected to
generate positive cumulative impacts on both side of the border, since water quality within the
Tijuana River Watershed will be improved. The proposed project is expected to reduce potential
risks to human health and the environment, as well as improve aesthetic conditions within
Tijuana by reducing odors.

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