Imperial Beach City Council
March 15, 2023

Tijuana River Sediment Management Work Plan
i
Funding provided by State Coastal Conservancy through Proposition 68 California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018 resources

F I N A L
Tijuana River Sediment
Management Work Plan
March 2023
Funding provided by State Coastal Conservancy through Proposition 68 California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018 resources Attachment 1

Printed on 30% post-consumer recycled material.

Final Tijuana River Sediment Management Work Plan
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Funding provided by State Coastal Conservancy through Proposition 68 California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018 resources Table of Contents
SECTION PAGE NO.

ACRONYMS AND ABBREVIATIONS .....................................................................................................V EXECUTIVE SUMMARY.......................................................................................................................VII 1 INTRODUCTION ....................................................................................................................1-1

1.1 Tijuana River Watershed Overview................................................................................................... 1-2

1.2 Changing Landscape and Environmental Impacts........................................................................... 1-4

1.3 Sediment Management Overview and Objectives............................................................................ 1-8 2 WATERSHED AND COASTAL PROCESSES.............................................................................2-1

2.1 Riverine Processes ............................................................................................................................. 2-2

2.2 Estuarine Processes........................................................................................................................... 2-2

2.3 Littoral Processes............................................................................................................................... 2-3

2.4 Regional Discussion........................................................................................................................... 2-5 3 TIJUANA RIVER VALLEY SEDIMENT SOURCES .....................................................................3-1

3.1 Sediment Deposition in the Tijuana River Valley.............................................................................. 3-1

3.2 Existing and Potential Sediment Sources ......................................................................................... 3-3 Goat Canyon.......................................................................................................................... 3-5 Smuggler’s Gulch North of Monument Road and Pilot Channel........................................ 3-6 Smuggler’s Gulch South of Monument Road...................................................................... 3-7 Tijuana River Main Channel (Flood Control Channel to Dairy Mart Road)................................ 3-8 Brown Fill Area ...................................................................................................................... 3-9 Tijuana River Estuary..........................................................................................................3-10

3.3 Sediment Sources in Mexico ...........................................................................................................3-11 4 SEDIMENT MANAGEMENT COMPONENTS ..........................................................................4-1

4.1 Excavation/Dredging.......................................................................................................................... 4-2

4.2 Staging and Storage........................................................................................................................... 4-3

4.3 Sediment Characterization and Testing............................................................................................... 4-4

4.4 Processing........................................................................................................................................... 4-5

4.5 Transport............................................................................................................................................. 4-6

4.6 Beneficial Reuse or Disposal............................................................................................................ 4-7

Final Tijuana River Sediment Management Work Plan
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Funding provided by State Coastal Conservancy through Proposition 68 California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018 resources 5 SEDIMENT MANAGEMENT ACTIVITIES/PATHWAYS ............................................................5-1

5.1 Dune, Beach, and Nearshore Nourishment...................................................................................... 5-5

5.2 Thin Layer Sediment Addition............................................................................................................ 5-6

5.3 Levee Rehabilitation........................................................................................................................... 5-7

5.4 Construction and Landscape Material.............................................................................................. 5-8

5.5 Mine Reclamation .............................................................................................................................. 5-9

5.6 Upland Landfill Disposal ..................................................................................................................5-10 6 REGULATORY FRAMEWORK .................................................................................................6-1

6.1 Overview.............................................................................................................................................. 6-1

6.2 Applicable Permits to Relevant Sediment Source Locations and Pathways .................................. 6-5

6.3 Permitting Process/Timeline ............................................................................................................. 6-9 7 MONITORING AND REPORTING ...........................................................................................7-1

7.1 Typical Beneficial Reuse Monitoring Requirements......................................................................... 7-1

7.2 Monitoring Requirements by Type of Beneficial Reuse......................................................................... 7-2 8 RECOMMENDATIONS ...........................................................................................................8-1

8.1 Coordination ....................................................................................................................................... 8-1

8.2 Source Control .................................................................................................................................... 8-2

8.3 Reduce Barriers to Beneficial Reuse ................................................................................................ 8-2

8.4 Permitting Strategies.......................................................................................................................... 8-3

8.5 Data Management.............................................................................................................................. 8-4

8.6 Science Advancement........................................................................................................................ 8-5

8.7 Funding ............................................................................................................................................... 8-5 9 NEXT STEPS AND CONCLUSION ...........................................................................................9-1

9.1 Short Term Goals/ Current Action Items........................................................................................... 9-1

9.2 Long Term Goals................................................................................................................................. 9-3

9.3 Conclusion .......................................................................................................................................... 9-5 10 REFERENCES ........................................................................................................................10-1

Final Tijuana River Sediment Management Work Plan
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Funding provided by State Coastal Conservancy through Proposition 68 California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018 resources

APPENDICES
A Characteristics of Existing and Potential Sediment Sources Table B Draft Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
C Guidelines and Required Forms for the Republic Services Landfills in San Diego D Glossary of Regulatory Terms, Pertinent Agencies, and Applicable Legislation Regulatory Guidelines E Example Monitoring Plans
F Typical 401 Water Quality Certification Permit Conditions for Beach Nourishment Projects in San Diego

FIGURES
1-1 Tijuana River Watershed ................................................................................................................................. 1-2 1-2 Tributaries to the Lower Tijuana River Watershed......................................................................................... 1-3 1-3 Tijuana River Sub-Watersheds Above and Below Dams................................................................................ 1-4 2-1 Natural Sediment Transport Processes (Adapted from CCSMW 2011)....................................................... 2-1 2-2 Example of Longshore Current set up by Angled Wave Approach (Patsch and Griggs 2006) .................... 2-3 2-3 Example of Seasonal Beach Profiles (Adapted from Patsch and Griggs 2006)........................................... 2-4 2-4 Conceptual Model of Sediment Transport Pathways in the Silver Strand Littoral Cell (USACE 1991)....... 2-5 2-5 Sea Level Rise Projections, San Diego Bay, CA (Adapted From OPC 2018 by Moffatt and Nichol)............ 2-7 3-1 Land Ownership and Sediment Sources within the Tijuana River Valley ..................................................... 3-4 TABLES
2-1 Oceanographic Conditions that Influence the Dynamics of the Silver Strand Littoral Cell ......................... 2-6 4-1 Sediment Management Pathway Types and Testing Criteria........................................................................ 4-4 5-1 Sediment Management Alternatives Summary ............................................................................................. 5-3 6-1 Federal, State, and Regional Statutes and Regulations Governing Sediment Management Activities in the Tijuana River Valley .................................................................................................................. 6-2 6-2 Summary of Key Permit Types and Descriptions ........................................................................................... 6-3 6-3 Probable Permit Requirements for Tijuana River Valley Sediment Source Locations................................. 6-6 6-4 Applicable Permits to Relevant Sediment Pathways ..................................................................................... 6-7 6-5 Example permit requirement scenario for excavation of main Tijuana River source area and placement in City of Imperial Beach nearshore environment....................................................................... 6-8 7-1 Probable Monitoring Requirements of Potential Projects ............................................................................. 7-2 7-2 Overview of Anticipated Monitoring Requirements for Beach Nourishment Projects ....................................... 7-3

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Funding provided by State Coastal Conservancy through Proposition 68 California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018 resources

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Funding provided by State Coastal Conservancy through Proposition 68 California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018 resources Acronyms and Abbreviations
Acronym Definition
CCC California Coastal Commission
CDFW California Department of Fish and Wildlife
CESA California Endangered Species Act
cy cubic yard
LCP Local Coastal Program
NMFS National Marine Fisheries Service
RWQCB Regional Water Quality Control Board
SCOUP Sand Compatibility and Opportunistic Use Program Plan S/S stabilization/solidification
SLR sea-level rise
TAC Technical Advisory Committee
TRW Tijuana River watershed
USACE U.S. Army Corps of Engineers
USFWS U.S. Fish and Wildlife Service
Valley Tijuana River Valley
WDR Waste Discharge Requirement

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Tijuana River Valley
Sediment Management Work Plan
Funding provided by State Coastal Conservancy through Proposition 68 California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018
This Sediment Management Work Plan (Work Plan) is
intended to serve as a guide for agencies and organizations responsible for sediment management activities in the Tijuana River Valley (Valley). Sediment management in the Valley is conducted to address flood risk, protect habitat, control pollutants, and increase resilience to climate change. Goals of this Work Plan are to outline strategies to efficiently plan, prioritize, and implement sediment management activities through collaborative partnerships and a consistent regulatory framework, and establish a roadmap for streamlined sediment management in the Valley.

Rain events and watershed dynamics distribute sediment to low-lying areas and receiving waters. The Valley is the terminus of a large binational watershed with significant sediment and trash transport challenges. Agencies with habitat management and flood management responsibilities in
the Valley, including federal, state, and local stakeholders, perform sediment management activities resulting in the excavation of large amounts of sediment. Sediment management in this context is considered the process of onetime or periodic handling, treatment, and beneficial reuse or disposal. Beneficial reuse and/or disposal of excavated Plan Prioritize
Tijuana River Valley
Sediment Management Planning Framework
Regulatory
Compliance
Implement
Collaborative
Partnership
sediment has been a long-standing challenge due to watershed configuration and nearby coastal dynamics, logistics, costs, regulatory compliance, and public perception.

This Work Plan provides a Valley-specific framework for sediment management options with stakeholder input-derived recommendations to support short- and long-term goals for optimization of sediment beneficial reuse and disposal processes. The Work Plan provides an overview
of the watershed, areas with sediment management need
(sources), summary of processes used to excavate, handle, and transport sediment, common beneficial reuse and
disposal pathways, and a synopsis of associated regulatory permitting elements including monitoring and reporting.

Key Watershed Metrics
~ 1,750 sq. mi. watershed
~ Dense urban development
~ Diverse, sensitive habitats
~ Binational sediment
management challenges
February 2023
The Goat Canyon sediment basins are a key source area
requiring ongoing management and sediment export.

Executive Summary

Work Plan contents are intended to guide and support
agency planning and implementation activities.

Important follow up actions outlined in this Work Plan are for affected agencies to take proactive steps to:
• Coordinate with key stakeholders to facilitate efficient sediment management;
• Maximize source control in upstream areas and Mexico
to minimize anthropogenic contributions to sediment
loads;
• Reduce barriers to beneficial reuse by performing pilots to refine implementation strategies, coordinate with
regulatory agencies, and perform collaborative work to
maximize cost-efficiency and environmental
protections;
• Develop standard and streamlined permitting strategies in collaboration with appropriate regulatory agencies;
• Develop and maintain a centralized data repository for sediment management information and data to support activity planning, permitting, and implementation; • Support science and technology advancements to
enhance understanding of sediment fate and transport
and improve management policies and projects; and
• Develop a comprehensive program to identify, develop, and route sustainable funding sources toward Valley
sediment management needs.

The recommendations presented in this Work Plan are
intended to support successful implementation of sediment management projects throughout the Valley over the next decade and beyond. The Work Plan outlines series of shortterm and long-term goals to work toward overcoming known sediment management hurdles. Short-term goals aim to
leverage existing processes and programs to facilitate
agency collaboration to standardize and optimize sediment management planning and implementation efforts. Longterm goals build on the short-term actions and emphasize a multiagency, coordinated approach to sediment management to the level of formalized partnerships and
streamlined project implementation. These efforts would be supported by research/pilot projects, consistent, regional funding, and aligned with resource agency goals.

Funding provided by State Coastal Conservancy through Proposition 68 California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018
Periodic excavation of channel conveyances to reduce flood risk requires cost-efficient sediment reuse and disposal options.

Historic quarry restoration through placement of clean
excavated sediment provides a beneficial reuse option.

Sediment placement in nearshore environment may provide sustainable, long-term management solution with multiple benefits.

February 2023
Quarry Restoration Design
Plan (Final Design)
Tijuana River Valley
Sediment Management Work Plan

SECTION 1
Introduction
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1 Introduction
This Tijuana River Valley Sediment Management
Work Plan (Work Plan) provides a summary of
sediment management needs and opportunities for
the Tijuana River Watershed (TRW). Within the
context of this report, sediment management is
considered the process of one-time or periodic
handling, treatment, and potential disposal or
beneficial reuse options for known and anticipated
areas of sediment accretion in the lower TRW.

Given the diverse and sensitive habitat types;
presence of intermingled and overlapping federal,
state, and local jurisdictional and regulatory agency
stakeholders; and dynamic watershed-scale
processes that coalesce in the lower watershed,
active environmental and sediment management is
needed to address flood risk, protect habitat,
control pollutants, increase resilience to climate
change, and create efficiencies in permitting and
regulatory compliance for projects and activities
that provide repeatable and sustainable benefits.

Watershed systems are dynamic landscape
features that transport precipitation through
streams and rivers to the ocean and other receiving
waters. A natural function of this process is the
downstream transport of sediment and debris as
part of routine and episodic events. In the TRW,
sediment transported from upstream natural and
disturbed watershed areas converges in the lower
TRW or Tijuana River Valley (Valley) through
contributions from the main Tijuana River and
several prominent tributaries in both the United
States and Mexico. The Valley also supports a
diverse array of critical habitats and infrastructure,
serving as a hydrological and biological crossroads,
where there is interaction between upland,
wetland, estuarine, and ocean environments.

Within this unique ecological and important Southern
California coastal community environment,
management of sediment delivered from natural
watershed processes and human interventions serves
as a critical conservation element. Previous work has
Sediment management is needed in the TRW to address
flood risk, habitat, and pollutants and create efficiencies in permitting and regulatory compliance to create
sustainable benefits.

Key goals of this effort are to
provide a programmatic
pathway to plan, prioritize, and
program future coastal sediment
management activities, develop
a collaborative agency approach
to provide a consistent
framework for project
proponents, and establish a
roadmap for streamlined
sediment management-related
project approvals in the Valley.

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identified sediment management and beneficial reuse
as a key project need for the Valley (TRVRT 2013;
County of San Diego 2020a). However, sediment
management within the context of distinct projects and
multi-agency efforts includes coordination, cost,
contaminant, and permitting constraints that have
challenged project implementation (Goodrich et al.
2019). This Work Plan outlines current conditions,
sediment management needs, available strategies that
may maximize the local beneficial reuse of sediment,
and preliminary implementation feasibility assessments
for the Valley. The Work Plan addresses the unique
sediment management challenges identified for the
Valley and develops a framework for stakeholders and
resource agencies to identify optimal sediment
management, beneficial reuse, and disposal options.

1.1 Tijuana River
Watershed Overview
The TRW is a binational drainage basin that covers
approximately 1,750 square miles in southern
San Diego County, United States, and northern Baja
California, Mexico (Figure 1-1). Approximately 73% of
the watershed lies in Mexico, and 27% in the United
States (USACE 2020). The watershed is
characterized by steep, hilly terrain and a
Mediterranean climate. Vegetation cover is
dominated by chaparral and coastal sage scrub,
along with wetlands (vernal pools and riparian
zones) and oaks and conifers in the mountains. The
Laguna Mountains in California and Sierra de Juárez
Figure 1-1: Tijuana River Watershed

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Mountains in Baja California feed the roughly
120-mile-long Tijuana River that enters the United
States approximately 6 miles from the Pacific Ocean
near the community of San Ysidro. In the United
States, the Tijuana River receives flow from
Cottonwood Creek and Pine Creek before traversing
the U.S./Mexico border. In Mexico, the Río
Las Palmas and Rio Alomar systems feed the Tijuana
River prior to re-entry into the United States
(USACE 2020). Once across the border, the Tijuana
River traverses the Valley before entering the Tijuana
River Estuary and discharging into the Pacific Ocean
just south of the City of Imperial Beach, California.

Several tributary areas join the lower river in the
Valley on the U.S. side of the border with Mexico
(Figure 1-2). Three main tributary drainages include
Smugglers Gulch (El Cañon del Matadero), Goat
Canyon (Cañon Los Laureles) and Yogurt Canyon
(Cañon Los Sauces). Additionally, several smaller
cross-border discharge points contribute flows to the
lower river including Stewart’s Drain, Silva Drain, and Canyon Del Sol. Each of these tributary drainages are
highly urbanized and contribute significant trash, waste tires, and erosion of sediment from steep canyon walls.

Varied land uses are present in the TRW. The upper
watershed is largely undeveloped open space and
includes diverse habitats like pine forest, chaparral,
and riparian areas. In the middle and lower
watershed, urbanization clustered adjacent to the
border in both Mexico and the United States has led
to a mixture of open space and disturbed land,
residential, commercial, military, and industrial areas.

The City of Tijuana in Mexico is the largest urban area within the watershed. Tijuana covers approximately
246 square miles and is home to approximately 2.2
million people as of 2022 (PopulationStat 2021). In
the United States, urbanized portions of the
watershed are generally within the jurisdiction of the
County of San Diego, City of San Diego, and City of
Imperial Beach.

Figure 1-2: Tributaries to the Lower Tijuana River Watershed

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1.2 Changing Landscape and
Environmental Impacts
Anthropogenic alterations in the TRW over the past
150 years, including urban and agricultural land
development, dam construction, and channelization
of the Tijuana River, have led to changes in
watershed form and function in the Valley. Prior to
these changes, the watershed had a rich,
heterogeneous landscape. The Tijuana River
floodplain was more than 1 kilometer wide and
densely vegetated. Floodplain habitats included
sandy river wash, dense riparian scrub, and
groundwater-fed ponds (Safran et al. 2017).

Perennial freshwater wetlands, vernal pools, and
alkali meadows were present, and upland areas
included grassland and coastal sage scrub. The wider
and often braided mainstem of the river shifted
greatly with periodic high flow events that punctuated
long, dry periods.

In the early to mid-1900s, several large dams were
built in the TRW (Barrett and Morena in the United
States and Rodríguez and El Carrizo in Mexico), which
now control a large majority of the surface water flow
in the watershed (USACE 2018) (Figure 1-3). While
these dams provide reservoirs of potable water to
support residents and associated infrastructure on
both sides of the border, they also serve as traps for
the downstream movement of sediment to the lower
watershed. Further, controlled releases from the
dams, along with urban stormwater, wastewater, and
agricultural runoff, have contributed to the shift to
perennial streamflow in the Valley.

Urban and agricultural development now occupy more
than two-thirds of the Valley. With these
Figure 1-3: Tijuana River Sub-Watersheds Above and Below Dams

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developments came changes in Tijuana River
hydrology, sediment transport, and groundwater
levels, which led to significant changes in floodplain, habitat, and estuary characteristics. The change in
flow regime and channelization of the Tijuana River
has reduced geomorphic diversity and in turn habitat
diversity. Significant habitat loss has occurred,
including much of the wetlands that once dominated
the valley floor (Safran et al. 2017). It is estimated
there has been a decrease of 40%–80% in every
major historical habitat type in the U.S. portion of the TRW and more than 90% in Mexico as compared to
pre-urbanization conditions (Safran et al. 2017).

Further, the hydrology and hydraulic modifications
have contributed to conversion of habitat types,
including the shift from riparian scrub to riparian
forest along the river corridor and from unvegetated
tidal flats to vegetated salt marsh in the estuary.

Historic sediment transport of the Tijuana River and
estuary to the nearshore ocean environment has
been greatly disrupted (CDPR 2008). Dams operating
for flood control hold back the peak runoff from a
storm and release the flow over time at a level more
manageable for downstream infrastructure. While this
is beneficial for downstream communities, it reduces
the sediment transport capabilities of the river.

Therefore, even though urban and agricultural
development has locally increased erosion below the
dams, there is not enough flow to carry the sediment
to the ocean and nourish the nearshore environment.

This condition leads to accumulation in tributaries
and in the Tijuana Estuary. Further, the sedimentladen flows create significant management challenges as they damage critical infrastructure and
impair water quality (Biggs et al. 2018). The Tijuana
Estuary is a National Estuarine Sanctuary that
supports a variety of threatened and endangered
plants and animals that are sensitive to changing
sediment inundation regimes.

The challenge of increased erosion and reduced
sediment transport in the Valley is compounded by
the associated increases in trash and pollutant
discharges. A significant amount of waste tires and
trash accumulate in the TRW each year. River flows
containing coliform bacteria, trace metals, and other
urban, agricultural, and industrial pollutants in
addition to anthropogenic (human-induced) sediment
threaten the health of downstream habitat
(CalRecycle 2010). Water quality degradation from
non-point agricultural sources in the United States
and both point and non-point sources in Mexico has
resulted in the classification of the Tijuana River as a Category 1 (impaired) watershed by the California
State Water Resources Control Board. A Total
Maximum Daily Load to address bacteria and trash
impairments is in development by the San Diego
Regional Water Quality Control Board (RWQCB 2022).

The following two pages illustrate the impacts of
development in the Valley.

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sediment_management_urbanization_6 (2

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1.3 Sediment Management
Overview and Objectives
Tijuana River sediment management in the United
States is focused on the lower TRW, or Valley, which
includes the downstream end of the Smuggler’s
Gulch, Goat Canyon, and Yogurt Canyon subbasins
and the Tijuana River mainstem extending from the
border to the estuary and ocean. It is assumed that
the sediment and trash produced in the 462-squaremile area downstream of the dams are the areas with most significant impacts to the Valley. Sediment is
produced and transported naturally through
watershed processes, but also can occur as a result
of anthropogenic disturbance. Sediment is critical to
the function of habitats within a river system and
estuary; however, increased sediment delivery as a
result of anthropogenic disturbance poses multiple
issues, including but not limited to impacts to riparian and estuarine habitat due to burial from excessive
deposition, restriction of flood conveyance and tidal
influence through excessive deposition in and
obstruction of channels, and the introduction of
unnatural turbidity and contaminants
Management of sediment can follow two distinct paths:
beneficial reuse or disposal. Beneficial reuse refers to the repurposing of sediment from a waste product into
a resource. Conversely, disposal refers to the framing of sediment as a waste material or byproduct of an activity such as sediment capture or dredging.

Understanding the science of sediment transport in
the Valley and nearshore environment is critical to the sediment management project planning process. It is
equally important to understand and navigate the
challenging coordination, cost, contaminant, and
permitting constraints that have hindered sediment
management projects in the past (Goodrich et al.
2019). As such, this Work Plan provides an overview
of the following topics:
• A description of the physical processes that
drive sediment transport and deposition
• Tijuana River sediment sources
• An overview of sediment
management components
• Sediment management activities and
pathways, including project examples
• Regulatory framework
• Monitoring and reporting considerations
• Preliminary implementation
feasibility assessments
• Strategies to maximize local beneficial reuse
of sediment
In addition to compiling the above information, the
main objective of this Work Plan is to provide a
framework for stakeholders and resource agencies to
identify optimal sediment disposal options. The Valley
is host to multiple regulatory agency stakeholders
with often overlapping jurisdiction and varied
objectives, including flood risk reduction and water
quality and habitat and sensitive species protection.

Sediment management in the Valley requires a
collaborative effort and, where possible, streamlining
of regulatory requirements for projects that benefit
the environment.

Anthropogenic disturbance such as urban and agricultural development in the TRW has impacted sediment transport
to the Valley.

SECTION 2
Watershed and Coastal Processes
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2 Watershed and Coastal Processes
Physical processes relevant to this Work Plan
include riverine and ocean sediment transport
processes. Generally speaking, sediment is eroded
from upland sites during storm events and/or
anthropogenic disturbances and is carried through
streams to the coast. In an estuary environment,
sediment transport is affected by tidal exchange.

Once sediment reaches the ocean it is subject to
the dynamic forces of tides, waves, currents, and
wind. The typical lifecycle a grain of sand
undergoes is summarized in the following text and
depicted in Figure 2-1 (CCSMW 2011).

Sediment deposition occurs when flow velocities
decrease below the level at which transport can be
sustained, such as in relatively more “quiet” or
sheltered zones within a watershed and along the
coast. These sheltered zones can occur in the
Figure 2-1: Natural Sediment Transport Processes (Adapted from CCSMW 2011)

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floodplain, river channels, estuary and inlet, and
the open ocean. Finer sediment, such as silts and
clays, are more easily transported than coarser
sediments, which range from sand to cobble to
rock. Sediment deposition in river, estuary, and
ocean environments is described in detail in the
following sections.

2.1 Riverine Processes
To transport sediment from upland to the estuary,
river flow velocity must meet or exceed the
necessary velocity to move sediment along the
stream channel bed (i.e., bed load) or entrain
sediment and transport it in the water column (i.e.,
suspended load). Sediment will deposit at bends in
the river planform where water flow velocities drop
at the inside of a bend, forming a “point bar.” If the
stream is not in equilibrium state (common in areas
of anthropogenic disturbance) and is unable to
transport the sediment load, sediment may deposit
in bars within the active channel. Sand bars can
then recruit riparian vegetation. Once established,
the riparian vegetation can impose greater friction
to subsequent flows thus slowing velocities and
causing more sedimentation. This can become a
perpetuating loop with progressive buildup of
sediment over time (accretion or aggradation) and
expansion of the riparian habitat area. This effect
can cause the stream course to rise in elevation
and change in geomorphology and function.

Coarsest grade sediments, such as rocks, cobbles,
and pebbles, deposit first because they are heavier
than finer-grained sediments. This is followed by
deposition of progressively finer-grained sediments,
such as sand, silts and clays, with increased
distance downstream.

Flood events are a key component to the riverine
sediment transport process. High stormflows have
much greater capacity to scour and transport
sediment than low flows due to the exponential
increase in flow velocities (and sediment carrying
capacity) with increased flow discharge. As
mentioned above, the presence of riparian
vegetation can promote additional sedimentation
by trapping sediment during higher flows. Riparian
areas then grow as a portion of channel converts to
river terrace or upland. The movement of sediment
with varying flows accounts for a river’s geomorphic
change over time.

2.2 Estuarine Processes
At the coast, finer-grained sediment is deposited in
riverine estuaries. Riverine estuaries interact with the open ocean, creating brackish waters and unique
ecosystems such as beach, dune, salt marsh,
brackish marsh, riparian, and upland ecosystems
within and adjacent to the floodplain. During low
rainfall periods, the estuary becomes more tidally
influenced as oceanic transport deposits sediment in
the vicinity of the river mouth (i.e., tidal inlet). This sediment delivery results in shoaling just inside the
estuary (flood shoal), outside of the estuary (ebb
shoal), and within the actual inlet channel. The tidal
inlet geomorphology responds by constricting during
neap tides (low range tides during quarter moons)
and scouring during spring tides (large range tides
during new and full moons. During high rainfall
periods (stormflow events), flood waters carry and
deposit sediment, mostly silts and clays, across the
floodplain and impact salt marsh habitat distribution
in the tidal estuary.

The estuary is home to salt marsh habitat that
consists of both vegetated and unvegetated
intertidal sub-habitats. Vegetated salt marsh
habitats colonize at specific elevation ranges
relative to long-term average tidal elevations, and
thus are subject to change over time as river
dynamics may change sedimentation patterns
within the estuary, and as sea-level rise (SLR)
impacts water levels. It is anticipated that with
SLR, vegetation at lower tidal elevations may die
off while vegetation at upper elevations may
expand if there is area to colonize. The resulting
process is a transgression of salt marsh habitats
upward. If SLR occurs without sedimentation, the
area of available ground to colonize may decrease
over time and vegetated salt marsh habitat may
eventually be eliminated.

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2.3 Littoral Processes
Once sediment reaches the ocean, sediment
transport is completely influenced by waves and
currents caused by a combination of forces that move
along and across the shore. Sediment transport along
the coast, called “longshore sediment transport,”
occurs within geographically distinct compartments
called littoral cells. The littoral zone extends from the highest reaches of the waves on a beach out to water
depths of approximately −30 feet relative to the mean
lower-low water level in Southern California. The
littoral zone is the band or ribbon of sediment
transport along the coast. This band of littoral
sediment transport is interrupted by natural and
human-made features extending outward into the sea
such as large points, promontories/headlands,
submarine canyons, harbors, and jetties.

Oceanographic conditions that influence the
dynamics of a littoral cell include tides, waves,
currents, storm surges, and SLR. These
oceanographic conditions, combined with
characteristics of the coast such as its orientation,
planform, slope, sand grain size, and volume,
determine the sand transport rate and direction over
time and space. This process can vary along a coast
depending on the shoreline condition and exposure to
oceanographic forces. For instance, a coast that is
acutely angled to the direction of wave approach and
exposed to high wave energy may experience a high
sediment transport rate if there is sufficient sand in
the system to be moved. Conversely, coasts oriented
more parallel to the direction of wave approach tend
to experience a lower rate of sediment transport,
given the same sand supply.

Sediment may be transported with the longshore
current in one direction for some time, then
transported in the reverse direction in a season with
an opposing wave approach angle (Figure 2-2). On a
yearly timescale, gross sediment transport refers to
the total volume moved in directions combined (e.g.,
north and south), while net transport is the difference between north and south transport rates and
represents the annual amount of sediment moving in
the dominant direction, also termed littoral drift.

Cross-shore sediment transport, the movement of
sediment perpendicular to the shore, is primarily
characterized by contrasting winter and summer
dynamics. Stormy winter months tend to temporarily
move sand off of the shore into nearshore bars
causing narrowing of beaches and widening of the
wave breaking zone. Sediment typically returns during
the summer’s relatively calm wave climate, widening
the beaches and narrowing the nearshore zone of
breaking waves (Figure 2-3) (Elgar et al. 2001).

A description of littoral processes specific to Southern California and northern Baja California, which impact
estuary management and beneficial reuse of
sediment at the coast, is included in Section 2.4,
Regional Discussion.

Figure 2-2: Example of Longshore Current set up by Angled Wave Approach (Patsch and Griggs 2006)

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Figure 2-3: Example of Seasonal Beach Profiles (Adapted from Patsch and Griggs 2006)

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2.4 Regional Discussion
In coastal Southern California and northern Baja
California, sediment transport is largely driven by
episodic rainfall, which leads to runoff, erosion, river flow, and discharge to the ocean. The region’s
Mediterranean climate generally drives a dry summer
season and wet winter season. Furthermore,
extended droughts commonly occur, with intermittent
wet years often brought on by the Pacific Decadal
Oscillation and resultant El Niños. High stormflows
have an incredible capacity to transport sediment.

One example of this is a 100-year storm event that
essentially flushed the Tijuana River floodplain of
sediment and left it in a large delta in the ocean
offshore. Following high stormflows, subsequent
lower flows resume sediment deposition over time
within the floodplain. The cycle of flooding, erosion,
and sediment transport, along with anthropogenic
influence, accounts for the continuous evolution of
the river’s course. The Tijuana River has shifted
position laterally by up to 1 kilometer in a single storm event (Safran et al. 2017).

The Tijuana River empties into the Silver Strand
Littoral Cell. Figure 2-4 depicts the Silver Strand
Littoral Cell, which is defined as an approximately
17 mile geographic reach of coastline beginning
3 miles south of the U.S./Mexico border at the Playas
de Tijuana headland and continuing north to Zuniga
Jetty at the entrance to San Diego Bay (USACE 1991).

Patsch and Griggs (2006) estimate gross sediment
transport throughout the Silver Strand Littoral Cell to be approximately 740,000 cubic yards per year and
net longshore sediment transport is to the north from
between 120,000 and 200,000 cubic yards per year.

Oceanographic conditions that influence the
dynamics of the Silver Strand Littoral Cell and thus
sediment management and beneficial reuse in the
region are described in Table 2-1.

Figure 2-4: Conceptual Model of Sediment Transport Pathways in the Silver Strand Littoral Cell (USACE 1991)

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Table 2-1. Oceanographic Conditions that Influence the Dynamics of the Silver Strand Littoral Cell Oceanic
Condition Southern California/Baja California Conditions Sediment Transport Considerations Tides • Astronomical tides: mixed semidiurnal, with two high tides and two low tides of different
magnitude occurring each lunar day (an
approximately 25-hour time period). Account for
the most significant amount of variation in the
total water level, ranging approximately

5.72 feet between the mean lower-low water
level and the mean higher-high water level.
1 • King tides: largest tides of the year, occurring in winter and summer. High tides exceed the
average mean higher-high water level by up to
2 feet or greater.
• El Niño-southern oscillation cycles: can cause
water level increase due to thermal
expansion, strong onshore winds, and air
pressure changes.
• Storm surges: can cause water level increase
due to thermal expansion, strong onshore
winds, and air pressure changes.
• Dry-weather water level variations
caused by tides play a primary role in
estuarine dynamics, including
geomorphic evolution, water circulation,
habitat establishment, and resilience.

Waves • Predominant wave exposure: west-northwest
swell generated by Gulf of Alaska storms and
south-southwest swell from the southern
Hemisphere.
2 In summer, the California highpressure system generates additional northwestern swell from local sea breezes.
• Wave height: swell waves tend to peak in
height and period in the winter, although
southern swells can have very long periods.
• Wind/storm waves: less frequent exposure to
other wind and storm generated waves from
the south and southwest.
2 • Waves entrain sand.
• Waves drive cross-shore and longshore
currents.
• Waves can cause short-duration coastal
flooding events due to dynamic
increases in water levels and wave
runup, and in turn impact sediment
transport.

Currents • Longshore currents: wave-driven currents
parallel to shore.
• Cross-shore currents: wave-driven currents
perpendicular to shore. In this region, stormy
winter months tend to temporarily move sand
off of the shore into nearshore bars causing
narrowing of beaches and widening of the wave
breaking zone.
• Longshore currents are the vehicle for
longshore sediment transport, the
movement of sediment parallel to the
shore. Sediment may be transported in
one direction for some time, then
transported in the reverse direction in a
season with an opposing wave
approach angle.
• Cross-shore currents carry sediment
perpendicular to the shore.

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Table 2-1. Oceanographic Conditions that Influence the Dynamics of the Silver Strand Littoral Cell Oceanic
Condition Southern California/Baja California Conditions Sediment Transport Considerations Sea Level
Rise
• Sea-level rise (SLR) predictions:
3 For the 2030-
time horizon, the likely range of SLR for San
Diego is 0.4–0.6 feet. At the 2050-time
horizon, the likely range of SLR increases
slightly to 0.7–1.2 feet. The likely range of SLR
at the 2100-time horizon is 1.8–3.6 feet.
• Sedimentation rates have historically met or
exceeded the rate of SLR, allowing marsh
habitats to persist. However, the rate of SLR is
projected to accelerate significantly,
introducing the potential for habitats to be
submerged and ultimately changed to different
habitat types (e.g., vegetated habitat may
change to unvegetated habitat).
• Sedimentation rates below SLR rates
may result in a subtidal basin rather
than an estuary, and sedimentation
rates above SLR rates can promote
expansion of salt marsh habitat and
resilience over time.
• Sediment may become a more
important commodity to retain within
estuaries if the goal is to retain
vegetated salt marsh habitat.

Notes:
1 NOAA 2021.
2 Ludka et al. 2019.
3 The current best-available science for potential SLR was prepared by the Ocean Protection Council (OPC 2018).

SLR in Southern California is projected to occur
exponentially as shown in Figure 2-5. The long-term
impact of SLR on the Tijuana River Estuary and its
salt marsh habitat is of particular importance to
sediment management planning. Ocean shoaling
may occur farther into the estuary, while river
sedimentation may also occur differently,
depending on the landward extent of the
seawater/freshwater interface. Ultimately, there
may be a transgression of salt marsh habitats
upward, and if there is a lack of sedimentation
providing new ground to colonize, salt marsh
habitat may decline and eventually be eliminated.

As discussed in Section 1.2, other anthropogenic
impacts to sediment transport processes are
developments for water storage, flood control, and
urban development, which have been shown to
Figure 2-5: Sea Level Rise Projections, San Diego Bay, CA (Adapted From OPC 2018 by Moffatt and Nichol)

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decrease the sand supply to the coastline. Increased
development, including dam construction, in the
southwestern area of the United States and in
Tijuana, Mexico, in modern times has affected the
morphological state of the region’s beach
environments and offshore sediment sinks. The
change in sediment transport in the TRW has left
regional areas such as the Silver Strand Littoral Cell
with an annual deficit, meaning that, without
intervention, the region is in an annual state of
erosion. Although a sediment deficit at the coastline
may sound counter-intuitive when a significant
amount of erosion caused by development in Tijuana
is smothering the Tijuana Estuary and River habitat
located in the United States, diminished peak river
flows have reduced the sediment carrying capacity
(i.e., sediment transport) of the Tijuana River.

In part to offset this deficit, the Silver Strand Littoral Cell has been the recipient of significant beach
nourishment projects. Prior to the year 2000, nearly
35 million cubic yards (cy) of sand was placed on its
beaches, making it the most highly altered length of
shoreline in Southern California (Flick 1993). Since
then, two major beach nourishment efforts, Regional
Beach Sand Projects I and II, placed an additional
120,000 cy and 450,000 cy in 2001 and 2012,
respectively (SANDAG 2020). As a result, today the
Silver Strand is characterized by relatively wide sandy beaches. However, beach erosion is still actively
occurring, especially south of Coronado and at
Imperial Beach. Bluff erosion has also been
experienced along the coast of Tijuana, Mexico.

SECTION 3
Tijuana River Valley Sediment Sources
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3 Tijuana River Valley Sediment Sources
This section provides an overview of sediment
deposition patterns in the Valley. Existing and
potential sediment sources including specific
sediment locations, ownership, typical availability, and sediment characteristics are also presented. General
sediment sources for use in sediment management
projects include uplands, the channel/flood corridor,
reservoirs, sediment basins, and the estuary.

3.1 Sediment Deposition in
the Tijuana River Valley
Development in the TRW, including construction of
dams in the upper watershed and of large urban
areas within the lower watershed, has changed how
and where sediment deposits in the Valley. Prior to
development of dams and other flood control
infrastructure, sediment deposition likely occurred
more frequently and was distributed more broadly
throughout the watershed. Ephemeral tributaries
drained into the Valley through numerous canyons
and washes to the east and south, depositing
sediment slowly as they meandered toward the
mainstem of the Tijuana River (Safran et al. 2017).

Sediment carried by the mainstem of the river
gradually deposited at the outlet creating the flat
plain of the Tijuana River Estuary as we know it today.

In present day, dams have impounded sediment in
the upper watershed while increased urbanization
and development below the dams have caused an
acceleration of sediment input into the Valley and
estuary. The acceleration is caused by vegetation
removal, replacement of naturally vegetated ground
surfaces with impervious surfaces, and
collection/concentration of storm drainage. Under
these conditions, exposed soil erodes, is carried
swiftly downstream with concentrated runoff, and
deposits when it reaches the flat areas of the Valley.

As a result, sediment has accumulated at higher rates
within the tributary canyons and washes in the Valley,
as well as on the floodplain itself. Sediment
accumulates and is trapped in the estuary, impacting
estuarine processes and habitat, while the beaches
and nearshore environment are starved of sediment.

The majority of erosion and sediment deposition
within the TRW occurs during high flow events.

Under current conditions, discharge for a 1% annual
exceedance probability flood (100-year flood) in the
TRW is estimated to be 67,100 cubic feet per
second (USACE 2018). The 100-year flood event is
estimated to transport approximately 712,070 cy of
sediment to the open ocean, 51% of which is
considered to be fine material (silts and clays), and
49% of which is considered to be very fine sand or
coarser (USACE 2020). Two recorded flood events
that exemplify the potential for sediment transport
within the Valley occurred in 1937 and 1983, which
together transported a total 20 million cubic yards
across two singular events. To provide perspective,
the peak annual river discharge has ranged from
near 0 to 30,088 cubic feet per second, with an
average peak discharge of 2,407 cubic feet per
second, recorded by the International Boundary and
Increased urbanization has resulted in accelerated sediment in the Valley and estuary, which has impacted estuarine processes and habitat.

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Water Commission at the international border gauge
no. 11013300 (Safran et al. 2017).

The locations of sediment accumulation in the Valley
follow general patterns related to the watershed
processes that were described in Section 2. Under
current conditions, sediment deposition occurs in
bars within the mainstem of the Tijuana River and at
point bars that form around bends in the tributaries,
where flow velocities drop in these meandering
channels. In the lower mainstem of the river, just
downstream of the international border in the vicinity
of Dairy Mart Road (see Figure 1-2 for location),
channelized river flow rapidly fans out as the width of the floodplain increases, creating another sediment
deposition area. Willow trees colonize a very large
area of the lower river from Dairy Mart Road to
approximately 1 mile downstream of Hollister Street,
within a half mile of the upstream end of the estuary.

The willows promote additional sedimentation within
this reach. Downstream of this riparian area there is a broad transitional zone to where the farthest
upstream influence of the tides occurs. Less
sedimentation occurs within this reach because the
willows have trapped a significant amount of the
sediment. This section of the main river corridor is
more natural in function and sedimentation than the
smaller tributaries that meet the floodplain farther
downstream. However, it is still highly humaninfluenced due to the existence of the concrete flood channels through Tijuana.

The downstream end of the Tijuana River meets with
the upstream end of the estuary between the
locations of the Naval Outlying Landing Field Imperial
Beach and Goat Canyon, approximately 1.3 miles
Significant erosion and sediment transport with the TRW occurs during high flow events.

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upstream from the ocean. Tributaries to the Tijuana
River contribute sediment within this reach through
Smuggler’s Gulch, Goat Canyon, and Yogurt Canyon.

These tributaries deposit sediment at discharge
points along the southern boundary of the Valley.

Sediment sizes range broadly from rock to silt
because of lack of sediment and drainage control
south of the border, very steep-gradient watersheds,
and the “flashy” nature of urbanized runoff, that is,
runoff exhibiting a hydrograph with steep vertical
jumps and rapid declines. The tributaries are highly
impacted by anthropogenic disturbance and transport
pollutant-laden deposits. Finally, silts and clays are
deposited within the relatively quiet waters of the
intertidal zone. Closer to the beach the sediment
deposited within the estuary is sandier than within the interior estuary and is deposited by incoming tidal
currents from the ocean. Sand bars form at the
mouth as a flood tidal delta within the estuary, and an ebb tidal delta exists just offshore in the ocean.

3.2 Existing and Potential
Sediment Sources
This section includes TRW sediment source locations
and ownership information, as well as details on
quantity, quality, and timing of availability to aide in sediment management and reuse or disposal
planning. Currently, management of sediment in the
Valley is carried out by various local, state, and federal agencies, reflecting the patchwork of ownership and
jurisdiction over various sediment sources (Figure 3-1). 1 Brown Fill Area was evaluated as a potential sediment source, the amount of sediment available may be a
limiting factor for re-use opportunities.

Sediment quantities, characteristics, and quality at
various locations within the Valley have been
evaluated in numerous studies over the past two
decades. A comprehensive literature review was
conducted for existing and potential sources of
sediment for reuse or disposal, including the following sites: Goat Canyon Sediment Basin Complex,
Smuggler’s Gulch north of Monument Road and Pilot
Channel, Smuggler’s Gulch south of Monument Road,
Tijuana River Main Channel (Flood Control Channel to
Dairy Mart Road), Brown Fill Area,
1 and the Tijuana
River Estuary. Appendix A presents a summary of
available information reviewed, as well as results
from the recent Tijuana River Valley Sediment
Management Plan and Monitoring Program Technical
Results Memorandum (Appendix B) conducted in
support of this Work Plan. The Technical Results
Memorandum included sediment and water quality
sampling and trash evaluations.

Under Senate Bill 507, proposed projects are being
considered for the Tijuana River, of which the
following directly relate to sediment: new
sedimentation basins in the Tijuana River and
Smuggler’s Gulch, a pilot channel in Yogurt Canyon,
and Nelson Sloan Quarry Restoration and soil
sampling. Proposed projects indirectly related to
sediment include installation of trash booms, nongovernmental organization clean-up programs, water quality monitoring, low-flow diversions, instream water quality detention basins, flow diversions, and water treatment (County of
San Diego 2020a, 2020b).

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Figure 3-1: Land Ownership and Sediment Sources within the Tijuana River Valley

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Goat Canyon

3.2.1 Goat Canyon

SEDIMENT SOURCE
Constructed in 2005, the purpose of the
Goat Canyon Sediment Basin Complex is to
reduce cross-border sediment impacts to
infrastructure and the Tijuana Estuary.

Location Lower reach of Goat
Canyon/Los Laureles Canyon near
Monument Road in Border Field
State Park
Ownership California State Parks
Type of Source Constructed
sediment basins
Size 19 acres
Estimated Annual Sediment Yield
25,000–60,000 cubic yards
Maintenance Annual; includes
processing to remove trash/debris
at an on site processing area
Other Considerations When at
capacity, sediment-laden flows are
bypassed to areas downstream
including the Model Marsh
(associated with the Tijuana Estuary
Tidal Restoration Program)
Summary of Sediment Characteristics
Particle Size
(approximate)
60% sands,
40% fines
Color Light gray to pale
olive, micaceous
Contaminants No hazardous waste
Trash Rating Very High
See Appendix A for additional detail and references
Location of Goat Canyon Sediment Basins
Goat Canyon Upper Basin
Prior to Excavation (2022)

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Smuggler’s Gulch North
of Monument Road and Pilot Channel

3.2.2 Smuggler’s Gulch North of
Monument Road and Pilot Channel

SEDIMENT SOURCE
Location Smuggler’s Gulch is a
tributary to the mainstem Tijuana
River in the vicinity of Monument
Road and Hollister Avenue; Pilot
Channel is a section of the Tijuana
River Mainstem at the confluence
with Smuggler’s Gulch
Ownership City and County of
San Diego
Type of SourceManaged natural channel
Size Smuggler’s Gulch north of
Monument Road is 0.5 miles long;
Pilot Channel is 1 mile long
Estimated Annual Sediment Yield
200–30,000 cubic yards combined
Maintenance Annual and poststorm event; includes processing to remove trash/debris at an on site
processing area
Other Considerations A proposed
sediment basin south of Monument
Road (see Section 3.2.3) could reduce
maintenance needs in Smuggler’s
Gulch north
Summary of Sediment Characteristics
Particle Size
(approximate)
Smugglers: 15–70%
sand, 30–85% fines;
Pilot: 70–80% sand,
20–30% fines (varies
seasonally and by location)
Color Light gray to pale
yellow, olive,
micaceous
Contaminants No hazardous waste
Trash Rating Very High
See Appendix A for additional detail and
references
Upstream increases in erosion have resulted
in excessive deposition of sediment where
flow velocities decrease in the flatter channels
of the Valley such as Smuggler’s Gulch and
Pilot Channel.

Location of Smuggler’s Gulch North
of Monument Road and Pilot Channel
Smuggler’s Gulch Before and After
Maintenance (City of San Diego 2009)

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SEDIMENT SOURCE Smuggler’s Gulch South of Monument Road

3.2.3 Smuggler’s Gulch South
of Monument Road
Location Smuggler’s Gulch is a
tributary to the mainstem Tijuana
River in the vicinity of Monument
Road and Hollister Avenue
Ownership County of San Diego
Type of Source Managed natural
channel and potential constructed
sediment basin
Size 0.17-mile-long channel segment,
plus 4.7-acre proposed basin area
(County of San Diego 2021)
Estimated Annual Sediment
Yield Historically, 8,000–10,000
cubic yards from channel
Maintenance Historically, twice
per year in channel
Other Considerations A
Smuggler’s Gulch sediment basin
upstream of Monument Road has
been proposed as part of the
improvements under Senate Bill
507 to address the negative
impacts of transboundary flows
Summary of Sediment Characteristics
Particle Size
(approximate)
Smugglers: 15-70%
sand, 30–85% fines
(varies seasonally and by
location)
Color Light gray to pale
yellow, olive,
micaceous
Contaminants No hazardous waste
Trash Rating Very High
See Appendix A for additional detail and
references
Smuggler’s Gulch South of Monument
Road, Looking Upstream Away from Road
(Coastal Consevancy 2021)
Location of Smuggler’s Gulch South
of Monument Road
This erosional area threatens to undermine
infrastructure at Monument Road. A proposed
sediment basin could improve site conditions
and trap sediment that typically accumulates in
Smuggler’s Gulch and areas downstream.

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Tijuana River Main Channel
(Flood Control Channel to
Dairy Mart Road)

SEDIMENT SOURCE
Location Mainstem of the Tijuana
River downstream of the
international border to the Dairy
Mart Road Bridge
Ownership International
Boundary and Water Commission
Type of Source
Constructed/altered channel
and floodplain
Size 1.7 miles long
Estimated Annual Sediment
Yield Estimates range from 3,400 -
–15,000 cubic yards (note: 109,000
cy sediment existing –
approximately 1.7M cy sediment
and trash existing)
Maintenance Periodic
Other Considerations
Development of in-channel and
off-channel sediment basins have
been evaluated

3.2.4 Tijuana River Main Channel
(Flood Control Channel to
Dairy Mart Road)
Constructed in 1977, this area was designed by
the U.S. Army Corps of Engineers (USACE) for
flood control and is bound by levees on the
north and south, creating a floodplain where
sediment deposits.

Summary of Sediment Characteristics
Particle Size
(approximate)
40–70% sand,
30–60% fines (varies
seasonally and by location)
Color Olive gray to light
olive gray,
micaceous
Contaminants No hazardous waste
Trash Rating Low
See Appendix A for additional detail
and references
Location of Tijuana
River Main Channel
Tijuana River Main Channel (USACE 2020)

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Brown Fill Area

3.2.5 Brown Fill Area

SEDIMENT SOURCE
Location Part of a horse ranch
immediately south of the San Diego
Park Department ranger station,
north of the Tijuana River, and west
of the Hollister Street Bridge
Ownership Private property
Type of Source Constructed fill
Size Approximately 4.2 acres
Estimated Annual Sediment
Yield 16,000–35,000 cubic yards
(one-time removal)
Maintenance One-time removal;
will require processing to remove
trash/debris
Other Considerations The
California Integrated Waste
Management Board conducted a
study of the fill and determined it
to be non-hazardous but with large
debris and trash. Quantity of
sediment may be a limiting factor
for re-use opportunities.

Summary of Sediment Characteristics
Particle Size 17–70% sand,
30–83% fines (varies
by location)
Color No data
Contaminants No hazardous waste
Trash Rating Low1
See Appendix A for additional detail
and references
1 Trash Rating based on surface observation only.

Brown Fill is known to contain significant
trash/debris.

Potential upland source where private
property owners placed 16,000 cubic yards of
fill on the riverbank following a flood in 1980.

Subsequent flooding in 1993 caused major
damage that was largely attributed to the fill.

Location of Brown Fill
Brown Fill Area, Looking South at the
Manufactured Fill (USACE 2018)

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SEDIMENT SOURCE Tijuana River Estuary

3.2.6 Tijuana River Estuary
Location Terminus of the Tijuana
River at the Pacific Ocean, within
the Tijuana Slough National
Wildlife Refuge and Border Field
State Park
Ownership California State Parks
and U.S. Fish and Wildlife Service
(USFWS)
Type of Source Natural area
Size 1,072 acres (USFWS)
Estimated Annual Sediment
Yield No data
Maintenance Periodic dredging/
maintenance of the river mouth
Other Considerations The Estuary
is impacted by both watershed
and littoral processes, and
supports sensitive habitat; current
Estuary dynamics/ management
result in sediment deposition
within the estuary and a deficit
offshore
Summary of Sediment Characteristics
Particle Size
(approximate)
40–60% sand,
40–60% fines (varies
by location)
Color Light gray, olive
gray, pale olive
Contaminants No hazardous waste
Trash Rating No rating; listed as
impaired for trash
See Appendix A for additional detail and
references
Constructed in 1977, this area was designed
by USACE for flood control and is bound by
levees on the north and south, creating a
floodplain where sediment deposits.

Location of Tijuana River Estuary
Looking West at the Tijuana River Estuary
from a High Vantage Point (USACE 2020)

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3.3 Sediment Sources in Mexico
A suite of sediment basins exists in the upper TRW in
Mexico and should be considered in sediment
management planning for the region (Figure 3-2).

There are 24 known sediment basins ranging in
capacity from 200 cy to 13,000 cy. Combined, the
basins have approximately 100,000 cy capacity for
holding sediment.

Additional considerations for utilization of sediment
sources in Mexico include binational collaboration,
potential use of Mexico-based contractors and
laboratories, and cross-border transport.

Mexico sediment basins in the TRW should be considered in sediment management planning.

Figure 3-2: Sediment Basins in the Upper Tijuana River Watershed

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INTENTIONALLY LEFT BLANK

SECTION 4
Sediment Management Components
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4 Sediment Management Components
Watershed systems include areas of sediment
deposition as part of natural processes, including
large flow events and altered flow regimes from
anthropogenic activities and infrastructure. In both
natural areas and managed basins, periodic
management to maintain flow conveyance, remove
accumulated sediment and trash, protect
downstream habitat, and reduce flood risk is often
needed. Management activities generally include
handling and sorting, characterization, and transport
for beneficial reuse or disposal. This section
describes sediment management components in the
following categories (Figure 4-1):

1. Excavation/dredging

2. Staging and storage

3. Processing (dewatering, screening,
separation, debris removal,
contaminant stabilization)

4. Sediment characterization and testing

5. Transport

6. Beneficial reuse or disposal
Sediment management details are described below.

Figure 4-1: Sediment Management Process

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4.1 Excavation/Dredging
Excavation from engineered sediment basins and
natural deposition areas is typically performed in dry
conditions using earthmoving equipment such as
excavators, loaders, and bulldozers. During
excavation and maintenance activities, it may also be
necessary to remove waste tires and debris captured
by debris barriers (e.g., trash booms) if present.

Typically, excavators remove material from the basin
or channel. Loaders move sediment onto trucks for
transportation to a processing pad. The excavation
process often requires repeat use of short-distance
haul routes. Excavation equipment access areas and
haul routes require careful planning to optimize
efficiency and minimize impacts to habitat.

In wet conditions, dredging activities are used to
maintain river channels, estuary areas, bays, and
inlets. Inundation conditions, material, and disposal
options are factors that affect the selection of
appropriate dredging methods for a particular site.

Hydraulic dredging involves removal of sediment
using a floating dredge and discharge pipeline to
relocate material. This method is generally
applicable to locations where the disposal site is
within approximately 1 mile of the dredging site.

Booster pumps or transport scows may be used to
transport hydraulically dredged material longer
distances. Recent work at San Elijo Lagoon
included pumping of sand for 3 miles from source
location to discharge site using two booster pumps
spaced at intervals of 1 mile. Booster pumps do not
work well in cobble or stony environments because
the rocks/cobbles can damage the equipment.

Mechanical dredging uses heavy equipment
operating from a barge or from shore and is better
suited for certain types of material. This method often captures a greater proportion of sediment to water
and lessens the need for dewatering during material
processing. Mechanical dredging types include
clamshell, excavator, and amphibious dredges.
• A clamshell dredge consists of a bargemounted crane outfitted with a clamshell bucket for excavation and is suitable for
excavating all types of material except for
solid rock.
• An excavator dredge consists of a bargemounted hydraulic excavator. Excavator dredges are used when the characteristics
of the dredge site limit clamshell dredge
cost-efficiency. The excavator dredge is
especially suited for excavating
hard materials.
• Amphibious excavators are specialty
equipment for environments that are both
wet and dry. Certain areas of the Tijuana
River Estuary may require use of an
amphibious excavator.

Site-specific conditions and project goals will
dictate excavation or dredge method application
within the TRW.

Excavation equipment access areas and haul routes are carefully planned to optimize efficiency and minimize impacts to habitat.

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4.2 Staging and Storage
Staging and storage areas are used to manage and
temporarily store sediment as part of operational
activities. Sediment derived from riverine and
estuarine systems is almost certain to require some
form of processing (described in Section 4.4) to
separate rock, sand, and debris.

A staging and storage area is ideally located on
previously disturbed native dirt that would allow
earthmoving and other processing equipment to safely
operate. The area needs to be sized appropriately to
accommodate sediment stockpiles, processing
operations, equipment storage, stormwater pollution
prevention best management practices, and employee
parking if necessary. Access to the area for off-site
transportation of processed sediment must be
sufficient to accommodate dump trucks and other
large earthmoving equipment.

As part of the sediment staging process, short-term
storage may also be necessary. Sediment stockpiles
are stored in large piles sized according to staging area configuration, equipment capability, processing stage,
and expected storage duration. Storage also allows for
aeration and UV-exposure to reduce potential
contaminants such as fecal coliform bacteria. For
longer durations stockpiles, visqueen covering is used
to prevent stormwater and wind erosion. Staging areas
may also temporarily stockpile segregated trash,
debris, and tires prior to legal disposal.

Additionally, certain beneficial reuse and disposal
alternatives may be subject to extended permitting or
funding timelines. Accordingly, storage area capacity
and permitting parameters may be limiting factors for
some sediment management activities.

Examples of sediment and debris stockpiles.

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4.3 Sediment Characterization
and Testing
The requirements and methods for sediment
characterization and testing are selected based on
the potential reuse opportunities or disposal options.

Sampling collection follows the procedures
explained in the USPEA’s Methods for Collection,
Storage, and Manipulation of Sediments for
Chemical and Toxicological Analyses: Technical
Manual (EPA 2001). Analysis methods are
summarized in Table 4.1. A list of analytes to test for in sediment samples is provided in the Tijuana River
Valley Sediment Management Plan and Monitoring
Program (City of Imperial Beach 2021).

Table 4-1. Sediment Management Pathway Types and Testing Criteria Sediment Management Pathway Type Applicable Testing Criteria Beneficial Reuse Beach and Nearshore Nourishment SCOUP
Thin-layer Sediment Addition CCR Title 22 and SCOUP1
Levee Rehabilitation CCR Title 22
Construction and Landscape
Material
CCR Title 22
Mine Reclamation SCOUP1
Disposal Upland Landfill Disposal and Daily
Cover
CCR Title 22, Waste Acceptance
Guidelines
Notes:

SCOUP = Sand Compatibility and Opportunistic Use Program Plan 1 Potential reuse for thin-layer sediment addition and mine reclamation do not have an associated testing criterion. The listed criteria above are being used as a conservative basis for determining reuse potential.

Any proposed beach and nearshore nourishment
project will require characterization and testing
following the general guidelines of the Inland Testing
Manual (USACE and EPA 1998) and documentation
with a sampling and analysis plan. The sampling and
analysis plan will outline the sediment characterization and testing approach pursuant to the Inland Testing
Manual, and will include critical analyses such as
physical grain size testing and chemical testing for
potential contamination of the source material, and
potentially physical testing of the receiver site. A good reference is San Diego Association of Government’s
Final Sand Compatibility and Opportunistic Use
Program Plan (SCOUP), which describes the required
sediment characterization and testing required for
beach and nearshore nourishment (SANDAG 2006).

For sediment characterization and testing of
construction and landscape material, levee
rehabilitation and upland landfill disposal and
daily cover; Title 22 of the California Code of
Regulations (CCR Title 22) is required. Waste
Acceptance Guidelines are additional
requirements for landfill disposal (City of
Imperial Beach 2021).

Sediment characterization and testing for mine
reclamation and thin-layer sediment addition do not
have mandatory criterion. A conservative
assumption for these beneficial reuse options is to
use the methods from CCR Title 22 and SCOUP for
thin-layer sediment addition and SCOUP for mine
reclamation (City of Imperial Beach 2021).

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4.4 Processing
As part of the sediment management process,
material may require processing methods such as
screening, dewatering, and stabilization to prepare it
for beneficial reuse or certain types of disposal. Gross debris (e.g., tires and other large objects) are
generally removed in early stages of processing.

Sediment screening is used to sort/segregate
relatively finer material (sand/silt/clay) more
suitable for an estuary and beach from coarser
material (cobble/rock). Sifters are used to filter
trash, stones, and cobble from finer material.

Subsequent finer-level mechanical screening to
remove trash, debris, and plastics is anticipated to
be necessary for most applications of beneficial
reuse and disposal.

Material dewatering is only likely to be employed for
mechanically dredged material to reduce the effort
required to handle and transport material. Dewatering
refers to the separation of water from dredged
material. Dewatering is preferred to occur at the site
of dredging if water quality management processes
allow. The water is typically returned to the
environment unless treatment and disposal is
required due to contamination concerns. Dewatering
is especially likely for management alternatives
involving upland reuse such as incorporation as
construction material. Dewatering may also be able to
occur at the processing pad if sufficient runoff control measures can be implemented.

Depending upon the level of contamination
determined to be present within the material,
stabilization/solidification (S/S) may be required for
certain disposal alternatives. S/S is a soil remediation process by which contaminants are rendered
immobile through reactions with additives or
processes. Stabilization is the general term for a
process that transforms contaminants into a less
mobile or toxic form. The process could take the form
of mixing contaminated sediments with fixative
agents such as fly-ash or special grout mixtures to
render the sediments inert, or thermal treatments to
remove broad spectrum contaminants. Solidification
is a more specific process that treats material to
increase its solidity and structural integrity.

Solidification does not remove or degrade
contaminants but prevents their transport by
eliminating or significantly hindering their mobility.

This process is also referred to as immobilization,
fixation, or encapsulation. Contaminants may be
chemically bound or encapsulated into a matrix
during this process. The S/S process accomplishes
one or more of the following:

1. Improved handling and physical
characteristics of sediment

2. Decreased surface area of the sediment
mass through which transfer/contaminant
leakage can occur

3. Limited solubility of hazardous constituents
in the waste
However, the S/S process is a potentially
significant additional cost due to the added need
for materials and handling. Therefore, reuse and
disposal options that do not require S/S processing
are often preferred.

Microplastics are an emerging environmental concern
with sediment processing implications (Brander et al.
2021). Microplastics are defined in California as
plastic particles less than 5 millimeters in length.

Current technical and operational capabilities limit
options for feasible and cost-efficient processing
steps to sift particles that meet the microplastic
definition. Ongoing multi-disciplinary work is needed
to support microplastic reduction efforts statewide.

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4.5 Transport
Once processed, sediment is typically transported to
beneficial reuse or disposal sites via truck. Dry,
processed material is transported using single or
double dump trucks, in 7 and 14 cy volumes.

Trucking operations require a suite of best
management practices to limit air quality,
stormwater, and roadway-related impacts. Examples
include tracking controls, load coverings, and
operations hours limitations to accommodate local
traffic demands.

Sediment transport via pipeline may be an option for
certain locations and beneficial reuse options.

Hydraulic dredging operations conducted at certain
locations may transport sediment slurry material to
the beach or nearshore ocean using a dredge
pipeline. Dredge pipelines are typically 6 to 10 inches in diameter but may be as large as 36 inches in
diameter. Booster pumps may be required if the
pumping distance exceeds 1 mile. Pipe and booster
pump placement may be constrained by habitat and
sensitive fauna receptors in natural areas. Noise
protection such as housing, shrouds, or similar items
to reduce impacts may be required.

To facilitate deposition of sediment out of the slurry, earthmoving equipment would be used to build
training dikes on the beach, allowing sand-sized
suspended sediment to settle on the beach, as was
performed in Imperial Beach during Regional Beach
Sand Projects I and II, while fines remain suspended
and disperse offshore. Training dikes would be
longitudinal sand berms that direct slurry along and
parallel to the beach at a shallow slope, slowing
slurry flow to the point where suspended sandy
sediment can fall out and accumulate as a beach
berm while fine sediment entrained in water runs off
into the ocean.

A conveyor belt system is also a potential option for
transport of sediment over short, approximately

0.5-mile distances. Conveyor belt systems are
typically used for moving a high volume of sediment
and require significant infrastructure. Additional
considerations include right-of-way issues, roadway
safety if placed next to a road, noise, energy
requirements, and cost.

Sediment transported to beneficual reuse or disposal via truck requires best management practices including tracking controls, load coverings, and limited operational hours.

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4.6 Beneficial Reuse
or Disposal
Excavated and processed sediment is transported to
a beneficial reuse or disposal site. Types of beneficial reuse and disposal are described in the following
section, along with relevant sediment requirements,
example projects and cost considerations.

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SECTION 5
Sediment Management Activities/Pathways
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5 Sediment Management Activities/Pathways
Coastal sediment can provide many beneficial uses for wildlife and humans. Clean sand and gravel provide wildlife habitat within streams and beaches. Sand also provides recreational beach space and access, as well as improves shoreline protection and coastal resiliency to sea level rise. Silt and clay derived from river substrates supply needed nutrients for nearshore habitats. Combinations of these materials can be used by the construction industry for infrastructure development. Easy access to this important construction material has been a factor in California’s economic growth. This section describes potential beneficial reuse pathways for source areas in the Tijuana River Valley, including beach and nearshore nourishment, thin layer sediment addition, levee rehabilitation, construction and landscape material, mine reclamation, and upland landfill disposal. For any pathway requiring mitigation, there is an opportunity for estuary restoration.

Multi-variate considerations and site-specific conditions impact the feasibility and cost-efficiency of potential beneficial reuse and disposal options available for Valley sediment sources. Key elements include sediment composition and contaminant characterization information, environmental and constructability considerations, and source volume, distance to beneficial reuse location, and timing factors. Each of these elements independently and/or collectively impact site-specific decision-making for specific reuse or disposal options.

Table 5-1 provides an overview of key beneficial reuse and disposal mechanisms available for Valley sediment sources. Each pathway is further discussed in the sections below.

Multi-variate considerations and site-specific conditions impact the feasibility and cost-efficiency of potential beneficial reuse and disposal options.

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Table 5-1. Sediment Management Alternatives Summary
Activity Composition Contaminants
Environmental
Considerations
Constructability
Considerations Transport Considerations Volume Timing Cost 1 Dune, Beach, and
Nearshore
Nourishment
Generally sand with
limited fines up to 25%;
Higher percentage fines
material may be viable in
certain conditions
Material needs to be free
from trash, plastics,
hazardous substances (i.e.,
heavy metals and
petroleum), fecal coliform
bacteria; Potential
microplastics considerations
Improves beach profile,
may provide limited sea
level rise mitigation
Potential for improved
nearshore habitat
Conventional land-based
equipment
Truck transport costs
may limit receiver site
locations; Potential for
pipeline transport in
certain conditions
Approximately 50,000 cy
to 250,000 cy per
placement event
Wet season (fall and
winter)
$20–$30 per cy
-Dune enhancement
anticipated to include
additional costs
Thin-Layer Sediment
Addition2
Silts and clays to coarse
sand
Material needs to be free
from trash, plastics,
hazardous substances (i.e.,
heavy metals and
petroleum), fecal coliform
bacteria; Potential
microplastics considerations
Habitat improvement,
improved tidal
hydrology and
circulation, and
increased resilience to
sea level rise
Conventional dredging
equipment and
dredge/hydraulic jetting
device
Local applications only;
off-site transport cost
prohibitive
Approximately 3,000 cy
per acre filled
Biological work windows
limited to September 15-
February 15 (i.e., outside
breeding season for
endangered birds)
Approximately $30 to
$40 per cy; Sitespecific conditions may
impact costs
Levee Rehabilitation Fines and sand
Cobble and rock may be
used as riprap
Material needs to be free
from trash, plastics,
hazardous substances (i.e.,
heavy metals and
petroleum), fecal coliform
bacteria
Improved flood
protection
Conventional land-based
equipment
Geotechnical constraints
Local applications only;
off-site transport cost
prohibitive
Unknown; likely limited
material needed
Potential constraints
associated with adjacent
sensitive habitat
Approximately $30 to
$50 per cy; Sitespecific conditions may
impact costs
Construction and
Landscape Material
Must meet geotechnical
engineering and soil
properties of project or
product
Material needs to be free
from trash, plastics,
hazardous substances (i.e.,
heavy metals and
petroleum), fecal coliform
bacteria
Transport distance may
have ancillary impacts
Conventional land-based
equipment
Geotechnical constraintsmaterial must meet
project-specific criteria
Truck transport costs
may limit receiver site
locations
Variable; depends on
receiver site project need
On the order of 10,000 cy
Potential daily transport
timing limitations
Potentially cost neutral
Mine Reclamation Fines, sands, cobble, rock Material needs to be free from trash, plastics,
hazardous substances (i.e.,
heavy metals and petroleum),
fecal coliform bacteria
SPLP testing may be
required by RWQCB3
Potential for habitat
restoration
Conventional land-based
equipment
Truck transport costs
may limit receiver site
locations
Approximately 1 million cy No restrictions/
constraints
$25 to $35 per cubic
yard
Commercial Landfill
(Landfill Daily Cover)
Fines, sands, cobble, rock Screen material to separate
trash and sediment
Meet individual landfill
WDRs and the Integrated
Waste Management Board
regulations (CalEPA)3
Potential testing required--
RWQCB WET or STLC3
Limited direct
environmental benefits;
Indirect benefits include
reuse of excavated
material
Conventional land-based
equipment
Truck transport costs
may limit receiver site
locations
Approximately 80–120 cy
per day (contact the
landfill for capacity)
Potential daily transport
timing limitations
$65 to $90 per cubic
yard
Notes: cy = cubic yard; RWQCB = Regional Water Quality Control Board; CalEPA = California Environmental Protection Agency; WDR = Waste Discharge Requirement 1 Cost information based on available/historical data predating the COVID-19 pandemic. 2 Although thin layer sediment addition is a potential option for some estuaries, a number of regulatory and stakeholder decisions are required for this to be a viable option. 3 LACSTF 2005.

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5.1 Dune, Beach,
and Nearshore
Nourishment
BENEFICIAL RE-USE AND DISPOSAL What is Dune, Beach, and Nearshore Nourishment? Definition: The placement of appropriate material to restore the historical beach dune system, onto the beach, or in the nearshore environment either in or just outside the surf zone. Potential recurring nourishment for these environments can each improve complexity and heterogeneity of beach-dune habitats.

Goal: Improvem habitat and support the sediment transport withing the littoral cell and increase the volume of sediment with the littoral zone.

Excavating • Processing • Transporting • Placing  $20/cy - $30/cy » Does not include mobilization/demobilization
of excavation/dredging and transportation
equipment, any extraneous costs such as
remediation, contractor markup, and contingency,
material characterization, and post placement
sediment and dune community monitoring.
» Sediment testing and treatment are separate
costs that can greatly vary depending on the
different tests/treatments that are required and
can be cost-prohibitive.

Example Project
Tijuana Estuary Fine Sediment Fate
and Transport Demonstration Project
COST
» Placed over 40,000 cy of material obtained from
the Goat Canyon sediment basins at the waterline
at low tide south of the river mouth.
» Material contained a high percentage of fine
sediment consisting of silt and clay
(approximately 40%).
» Material was excavated from the basins, stockpiled
at a nearby processing pad, sorted for trash and
debris, tested for grain size and chemistry, and
trucked to and placed in the intertidal zone south
of the Tijuana River mouth.
» Environmental conditions showed temporarily
elevated ocean turbidity but rapid dispersion
with no permanent impacts, and no significant
levels of seabed burial of nearshore and offshore
habitat areas.

Typical Project Summary
Volume 50,000 cy to 250,000 cy per placement
Timing Wet Season (fall and winter)
Cost $20-$30 per cy
*Cost information based on available/historical
data predating the COVID-19 pandemic.
**Dune enhancement anticipated to include
additional costs
Appropriate Sediment Characteristics
Location Near source by truck, may be able to transit
further by barge/hopper dredge
Composition Sand with limited fines up to 25
Color Similar color to beach is preferred
Contaminants Material needs to be free from hazardous
substances (i.e., heavy metals and petroleum),
fecal coliform bacteria; Potential microplastics
considerations
Trash Must be removed
Environmental Constructability Distance
Improves beach
profile, may
provide limited
sea level rise
mitigation.

Potential for
improved
nearshore.

Conventional
land-based
equipment.

Truck transport
costs may limit
receiver site
locations.

Potential for
pipeline transport
in certain
conditions.

Considerations
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5.2 Thin Layer
Sediment
Addition (TLSA)

BENEFICIAL RE-USE AND DISPOSAL
What is Thin Layer Sediment Addition?
Definition: Practice of raising the marsh platform to extend its functional lifespan. Opportunity for beneficial use of dredged material could be to apply dredged material in thin layers to sediment-starved coastal marsh areas within the estuary.

Benefits: Enhance wetland longevity, promote continued vegetation growth during SLR, protect against sediment loss, and raising the marsh plain to counteract the effects of SLR. While TLSA is a potential option for some estuaries, a number of regulatory and stakeholder decisions are required for this to be a viable option.

Excavating • Processing • Transporting • Placing  $30/cy - $40/cy » Does not include mobilization/demobilization
of excavation/dredging and transportation
equipment, any extraneous costs such as
remediation, contractor markup, and contingency,
material characterization, and post placement
sediment monitoring.
» Sediment testing and treatment are separate
costs that can greatly vary depending on the
different tests/treatments that are required.
» To assess the cost of TLSA it is important to
consider the type of dredge, area-specific
dredging requirements, and placement/
grooming of the material.

Example Project
Seal Beach National
Wildlife Refuge Augmentation
COST
» TLSA was performed to improve tidal hydrology
and wetland quality.
» Fine material from the routine maintenance
dredging of a nearby harbor was hydraulically
pumped to the project site and aerially sprayed to
achieve target elevation gains.
» Hay bales secured with rebar with natural bindings
were used for containment of slurry material.

Sandbags and geotextile fabric were used to
supplement containment in locations where loss
was occurring.
» The application thickness was measured twomonths post-placement and found to be an average of 8.5 inches.
» Following completion of the project, monitoring
showed that vegetation was naturally recovering in
patches (Garvey and Brodeur 2016).

Typical Project Summary
Volume 3,000 cy per acre filled
Timing Biological work window; limited to Sept 15
- Feb 15 (i.e. outside of breeding season for
endangered birds)
Cost $30-$40 per cy, site-specific conditions
impact costs
*Cost information based on available/historical
data predating the COVID-19 pandemic.

Appropriate Sediment Characteristics
Location Near source
Composition Sand and fines
Color Any
Contaminants Material needs to be free from hazardous
substances (i.e., heavy metals and petroleum),
fecal coliform bacteria; Potential microplastics
considerations
Trash Must be removed
Environmental Constructability Distance
Habitat
improvement,
improved tidal
hydrology and
circulation,
and increased
resilience to sea
level rise.

Conventional
dredging
equipment and
dredge hydraulic
jetting device.

Local application
only—offsite
transport cost
prohibitive.

Considerations
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5.3 Levee
Rehabilitation
BENEFICIAL RE-USE AND DISPOSAL What is Levee Rehabilitation? Definition: Dredge material used to rehabilitate levees, also called dikes.

Benefits: The material may be used as a stabilizing berm to prevent slope failure due to liquefaction from earthquakes or oversteepening of the slope from erosion of weak soils. Additionally, material placement atop levees could help protect against sea level rise.

Excavating • Processing • Transporting • Placing  $30/cy - $50/cy » Does not include mobilization/demobilization
of excavation/dredging and transportation
equipment, any extraneous costs such as
remediation, contractor markup, and contingency,
material characterization, and post placement
sediment monitoring.
» Sediment testing and treatment are separate
costs that can greatly vary depending on the
different tests/treatments that are required.
» The excavation and transport of sediment for
levee rehabilitation is essentially the same as that
for beach nourishment.

Example Project
Sacramento-San Joaquin Delta
COST
» In Northern California, weak soils, such as a silt/clay mix or peat, are characteristic along the bay shore
of the Sacramento-San Joaquin Delta.
» If the bay-side of the dike erodes, combined with
the weak soil, the slope failure safety factor for
the dike is greatly reduced. This can lead to high
structural fragility of the dikes.
» When protected habitat exists on the bay-side
of the dike, reestablishing a reasonable slope is
unacceptable. In these instances, dredged material
has been placed on the landward side of dikes
in the Sacramento-San Joaquin Delta to act as
a stabilizing berm against static or earthquake
loading (CCSMW 2017).

Typical Project Summary
Volume Unknown; likely limited material needed
Timing Potential constraints associated with adjacent
sensitive habitat
Cost $30-$50 per cy, site-specific conditions
impact costs
*Cost information based on available/historical
data predating the COVID-19 pandemic.

Appropriate Sediment Characteristics
Location Near source
Composition Fines and sand; cobble and rock maybe used
as riprap. Must meet geotechnical engineering
properties of the levee location.

Color Any
Contaminants Material needs to be free from hazardous
substances (i.e., heavy metals and petroleum),
fecal coliform bacteria. Treated material
accepted.

Trash Must be removed
Environmental Constructability Distance
Improved flood
protection.

Conventional
land-based
equipment
Geotechnical
constraints -
material must
meet USACE
standards.

Local application
only—offsite
transport cost
prohibitive.

Considerations
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5.4 Construction
and Landscape
Material
BENEFICIAL RE-USE AND DISPOSAL What is Construction and Landscape Material? Definition: Use of excavated or dredged sediments in production of construction material. Some material types are a viable end-product for contaminated material and potentially require lower standard of treatment.

Benefits: Using both clean and contaminated dredge material as a construction product is achievable with dewatering. Material must meet geotechnical engineering properties and sediment cannot exceed criteria set by RWQCB for chloride leaching to prevent groundwater contamination (LACSTF 2005).

Excavating • Processing • Transporting • Placing  $46/m3 in 2005 » Does not include mobilization/demobilization
of excavation/dredging and transportation
equipment, any extraneous costs such as
remediation, contractor markup, and contingency,
material characterization, and post placement
sediment monitoring.
» Sediment testing and treatment are separate
costs that can greatly vary depending on the
different tests/treatments that are required.

Example Project
Goat Canyon Sediment Basins
COST
» Sediment excavated from the Goat Canyon
sediment basins is re-used as base material at
a local landscape nursery to blend with mulch
and plant debris to create soil amendment. Final
products are used for landscape applications.
» A single nursery equipped with the proper
processing equipment and methods can accept
approximately 10,000 cy annually (Evans, pers.
comm. 2022).
» A local concrete and asphalt supplier may use
as base material to blend with other materials to
create commercially acceptable products for use in
pavement and other hardscape materials. Annual
amount they can accept (single supplier equipped
with proper processing equipment and methods) is
approximately 10,000 cy.

Typical Project Summary
Volume Variable; on the order of 10,000 cy
Timing Potential daily transport timing limitations
Cost Potentially cost neutral
*Cost information based on available/historical
data predating the COVID-19 pandemic
Appropriate Sediment Characteristics
Location Near source
Composition Dependent on required geotechnical
engineering properties for the construction
project or soil properties required by the
product
Color Any
Contaminants Accepted depending on the type of project
and if the contaminants can be isolated from
the environment
Trash Must be removed
Environmental Constructability Distance
Transport distance
may have ancillary
impacts.

Conventional
land-based
equipment.

Geotechnical
constraints -
material must
meet projectspecific criteria.

Truck transport
costs may limit
receiver site
locations.

Considerations
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5.5 Mine
Reclamation
BENEFICIAL RE-USE AND DISPOSAL What is Mine Reclamation? Definition: Recovery of a mine or quarry at the end of its life. Usually the equipment is dismantled, any hazardous waste is removed or mitigated and the remaining pit where the raw materials were extracted is regraded.

The final project may be left as open space, reclaimed to habitat or developed into agriculture or residential/commercial areas.

Benefits: Dredged or excavated sediment may be re-used as a component of the manufactured fill and topsoil (CDPR 2021).

Excavating • Processing • Transporting • Placing  $25/cy-$35/cy » Does not include mobilization/demobilization
of excavation/dredging and transportation
equipment, any extraneous costs such as
remediation, contractor markup, and contingency,
material characterization, and post placement
sediment monitoring.
» Sediment testing and treatment are separate
costs that can greatly vary depending on the
different tests/treatments that are required.

Example Project
Nelson Sloan Quarry Restoration and
Beneficial Reuse of Sediment Project
COST
» Project beneficially re-uses sediment for the
purpose of landform and habitat restoration.
» Sediment is derived from several on-going and
proposed sediment management activities
including sediment basins (e.g., Goat Canyon),
flood control facilities and conveyances, and habitat
restoration and enhancement projects.
» Phased approach to restore previously mined
portions of the property to its original grade. A
total of about 1 million cy of fill material may be
beneficially re-used.
» Limited by transportation cost and tipping fees,
which includes the monetary cost of hauling the
sediment to the landfill, truck noise, environmental
effects of the truck exhaust and the effect of
numerous truck trips to the transportation
infrastructure.
» Prior to hauling, the material must be dewatered.
» The landfill permit will require TCLP and STCL
analyses to confirm material may be used for
daily cover.

Typical Project Summary
Volume 1 million cy
Timing No restrictions/constraints
Cost $25 - $35/cy
*Cost information based on available/historical
data predating the COVID-19 pandemic.

Appropriate Sediment Characteristics
Location Near source
Composition Any, manufactured fill needs both silt and sand Color Any
Contaminants Material needs to be free from hazardous
substances (i.e., heavy metals and petroleum),
fecal coliform bacteria. Treated material
accepted.

Trash Must be removed
Environmental Constructability Distance
Landform
and habitat
restoration.

Must be
dewatered first.

Nearby; would be
cost prohibitive
to truck sediment
long distance.

Considerations
March 2023
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Final Tijuana River Sediment Management Plan 5/ Sediment Management Activities/Pathways

5.6 Upland
Landfill
Disposal
BENEFICIAL RE-USE AND DISPOSAL What is Upland Landfill Disposal? Definition: Last resort for dredged material because it can be quite costly.

Consideration include identification of a permitted upland landfill that will accept the sediment, quantity of material, contamination level, debris content and CEQA document inclusion. Excavated and dredged material needs to be completely dewatered before transport to prevent any discharge from the trucks and leaching in the landfill.

Benefits: In contaminated soil conditions, may be the only option.

Excavating • Processing • Transporting • Placing  $65/cy - $90/cy » Does not include mobilization/demobilization
of excavation/dredging and transportation
equipment, any extraneous costs such as
remediation, contractor markup, and contingency,
material characterization, and post placement
sediment monitoring.
» Sediment testing and treatment are separate
costs that can greatly vary depending on the
different tests/treatments that are required.

Example Project
Republic Services Otay Landfill
COST
» California State Parks has recently planned for the
upland landfill disposal of sediment from the Goat
Canyon sediment basins (CSP 2018).
» All material is proposed for landfill disposal,
including sediment, tires, plastics, and trash.

Although all material is targeted for landfill
disposal, the excavated or dredged material is
still anticipated to be screened so that trash and
sediment can be separated.
» The nearest landfill, Republic Services Otay
Landfill, is approximately 10 miles northeast of the
Goat Canyon sediment basins at 1700 Maxwell Rd,
Chula Vista, CA 91911.
» Guidelines and required forms for the Republic
Services landfills in San Diego are provided in
Appendix B.

Typical Project Summary
Volume Approximately 80-120 cy/day (contact the
landfill for capacity)
Timing Potential daily transport timing limitation
Cost $65 - $90/cy
*Cost information based on available/historical
data predating the COVID-19 pandemic
Appropriate Sediment Characteristics
Location Near source
Composition Any
Color Any
Contaminants Screen material to separate trash and
sediment, but all would go to the landfill. Meet
individual landfill WDRs and the Integrated
Waste Management Board regulations
(CalEPA). Potential testing required-RWQCB
WET or STLC.

Trash Accepted
Environmental Constructability Distance
Limited direct
environmental
benefits
Indirect benefits
include reuse
of excavated
material.

Conventional
land-based
equipment.

Truck transport
costs may limit
receiver site
locations.

Considerations
March 2023
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Final Tijuana River Sediment Management Plan 5/ Sediment Management Activities/Pathways

SECTION 6
Regulatory Framework
14010
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6-1
6 Regulatory Framework
Sediment management activities in the Tijuana River
Valley are currently managed as agency-driven ad-hoc
projects performed on a case-by-case basis. Each
project is subject to myriad federal, state, and
regional/local statutes and regulations that govern
dredging, beneficial use and/or disposal. This section
outlines roles of key regulatory agencies and the
project-specific permitting framework for sediment
management beneficial reuse and disposal options.

A regional perspective is needed to coordinate a longterm vision allowing for improved cost-efficiency of sediment management activities within the Tijuana
River Valley. Within the context of the growing interest in California to streamline regulatory processes for
permitting environmental projects (CLSN 2020), this
section outlines anticipated project permits and a
thoughtful permitting strategy to both guide project
proponents and serve as basis for permitting
discussion at a policy level.

6.1 Overview
Multiple federal, state, and regional legislative
statues and regulations govern current and future
sediment management activities in the Valley
(Table 6-1). A glossary of terms, pertinent agencies,
and applicable legislation/regulatory guidelines is
included as Appendix D.

A regional perspective is
needed to coordinate a longterm vision allowing for
improved cost-efficiency of
sediment management
activities within the Tijuana
River Valley.

Projects are subject to myriad federal, state, and regional/ local statutes and regulations that govern dredging, beneficial use and/or disposal in the Valley.

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Table 6-1. Federal, State, and Regional Statutes and Regulations Governing Sediment Management Activities in the Tijuana River Valley Regulatory
Level Agencies Applicable Legislation/Regulatory Guidance Federal U.S. Army Corps of
Engineers
U.S. Fish and Wildlife
Service
U. S. Environmental
Protection Agency
National Oceanic
Atmospheric
Administration
International Boundary
and Water Commission
Clean Water Act of 1977
Rivers and Harbors Act (Section 10)
National Environmental Policy Act of 1969
Marine Protection, Research, and Sanctuaries Act
Coastal Zone Management Act
Fish and Wildlife Coordination Act of 1958
Federal Endangered Species Act of 1973
Migratory Bird Treaty Act
National Historic Preservation Act of 1966
Federal Water Project Recreation Act
Resource Conservation and Recovery Act
Magnuson–Stevens Fishery Conservation and Management Act Federal Antidegradation Policy
State California Coastal
Commission
State Water Resources
Control Board
Regional Water Quality
Control Board (RWQCB)
California Department of
Fish and Wildlife
California State Lands
Commission
California State
Department of Parks and
Recreation
California Coastal Act of 1976
Porter Cologne Water Quality Act
California Ocean Protection Act
California Environmental Quality Act
Construction General Permit
California Endangered Species Act
California Toxics Rule
California Antidegradation Policy
California Fish and Game Code – Sections 1600-1616
Regional RWQCB
County of San Diego
City of San Diego
City of Imperial Beach
National Pollutant Discharge Elimination System Permit and Waste Discharge Requirements for Discharges from the Municipal Separate Storm Sewer Systems Draining the Watersheds within the San Diego; Order R9-2013-0001 – amended by Order Nos. R9-2015-001, and R9-2015-0100.

County of San Diego General Plan
City of San Diego General Plan
Tijuana River Valley Local Coastal Program Land Use Plan and Coastal Development Permit San Diego Multiple Species Conservation Program and Local Incidental Take Permits

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Within this regulatory framework, a suite of agency permits are generally required for sediment management activities. A summary of key permit types and descriptions is presented in Table 6-2.

Table 6-2. Summary of Key Permit Types and Descriptions Agency Permit Type Description
U.S. Army
Corps of
Engineers
(USACE)
Clean Water Act
Section 404 Permit
and Rivers and
Harbors Act
Section 10 Permit
Section 404 of the federal Clean Water Act regulates the discharge of dredged or fill material into waters of the United States. Section 10 of the Rivers and Harbors Act regulates structures and work in or over navigable waters of the United States. For beach nourishment projects and some other reuse activities, compliance involves demonstration that the sediment proposed for placement will not degrade water quality, closely matches the sediment grain size of the receiver beach sediment, contains a minimum quantity of silt and clay, and is free of contaminants. Sediment sampling and testing of the proposed source sediment and the beach receiver site must be performed to demonstrate compatibility; review and approval of the sediment testing program and results is the responsibility of the U.S. Environmental Protection Agency and USACE. Additional requirements include the submittal and implementation of a detailed pre- and post-monitoring report.

U.S. Fish and
Wildlife
Service
(USFWS)/
National
Marine
Fisheries
Service
(NMFS)
Biological Opinion USFWS works collaboratively to consult USACE to evaluate potential federally-listed species impacts through the Endangered Species Act (ESA) Section 7 process to ensure the issuance of a USACE permit (the federal action) would not jeopardize any federally listed species or adversely modify designated critical habitat. The Biological Opinion is used to quantify species impacts and provide conservation recommendations and reasonable and prudent measures to minimize take.

In instances when the USACE permit may affect federally-listed marine species, NMFS conducts Section 7 consultations.

ESA Section 10 Permit In the event a proposed project may result in take of a threatened or endangered species and there is no ESA Section 7 nexus, such as a USACE permit, a Section 10 permit, also known as Incidental Take Permit, is required. The permittee must develop a Habitat Conservation Plan that includes an assessment of the likely impacts on protected species, measures that will be taken to mitigate potential impacts, and an analysis of alternative mitigation efforts. A plan to monitor and manage species and habitat is also required. Typically, the National Environmental Policy Act/California Environmental Quality Act process will identify the potential need for a Habitat Conservation Plan.

In certain instances when federally-listed marine species may be impacted, NMFS administers ESA Section 10 permits.

California
Coastal
Commission
(CCC)
Coastal Development
Permit
The California Coastal Act of 1976 established the statewide program requirement to obtain a state permit for any development or work within the coastal zone so that existing resources and public uses are protected. Applications must demonstrate that the excavation, conveyance, and placement of source sediment at a receiver site complies with a broad spectrum of policies and guidelines that are outlined in the act. Protection of biological resources, preservation of public access, public acceptance of the project proposal, and minimization of temporary or permanent environmental impacts associated with sand placement are the key assessment criteria commonly involved when reviewing beach nourishment projects.

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Table 6-2. Summary of Key Permit Types and Descriptions Agency Permit Type Description
California
Department of
Fish and
Wildlife
(CDFW)
1600-1601
Streambed Alteration
Agreement
A Lake and Streambed Alteration Agreement is required if a project will affect any river, lake, or stream, for example if the receiver site is at or adjacent to an existing river mouth or streambed and may affect that stream.

California Endangered
Species Act (CESA)
Incidental Take
Permit 2081(b)
A CESA Incidental Take Permit 2081(b) is required if there is a likelihood of taking a state listed species. If a species is listed by both the ESA and the CESA, California Fish and Game Code Section 2080.1 allows an applicant who has obtained federal Section 7 consultation or a federal Incidental Take Permit to request that the Director of CDFW find the federal documents consistent with CESA. If the federal documents are found to be consistent with CESA, a consistency determination is issued, and no further authorization or approval is necessary under CESA.

State Water
Resources
Control Board
General Permit for
Discharges of Storm
Water Associated with
Construction Activity
(Construction General
Permit)
Projects that disturb one or more acres of soil or disturb less than one acre are required to obtain coverage under the Construction General Permit. Construction activity subject to this permit includes clearing, grading and disturbances to the ground such as stockpiling, or excavation.

A stormwater pollution prevention plan containing site maps, best management practices, and visual and chemical monitoring programs is required.

Regional
Water Quality
Control Board,
San Diego
Region
Section 401
Certification and
Waste Discharge
Requirements (WDRs)
Enrollment
A Clean Water Act Section 401 water quality certification is required for any federal actions, including USACE permit actions, that may result in any discharge into waters of the United States. The project must be reviewed to ensure that the proposed discharge will comply with applicable state water quality standards. Limitations on turbidity and sediment toxicity are the primary criteria for assessment in the Tijuana River watershed.

WDR encompass all discharges that “could affect the quality of the state.” WDR are required pursuant to the Porter-Cologne Water Quality Control Act for projects that propose to discharge into waters of the state. Requirements are created by considering beneficial uses to be protected, water quality objectives, other waste discharges in the water body, the need to prevent nuisance, and economic considerations.

California
State Parks
Encroachment Permit An Encroachment Permit will be required if the receiver site is located within a State Park or State Beach, or if access across state property is necessary for project implementation. This program could also require a special use permit or right of entry permit.

California
State Lands
Commission
Lease of State Lands A Lease of State Lands is necessary for any work occurring below the mean high tide line. Prior to placement of sand below the mean high tide line a mean high tide line survey is required. Additional surveys may be required every few years for long-term programs. Supplemental maps and CAD drawing files of the survey may also be required.

Applicable
Local
Jurisdiction
Grading Permit A grading permit is required for any grading, public right-of-way improvement, construction changes to an existing grading or public improvement permit, site reconnaissance and testing, and asgraded soils reports within City jurisdiction.

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Table 6-2. Summary of Key Permit Types and Descriptions Agency Permit Type Description
Applicable
Local
Jurisdiction
Coastal Development
Permit
For development within the coastal zone of a city or county with a certified Local Coastal Program (LCP), a coastal development permit must be obtained using the LCP as the standard of review. LCP policies normally mirror those of the California Coastal Act in terms of impact avoidance to biological resources, public access, and environmental conditions. In the event that a single project straddles multiple local and/or CCC permitting jurisdictions, CCC may issue a single consolidated Coastal Development Permit for the entire project.

Notes: ESA = federal Endangered Species Act; CDFW = California Department of Fish and Wildlife; CCC = California Coastal Commission.

6.2 Applicable Permits to
Relevant Sediment Source
Locations and Pathways
Within the complex multi-agency regulatory
framework, project-specific permitting pathways can
be challenging to delineate, costly to navigate, and
require extensive lead times. Key factors in permit
application preparation and agency review include
project location and description, sediment
characterization information, biological and historical resources both within and adjacent to the project site, and potential short- and long-term project impacts
associated with implementation. A summary of key
potential permitting elements for Valley sediment
management projects is presented below.

The first element of sediment management is
excavation from the source location. Table 6-3
presents a summary list of applicable permits needed
to remove sediment from the Valley depositional
sites. A key discerning factor for permit applicability for the Valley source locations is whether the
sediment is being removed from within waters of the
United States and within the State Coastal Zone.

The second aspect of sediment management
permitting is proposed sediment beneficial reuse
options and placement locations. Table 6-4 lists
beneficial reuse options and associated anticipated
permit requirements. Similar to the permit strategy for source areas, not all permits apply to each proposed
sediment beneficial reuse option.

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Table 6-3. Probable Permit Requirements for Tijuana River Valley Sediment Source Locations USACE Section 404/10 USFWS/NMFS/CDFW/Local Incidental Take Permit and/or Federal Section7 Consultation CCC/Local Cities Coastal Development Permit CDFW 1600-1601 Streambed Alteration Agreement: CDPR Encroachment Permit: SLC Lease of State Lands RWQCB Section 401 Certification/ WDR enrollment Local Grading
Permit
Tijuana River Main
Channel
*
Pilot Channel *
Brown Fill Area
Smuggler’s Gulch
North of Monument
Road/Pilot Channel
**
Smuggler’s Gulch
South of Monument
Road
**
Goat Canyon
Sediment Basins
Tijuana River Estuary
Notes: = Yes; = No; = Possible.
* Dependent on if excavation site is near least Bell’s vireo habitat. ** Needs both City and County Permits.

USACE = U.S. Army Corps of Engineers; USFWS = U.S. Fish and Wildlife Service; NMFS = National Marine Fisheries Service; CDFW = California Department of Fish and Wildlife; CCC = California Coastal Commission; CDPR = California Department of Parks and Recreation; SLC = State Lands Commission; RWQCB = Regional Water Quality Control Board; WDR = Waste Discharge Requirement

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Table 6-4. Applicable Permits to Relevant Sediment Pathways

USACE
Section
404/10
USFWS/NMFS/CDFW/Local
Incidental Take Permit
and/or Federal §7
Consultation
CCC/Local
Cities
Coastal
Development
Permit
CDFW
Streambed
Alteration
Agreement
CDPR
Encroachment
Permit
SLC
Lease of
State
Lands
RWQCB
Section 401
Certification/
WDR
Enrollment
Local
Grading
Permit Other
Beach and
Nearshore
Nourishment
Thin-Layer
Sediment
Addition
Levee
Rehabilitation
Construction
and
Landscape
Material
Haul
Permit
Landfill Daily
Cover
Haul
Permit
Mine
Reclamation
Haul
Permit
Notes: = Yes; = No; = Possible.
* Port of San Diego has its own permitting process within its jurisdiction.

USACE = U.S. Army Corps of Engineers; USFWS = U.S. Fish and Wildlife Service; NMFS = National Marine Fisheries Service; CDFW = California Department of Fish and Wildlife; CCC = California Coastal Commission; CDPR = California Department of Parks and Recreation; SLC = State Lands Commission; RWQCB = Regional Water Quality Control Board; WDR = Waste Discharge Requirement
The required permits for a particular action can be determined by crosswalking between Tables 6-3 and 6-4. An example scenario may entail removal of sediment from a main Tijuana River source area and placing it in the nearshore environment for beach nourishment. Permit requirements and notes for this scenario are presented in Table 6-5.

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Table 6-5. Example permit requirement scenario for excavation of main Tijuana River source area and placement in City of Imperial Beach nearshore environment.

Agency Permit
Sediment Excavation Permit
Requirements - Main Proposed
Smugglers Gulch Sediment
Basin South of Monument Road
Sediment Placement Permit
Requirements – Nearshore
Beach Replenishment City of
Imperial Beach Notes
USACE Section 404/10 1
USFWS/NMFS/CDFW Incidental Take Permit
and/or Federal Section 7
Consultation
CCC/Local Cities Coastal Development
Permit
Dependent upon receiving site
location within an approved local
coastal plan and status, local
jurisdiction may issue a CDP.

CDFW 1600-1601 Streambed
Alteration Agreement
1 CDPR Encroachment Permit If nearshore replenishment
project encroaches onto CA
State Parks property,
encroachment permit required.

SLC Lease of State Lands
RWQCB 401 Certification/WDR
enrollment
1 City or County Grading Permit
Encroachment permit
Notes: USACE = U.S. Army Corps of Engineers; USFWS = U.S. Fish and Wildlife Service; NMFS = National Marine Fisheries Service; CDFW = California Department of Fish and Wildlife; CCC = California Coastal Commission; CDPR = California Department of Parks and Recreation; SLC = State Lands Commission; RWQCB = Regional Water Quality Control Board; WDR = Waste Discharge Requirement
1 Permit required if basin is built within jurisdictional area adjacent to stream.

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6.3 Permitting Process/Timeline
Implementing sediment excavation activities and beneficial reuse projects in the Valley will require multiple permits from a suite of federal and state agencies, depending on type of activity and project locations. Local agencies may also require additional grading and access permits, as well as potential variances to applicable ordinances for certain activities.

Individual project permits can require long lead times, extensive permit condition negotiations, and potentially onerous monitoring requirements.

Accordingly, a thorough, thoughtful permitting strategy can provide multiple benefits including saving time and short- and long-term costs.

Typically, the permitting process is divided into two components: local permits, such as grading, coastal development, and others issued by municipal agencies with local jurisdiction, and state and federal permits issued by respective regulatory agencies. It is important to begin with preparing local permit applications because many state and federal agencies require these as exhibits for issuing their own permits.

Additionally local permits often require less processing time allowing for review and approval in 6 months or less.

State and federal permits typically have more requirements than local permits and require longer lead time to process (Figure 6-1). In general. agencies have mandated application completeness response time parameters for permit applicants. However, the response time parameters are variable time among agencies. For example, the California Coastal Commission is required to respond within 30 days for a Coastal Development Permit application, but the Regional Water Quality Control Board has 60 days for a Section 401 Certification.

Typically, for complex or potentially environmentally sensitive projects such as sediment excavation and/or beneficial reuse in sensitive environments like the Valley, agencies request additional information to be provided to deem an application complete. There can be multiple rounds of information requests and project proponent submittals before an application is deemed complete. After each additional information submittal, agencies are granted an additional review window. This process is iterative and can be time-consuming. Depending on the permitting agency, scope of the project, level of environmental review, number of iterations required, and public comment and/or sensitivity to certain project details, issuance of certain types of federal and state permits can take one to several years.

Figure 6-1: Example Permit Timelines for Typical Sediment Management and Beneficial Reuse Projects

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INTENTIONALLY LEFT BLANK

SECTION 7
Monitoring and Reporting
14010
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7-1
7 Monitoring and Reporting
Monitoring of environmental effects will be required for beneficial reuse of sediment from the Valley. Disposal
of the sediment without a beneficial reuse component
will not necessitate monitoring. Monitoring is a
requirement of the permits to be secured for proposed
actions. Beneficial sediment reuse options requiring
monitoring include the following:
• Beach and nearshore nourishment
• Thin-layer sediment addition
• Levee rehabilitation
• Remedial cap
• Mine reclamation
The primary categories of monitoring that cover
biogeochemical conditions associated with material
removal, transport, and placement to be required are
as follows:
• Physical monitoring of landform (e.g.,
elevation, bathymetry, sedimentation, erosion)
• Biological monitoring of habitat and species
(e.g., riparian, salt marsh, and upland
including plants and animals, fish)
• Chemical monitoring of water and
sediment quality
Sections 7.1 and 7.2 provide additional detail on
each monitoring category and outline monitoring
requirements based on type of sediment reuse.

7.1 Typical Beneficial Reuse
Monitoring Requirements
Types of monitoring required for beneficial reuse
projects are briefly described below. For all projects, it is required prior to construction to set the baseline of the receiver site prior to disturbance, monitor during
construction to document any unintended adverse
impacts, and monitor then after construction to
document recovery or lack thereof. It serves as the
basis for regulatory agencies to quantify adverse
impacts from a project that trigger the need for
compensatory mitigation. A monitoring plan will be
required by the California Coastal Commission and
other agencies that demonstrates a satisfactory
monitoring approach to document changes,
potentially both positive and negative.

Physical Monitoring
Physical monitoring is typically done using
topographic and bathymetric (underwater) survey
methods. These can be traditional land-based
methods and/or done remotely with drones,
depending on the character of the site. Surveying
quantifies the three-dimensional elevation conditions
over the site and documents changes caused by the
project. Typically, a survey is conducted at both the
source location and the receiver site prior to
construction to verify the quantity placed and the
location of placement. In-water removal and/or
placement requires a similar approach to land-based
operations. Nearly all actions will trigger the need for physical monitoring.

Physical monitoring also includes the water quality
parameters of temperature, pH, salinity, dissolved
oxygen, biological oxygen demand, and turbidity.

These water quality constituents are typically
monitored in a water body or stream prior to and after
construction to document any impairment caused by
the project.

Biological Monitoring
Biological monitoring is conducted with a team that
documents many properties of the habitat such as
the presence of sensitive and endangered species;
vegetation type, cover, and maturity; and existence of
invasive vegetation. Specific surveys for endangered
bird species are conducted using specialized

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expertise according to established protocols by the
resource agencies. A wide variety of sensitive and
endangered birds may be present at this location due
to the multiple types of mature and functioning
habitat such as salt marsh, riparian, and upland. The
overall objective of the biological monitoring is to
determine if functioning habitat is disturbed by
material reuse operations including sediment
removal, transport, and placement.

The monitoring is done prior to construction, during
construction, and after construction to quantify changes caused by the project. Pre- and post-construction
monitoring is established as a systematic approach to
directly compare changes in habitat type, area,
function, and value. Therefore, consistent methods are
employed repeatedly over time to document
progressive change and habitat evolution. Monitoring
during construction is done to protect sensitive species and prevent inadvertent incursions into protected
areas. It is used to enforce restrictions, document
damage, and identify required mitigation if needed.

Chemical Monitoring
Chemical monitoring addresses potential
contamination in soils that can be contributed to a
receiver site. It involves sediment quality
characterization prior to sediment removal to prevent
contamination of a placement site. This work is
covered by the sampling and analysis plan process
overseen by the U.S. Army Corps of Engineers and
U.S. Environmental Protection Agency. Monitoring will
vary by project but will be required for every action
proposed herein. More specific information by project
type is provided in Section 7.2.

7.2 Monitoring Requirements
by Type of Beneficial Reuse
Probable monitoring requirements of potential
projects are detailed in Table 7-1 and followed by a
brief discussion of monitoring for each beneficial
reuse option. Monitoring of certain actions may be
required to extend well beyond the completion of
construction, such as for 5 years, while others may
not. Costs of monitoring can be fairly high and
range from $50,000 to $500,000 or more. For
reference, beach nourishment monitoring for the
Tijuana Estuary Fate and Transport Study project
was on the order of $500,000.

Beach Nourishment
This option triggers all of the monitoring requirements at the receiver site. Permits will require each type of monitoring with the exception of fish and
invertebrates. Beach nourishment typically requires
monitoring for up to 1 year after placement
depending on the quantity of material placed, with
longer periods required for larger projects done in
sensitive coastal areas.

Table 7-1. Probable Monitoring Requirements of Potential Projects Beneficial
Reuse
Monitoring Requirements
Sampling
and
Analysis
Plan
Process
Topography/
Bathymetry
Surveying
Water
Quality (at
least one of
turbidity,
DO, Temp,
pH, salinity)
Habitat
Mapping
(Marine,
Riparian,
Salt Marsh
or Upland)
Bird
Surveys
Fish and
Invertebrates
Burial by
Sediment
Beach
Nourishment
Yes Yes Yes Yes Yes No Yes
Thin Layer
Addition
Yes Yes Yes Yes Yes Yes Yes
Mine
Reclamation
Yes Yes No No No No No

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Thin Layer Addition
Thin layer addition also triggers monitoring of all types without exception. Placement of material over an
existing wetland is extremely sensitive and requires
careful scrutiny for up to 5 years after placement.

Mine Reclamation
Mine reclamation is less sensitive and may require
monitoring for the time needed to document
settlement of the fill and achievement of the target
final grades. Less monitoring is required of this option as it typically done in a less sensitive environment.

Table 7-2 shows the outline of probable monitoring
requirements for beach nourishment projects. This is
representative of any similar action proposed within
the Valley. Also, two specific example monitoring
plans are provided in Appendix E for actions related to beach nourishment with sediment from the Valley for
the same project. They are pertinent documents to
review and may serve as typical models of monitoring
plans that may be required for future actions.

Table 7-2. Overview of Anticipated Monitoring Requirements for Beach Nourishment Projects Overview of Anticipated Monitoring Requirements for Beach Nourishment Projects Project Phase Type of Monitoring Timing/Duration
Pre-Project/Baseline Survey (topographic and/or
bathymetric) of source location and
receiver site
Within one month of project start
Archeological Resources
• Identification of presence or
absence
Prior to project start
Biological Resources
• Habitat mapping
• Identification of sensitive
plants and wildlife
Within one month or less of project
start (based on permit specifics)
Sediment Characterization and
Testing (grain size, contaminants)
Prior to project start
Photo Documentation
• All areas of permanent and
temporary impact
Prior to project start
During Construction Construction best management
practice (BMP) monitoring
Daily or weekly during construction
(based on BMP)
Archeological Resources
• Protection of resources (if
applicable)
Daily or periodic (based on
resources)
Biological Resources
• Sensitive species
• Daily construction monitoring
• Periodic inspections
Daily and periodic during all
phases of construction
(coordination with regulatory
agencies required prior to
construction for specifics)
Sediment Characterization and
Testing (grain size, contaminants)
Potential for periodic testing
requirement
Water Quality at source location
and receiver site (at a minimum
temperature, pH, salinity, dissolved
oxygen, turbidity)
Daily or weekly during construction

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Table 7-2. Overview of Anticipated Monitoring Requirements for Beach Nourishment Projects Overview of Anticipated Monitoring Requirements for Beach Nourishment Projects Project Phase Type of Monitoring Timing/Duration
Visual observation of nourishment
site including:
• Speed and direction of
currents
• Tidal stage
• Trash/debris
• Oil/petroleum
• Discoloration and extent of any
visible turbidity plume
• Odors
Daily during nourishment activities
Photo Documentation
• All areas of permanent and
temporary impact
Periodic
Post-Construction Survey (topographic and/or
bathymetric) of source location and
receiver site to confirm quantity
placed
Upon completion of construction
Photo Documentation
• All areas of permanent and
temporary impact
Upon completion of construction
Post-Project Survey (topographic and/or
bathymetric)
Likely within 1 year of project
completion
Year(s) Following Project Survey (topographic and/or
bathymetric)
Possible requirement 1–5 years
after project completion

SECTION 8
Recommendations
14010
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8-1
8 Recommendations
Planning for effective sediment management in the
Valley requires consideration of multiple technical,
environmental, policy, and economic factors. Each
sediment source area includes unique stakeholders,
management components, reuse and disposal
process options, and multi-faceted regulatory
considerations. This Work Plan is intended to serve as
a reference and tool for development of short- and
long-term activities to support cost-effective sediment management activities. This section summarizes
recommendations and next steps that support the
vision of this Work Plan to advance more streamlined
management and permitting processes and provide
multiple social, environmental, and economic benefits
for the region.

8.1 Coordination
The complexity of bi-national watershed processes,
sediment transport and deposition dynamics, ongoing
sediment management, and beneficial reuse
operations within a framework of multi-jurisdictional
agency roles and responsibilities necessitates strong
coordination efforts among stakeholders.

Coordinating related projects, communities, and
programs can reduce duplication of services and
improve efficiency.

Stakeholders to be considered for coordinated efforts
in sediment management include the following:
• International
o CILA
o State of Baja
o CONAGUA
o City of Tijuana
• Federal
o International Boundary and
Water Commission U.S. Environmental
Protection Agency
o National Oceanic Atmospheric
Administration
o U.S. Army Corps of Engineers
o U.S. Fish and Wildlife Service
• State
o California Environmental Protection Agency
o California Department of Resources
Recycling and Recovery
o California Department of Parks and
Recreation
o State Water Resources Control Board
o California Department of Fish and Wildlife
o Regional Water Quality Control Board
o California Coastal Commission
o Ocean Protection Council
• Regional
o San Diego Association of Governments
o Integrated Regional Water Management
o San Diego County
o City of Imperial Beach
o City of San Diego
o City of Chula Vista
o Local Native American Tribes
o Local businesses with potential
sediment beneficial reuse opportunities
o Stakeholders concerned about
impacts to coastal resources, health,
safety, and surfing

KEY RECOMMENDATIONS FOR COORDINATION
▪ Forging partnerships and coordinating services
among stakeholders with similar goals is an
important strategy to successfully plan,
implement, and sustain efficient sediment
management activities.

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Coordination efforts may range from ad hoc informal
or formal meetings to development and
implementation of formal working agreements to
memoranda of understanding to implement projects
or programs. Early communication and coordination
among agencies and project stakeholders with
common administrative needs, sediment
management needs, and/or strategic goals may help
facilitate future project delivery.

8.2 Source Control
Sediment source control includes soil conservation
and stormwater management practices, as well as
point and non-point source contaminant controls,
designed to minimize anthropogenic contributions to
sediment loads naturally carried through dynamic
watershed systems, such as the Valley. Source
control efforts require careful planning and
participation of watershed stakeholders to implement
in a cost-effective manner and to maximize benefits.

Garnering participation in a watershed-scale
approach to sediment management can be a
challenge because there is often a disconnect in how
the sediment source impacts areas far downstream
via uncontrolled sediment discharges. In the Valley,
this disconnect is compounded by the bi-national
nature of the watershed, where many residents are
physically separated from downstream depositional
areas by the international border. Given this unique
condition, a focused bi-national approach to
promotion of sediment source controls is needed to
further social, environmental, and economic benefits
of various source control opportunities and
implementation options.

8.3 Reduce Barriers to
Beneficial Reuse
As described in previous sections, beneficial reuse of
sediment refers to the repurposing of local sediment
sources for activities that improve environmental
conditions, assist in infrastructure development,
and/or support local processes that can integrate
excess sediment into building and landscape
materials. However, in many locations, beneficial
reuse is constrained by a suite of regulatory,
technical, physical, and inter-organizational barriers

KEY RECOMMENDATIONS

FOR SOURCE CONTROL
▪ Educate the public in the United States and
Mexico on impacts of development and
impervious-surface-related erosion, as well
as source-control techniques.
▪ Provide technical support for urban
development, including grading and erosion
controls, site design, green infrastructure,
and operations and maintenance activities,
and include incentives for local
enforcement.
▪ Develop programs for incentives and local
enforcement of source control activities in
both the United States and Mexico.

KEY RECOMMENDATIONS TO MAXIMIZE

BENEFICIAL REUSE
▪ Create streamlined permitting approaches
for beneficial reuse projects meeting certain
predefined criteria.
▪ Support additional studies, modeling, and
pilot projects (see Section 8.6) to advance
beneficial reuse practices.
▪ Clarify expectations around the 80/20 rule
and use existing and potential future pilot
studies to support regulatory agency permit
condition development.
▪ Educate the public and regulatory agency
staff about sediment beneficial reuse
techniques, especially for beaches or
recreational areas.
▪ Relax the requirement for governments to
use the lowest-cost option when an
alternative meets diverse social or
environmental needs.
▪ Identify standardized methods to integrate
the environmental benefit of sediment
delivery to coastal environments into project
planning and analysis.
▪ Provide facilitation and incentives for interorganizational coordination and innovation. ▪ Support organizations to act as leaders in
regional sediment management via funding.
▪ Support existing inter-agency sediment
management workgroups to better
coordinate activities.

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(Ulibarri et al. 2020). Work is needed to support
development of sustainable beneficial reuse options
through development of cross-cutting solutions to
reduce barriers in implementation.

8.4 Permitting Strategies
Within the context of complex sediment excavation
and beneficial reuse projects with multiple agency
planning and permitting requirements, consideration
of permit efficiency strategies may provide multiple
stakeholder benefits. Permit efficiency strategies
range in scale and complexity from simple techniques,
like creation and use of baseline permit condition
templates, to development of multi-agency
partnerships and regional approaches for specific
sediment management activities. Key potential project
permitting efficiency strategies include the following:
• Submittal Ordering: Approved local agency
permits, including grading and, in some
cases, local stormwater ordinance
compliance documents, are often
requirements for and/or helpful exhibits for
certain regulatory agency permit
applications. Local agencies can have
relatively rapid processing times for certain
permit applications, especially with
coordination with local
agency representatives.
• Concurrent Application Submittals: State
and federal permit applications should be
prepared and submitted concurrently, to the
extent feasible, to retain consistency in
information content. Many of the permits
have overlapping but slightly different
planning and monitoring requirements.

Preparing documents that can be submitted
for multiple permits can promote efficiency,
consistency, and clarity. Also, submitting
permit applications to multiple agencies
concurrently is important because
permitting agencies coordinate; feedback
from one agency may be applicable to the
processing of other agency permits.
• Applicant-Drafted Permits: Regional
agencies and staff have conducted a suite
of sediment management projects ranging
from routine operations and maintenance
within limited existing disturbed locations to
complex in-situ excavation activities in
sensitive environmental areas. Additionally,
local and regional pilot projects and
innovative collaborations have allowed for
advancements in certain project
implementation strategies. In some cases,
previously issued regulatory agency permit
conditions for these projects provide
guidelines for future similar or related
sediment management project activities. As
part of development of this Work Plan,
typical 401 Water Quality Certification
permit conditions for beach nourishment
projects in San Diego were compiled and
reviewed with stakeholders (Appendix F).

Further documentation and evaluation of
existing permit conditions could be used to
proactively develop draft permit conditions
to initiate discussions with regulatory
agencies for future projects.
• Detailed Permit Condition Reviews:

Regulatory documents and agencygenerated permits often include “boilerplate” language that may be
inconsistent with the specifics of a given
project (e.g., a species identified in the
permit is not on the project site). An

KEY RECOMMENDATIONS

FOR PERMITTING EFFICIENCY
▪ Submittal ordering:
- Approved local agency permits.
- Followed by regulatory agency permits.
▪ Concurrent application submittals for state
and federal permits.
▪ Applicant-drafted permits that proactively
build off existing project permit conditions to
facilitate discussion with regulatory
agencies.
▪ Detailed permit condition reviews.
▪ Short-term permit condition alternative.
▪ Long-term mitigation condition specificity.

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8-4
experienced permitting specialist and the
project’s technical team (engineers,
construction managers, environmental
experts) should conduct a draft permit
review prior to advance negotiations with
the permitting agency to identify
unnecessary obstacles and develop
workaround solutions. Identification of key
elements and development of appropriate
solutions may assist in opening the way to
effective negotiations with the resource
agencies. Most permit language is
negotiable if the changes create greater
harmony between the permit language and
the project details.
• Short-Term Permit Condition Alternative:

Permits frequently have considerations that
are both short term (for construction) and
long term (for operation and mitigation). An
important short-term consideration is to
identify opportunities to negotiate
construction-term conditions to allow for
appropriate flexibility and reduce potential
project implementation delays. Boilerplate
language that may not apply to a particular
project, and may cause unnecessary delays,
can be identified and modified
where appropriate.
• Long-Term Mitigation Condition Specificity:

Vague or poorly worded long-term mitigation
requirements can become a significant
barrier to project success if impact
mitigation is included as part of the overall
project. In some cases, project proponents
are seeking sign-off on permit conditions up
to 5 years after the permit was written. This
timing can lead to regulatory staff not
involved in writing the original permit
language being asked to interpret vague or
complicated requirements and delay the
sign-off process. The more specific the
language, the less potential there is for
future disagreements about the
achievement of mitigation goals and
performance standards.

8.5 Data Management
Within the context of sediment management activities
in the Valley, a data management system to compile
and store information on key projects/programs will
allow for analysis that is critical for decision making and long-term cost efficiency. As agencies and
organizations create and consume data to support
project planning, permitting, implementation, and
reporting, effective data management solutions
become essential to development of sustainable,
efficient operations.

KEY RECOMMENDATIONS

FOR DATA MANAGEMENT
▪ Develop a centralized sediment
management project and data repository
with multiple agency contributors and
restricted/public access portals.
▪ Provide project planning and
permitting templates.
▪ Create an identification and tracking
mechanism for commercial applications and
markets of exported sediment material.
▪ Provide landfill disposal options
and capacity.

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8-5

8.6 Science Advancement
Science can play an essential role in shaping
planning, permitting, and implementation of diverse
sediment management activities in dynamic
environments like the Valley. Policies and projects
that support the development of improved data
collection and curation, comprehensive evaluation of
individual project and programmatic environmental
and logistical cost-benefits, and emerging pollutant
management technologies will support long-term
sustainable actions.

KEY RECOMMENDATIONS

FOR SCIENCE ADVANCEMENT
▪ Improved understanding of fate and
transport associated with beneficial reuse of
sediment within the nearshore ocean.
▪ Establishment of a regional program that
provides a process whereby opportunistic
material (with both optimum and less-thanoptimum sands) can be evaluated for compatibility and placed on a
predetermined beach nourishment site
under a programmatic approach for
sediment management.
▪ Integration of climate resiliency to long-term
sediment management planning.
▪ Implementation of microplastics testing and
removal research.

8.7 Funding
Current and projected sediment management needs
across the diverse matrix of federal, state, and local
agencies with responsibilities in the Valley suggest
various funding sources are needed to support
ongoing project planning and operations and
maintenance activities. Compounding factors of
ongoing sediment deposition in the Valley, historical
underfunding of sediment management capital
improvement projects and operations and
maintenance, increasingly stringent regulatory
requirements related to beneficial reuse options, and
low levels of federal and state financial support are
expected to continue to widen the gap between costs
and available funding for sediment management
activities. Left unaddressed, this chronic
underfunding can lead to flooding, water quality
impairments, property damage, higher future costs,
potential fines, and public liability costs. Inadequate funding for sediment management activities might
also have large-scale and long-term impacts on the
region’s environmental quality, infrastructure, and
public recreation resources. Accordingly, a
comprehensive and multi-faceted program to identify,
develop, and route sustainable funding sources
toward Valley sediment management needs is
necessary for long-term success.

KEY RECOMMENDATIONS

FOR FUNDING
▪ Identify funding options, financing
strategies, and opportunities to reduce
ongoing sediment management funding
needs through efficiencies and innovations.
▪ Evaluate potential funding strategy options
through a set of criteria, including whether
the options can provide cost recoverability
for Valley stakeholders.
▪ Benchmark sediment management
operations and maintenance and beneficial
reuse options against other regions to
support agency- and project-specific
planning and implementation efforts.
▪ Engage stakeholders, including policy and
budget decision-makers at the federal,
state, and local levels to accurately describe
needs, costs, and benefits.
▪ Prioritize projects and funding options to
support regional efficiency and costeffective solutions.

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SECTION 9
Next Steps and Conclusion
14010
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9-1
9 Next Steps and Conclusion
The recommendations presented in this Work Plan
are intended to support successful implementation of
sediment management projects throughout the Valley
over the next decade and beyond. A series of
interagency next steps were identified by the
Technical Advisory Committee (TAC) group members
in fall 2022; these steps have been organized into
short- and long-term goals in the sections below.

Short-term goals are achievable now through
interagency collaboration and the leveraging of
existing processes and programs to overcome known
hurdles to sediment management in the Valley. Longterm goals build on the short-term actions to support Valley-wide perspectives on sediment management
and streamlined pathways to project implementation.

9.1 Short Term Goals/
Current Action Items
The following broad short-term goals were identified,
discussed, and commented on by TAC group
members during final development of this Work Plan:
• Coordinated ongoing processes
• Project development/
implementation agreement
• Project-level pre-consultation meetings
• Legacy trash/sediment/debris cleanup
• Coordinated funding development
• University/research collaboration
Each goal is described further in the sections below.

Coordinated Ongoing Processes
There are numerous agencies and programs in the
United States and Mexico associated with ongoing
sediment management in the Valley. Coordination
efforts should leverage existing relationships and
explore new partnerships to increase efficiency for
existing and future operations. A short-term goal is to collaborate to identify shared goals and resources for
existing, ongoing projects.

Specific short-term action items for coordinated
ongoing processes include the following:
• Develop a list of existing, ongoing sediment
management processes, including contact
information, location, and other basic
program/project information that is updated
on an annual basis and available to the TAC
(potential starting point for future
centralized data repository).
• Identify and consolidate information for
existing or proposed projects with similar
timelines, goals, and other elements.
• Identify ongoing sediment management
operations with capacity to process and/or
store additional sediment from new or
existing sediment management operations.

Appropriate organizational coordination leads include
the International Boundary and Water Commission’s
Minute 320 Binational Core Group; the Tijuana River
Valley Recovery Team; working groups led by local,
regional, or state legislators; and working groups that may form in response to the proposed total maximum
daily loads for indicator bacteria and trash.

Project Development/Implementation Agreement
In addition to supporting implementation of existing
sediment management projects in the Valley,
development of new projects and
research/investigations were identified as short-term
goals by TAC group members. Continuation of existing
projects is not only important for maintaining
momentum of the overall sediment management
objectives identified for the Valley, but also to inform planning of new projects, including scheduling,
budget forecasting, and permitting. Research that
would support new projects includes pre-emptive

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9-2
studies to characterize new sediment sources and
feasibility of sediment sinks/receiver locations.

Specific short-term action items for project
development/implementation include the following:
• Develop a list of potential projects, including
contact information, location, and other basic
project information, as well as potential limiting
factors for implementation that is updated on
an annual basis and available to the TAC.
• Identify potential pilot projects.
• Create a list of potential receiver sites and
associated research needs and seek
regulatory consensus on their feasible use.
• Improve overall cost tracking for sediment
management projects by cataloguing existing
project cost by type and quantity.
• Improve individual project cost planning by
forecasting costs of operations and
maintenance in project planning/budgeting
(consider creating project
planning/budgeting templates).

Project-Level Pre-Application Consultation Meetings
Nearly all sediment management projects in the
Valley, including removal and beneficial reuse or
disposal, require approved environmental permits
from a suite of agencies prior to implementation.

Permit conditions development and approval
processes can often have lead times and require
detailed reviews. Accordingly, pre-permit application
consultation meetings with applicable regulatory
agencies during project planning can assist permit
applicants and agency staff in improving efficiency.

Section 6.2 of this Work Plan identifies the permitting and consultation requirements by sediment
management project type. The TAC group includes
representatives from these regulatory agencies with
previous sediment management projects in the Valley
and elsewhere in the United States. TAC group
feedback indicated that initiating consultation
meetings well in advance of permit application
submittal is an efficient way to define and refine
appropriate permit conditions applicable to site-,
project-, and agency-specific circumstances. Early
consultation can also be used to inform project
design, potentially minimize environmental impacts
and permit condition requirements, and facilitate
project implementation.

Specific short-term action items for pre-application
consultation meetings include the following:
• Early consideration of potential projectspecific requirements for consultation meeting requirements. Where feasible,
initiate discussions to facilitate development
of project description and/or exhibits needed
to support pre-application consultation
discussion of key issues.
• Develop timeline guidance by project type for
when to initiate consultation meetings and
appropriate frequency of consultation meetings
during the permit application processes.

Legacy Trash/Sediment/Debris Cleanup
Cleanup of legacy trash, sediment, and debris
impacting the Valley’s natural resources has both
short-term and long-term impacts. Effective cleanup
efforts require a combination of lead agency
organizational alignment with cleanup goals, support
volunteer/partner resources, access to key cleanup
site needs, funding for project development and
material disposal, and other administrative support
for tasks such as insurance, right-of-entry permits,
and waivers.

Specific short-term action items for trash, debris, and sediment cleanup efforts include the following:
• Identify appropriate agency representative
“champions” and support development of
management support for lead agency
organizational support.
• Facilitate relationships between appropriate
lead agency and volunteer/partner
resources to support repeatable cleanups.
• Define steps for a repeatable permitting
process to help streamline future
cleanup efforts.
• Compile and categorize cleanup site
information to support repeatable efforts.

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• Identify appropriate funding agencies and
resources for cleanup administrative and
disposal costs.

Coordinated Funding Development
A significant challenge to regional sediment
management is developing a multiagency approach
for securing project-level funding for capital
improvements and, more importantly, long-term
operations and maintenance activities. Due to the
fragmented distribution of land ownership and
maintenance responsibilities, historical sediment
management projects have typically been funded by
individual agencies or sources for project-specific
needs. This practice can sometimes limit the extent
and quantity of work and overall impact of the project.

A subset of the potential projects proposed in this
Work Plan will require multiagency coordination,
implementation agreements, and likely funding. Of
particular importance is the consideration of longterm agreements for performing and funding operations and maintenance for any Capital
Improvement Program project.

Specific short-term action items for developing a
coordinated funding approach are as follows:
• Evaluate existing projects and funding
sources to help identify gaps, potential
options, and pathways to fund future efforts.
• Coordinate with local, regional, and federal
legislators and elected officials to help
identify funding for sediment management
projects, including operations and
maintenance and support multiagency
collaboration at a legislative level.
• Develop a multiagency structure for
coordinating funding requests (e.g. Joint Powers
Authority, Memorandum of Understanding,
other) and administering projects.
• Identify funding pathways for
infrastructure/construction projects and longterm operations and maintenance. • Develop a coordinated approach for
funding regional operations and
maintenance programs.

University/Research Collaboration
Sediment-related research performed by universities
and public agencies has been critical for informing and supporting implementation of sediment management
projects in the Valley. Example topics of previous
research include sediment characterization, watershed
dynamic studies, riparian and estuary ecology studies,
nearshore and marine dynamic studies, project
opportunity prioritization, and policy analysis. A
continued and coordinated approach to baseline
research and special studies designed to improve
understanding of processes affecting Tijuana River
erosion, sediment transport, and impacts to ecology was identified by the TAC group to advance the regional
management goals identified in this Work Plan.

Specific action items for developing a coordinated
research approach are as follows:
• Develop support mechanisms, including
funding, agency partnerships, and ongoing
professional development to support ongoing
and planned research and special studies.

Look for overlaps in near-shore
replenishment research and monitoring being
conducted by the University of California at
Irvine and Southern California Coastal Water
Research Project.
• Coordinate with the funding and policy research
being conducted at San Diego State University.
• Correlate sediment management and
monitoring research projects in the region and
state to sediment management in the Valley.

9.2 Long Term Goals
Long-term sediment management goals and
strategies identified by the TAC group are flexible by
design to allow for adaptation following lessons
learned during implementation of the short-term
goals. The long-term strategies presented in this Work
Plan build on the short-term goals that emphasize a
multiagency, coordinated approach to sediment
management. As detailed above, short-term goals
focus on identifying and better supporting existing
processes, identifying project partnerships and pilot

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9-4
projects, clarifying and providing guidance on permit
requirements, identifying funding pathways, and
coordinating research efforts. Long-term strategies
seek to progress these efforts to the level of
formalized partnerships and streamlined project
implementation that is supported by research/pilot
projects and regional funding, and aligned with
resource agency goals. Identified long-term strategies
include the following:
• Coordinate interagency
project implementation.
• Build capacity for adaptive management.
• Develop a programmatic and/or streamlined
approach to environmental permitting.

Ideally, coordinated efforts to manage and responsibly
dispose of or re-use sediments, combined with
upstream source control, will create a sustainable
program for sediment management in the Valley.

Interagency Implementation Coordination
Long-term strategies for interagency coordination
focus on holistic approaches that incorporate agency
efforts in both the United States and Mexico. Source
control is a key concern for almost every agency that
manages sediment within the Valley. Approximately
two-thirds of the watershed is in Mexico, so
international collaboration is essential for source
control and the overall success of management
activities in the lower watershed.

Specific action items for interagency implementation
coordination are as follows:
• Develop a centralized sediment management
project and data repository with multiple
agency contributors.
• Work with Mexican officials to streamline
pathways for permitting and placement of
sediment from the Valley onto beaches in
Baja California.
• Look for collaborative solutions to sediment
management that include the use and
promotion of natural processes.
• Focus on partnerships that align with a
Valley-wide perspective to
sediment management.

Build Capacity for Adaptive Management
The long-term strategies presented in this section
are designed to follow an adaptive management
process. To do so, land managers and resource
agencies within the Valley must build a framework
for recording, analyzing, and evaluating results
from sediment management activities, and find a
central repository for which the data can be
accessed by stakeholders.

Specific action items to build capacity for adaptive
management include the following:
• Evaluate sediment management techniques
and technologies through implementation of
pilot studies.
• Maintain a database of permitting efforts by
project type and permitting approach to
assist new project planning.
• Document monitoring requirements by
project type and identify
successful strategies.
• Develop partnerships with university
research programs that have resources for
performing program assessments.

Programmatic/Streamlined Environmental Permits
The TAC group identified environmental permitting as
one of the more time-consuming and resourceintensive sediment management project planning activities. To help streamline the permitting process
for groups of similar projects, the TAC group seeks to
develop a programmatic approach to permitting that
will increase the viability of project success through
the reduction of repeated administrative work.

Environmental permitting is necessary to ensure that
projects consider the potential direct and indirect
impacts to the environment, but projects of similar
size, location, and technique may be able to share
overlapping components of the permitting process.

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9-5
Specific action items to develop a programmatic
approach to environmental permitting include
the following:
• Develop list of environmental permitting
needs and specific document requirements
by project type and location.
• Identify overlaps in monitoring requirements
that can be shared by multiple projects.

9.3 Conclusion
This Sediment Management Work Plan is intended to
serve as a guide for agencies and organizations
responsible for sediment management activities in
the Valley and in the upstream watershed of the
Tijuana River. It outlines watershed and coastal
processes that govern sediment deposition and
transport; potential sediment sources within the
watershed; a comprehensive list of sediment
management project components; and the regulatory
requirements for sediment management projects,
including permitting, monitoring, and reporting. The
future recommended activities should be cataloged
and assessed against the concepts and actions laid
out in this Work Plan to facilitate efficient, reasonable, and cost-effective actions to improve sediment
management and protect natural resources in the
Valley. The concepts, ideas, and recommendations
presented in this Work Plan were formulated based
on feedback received from the TAC group members,
and generally reflect the interests of participating
local, state, federal, and international stakeholders.

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SECTION 10
References
14010
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10-1
10 References
Biggs, T.W., K. Taniguchi, N. Gudiño-Elizondo, E. Langendoen, Y. Yuan, R. Bingner, D. Liden. 2018. Runoff and Sediment Yield on the US-Mexico Border, Los Laureles Canyon. Environmental Protection Agency Office of Research and Development National Exposure Research Laboratory. October 2018.

Brander, S.M., E. Hoh, K.M. Unice, K.R. Bibby, A.M. Cook, R.C. Holleman, D.V. Kone, C.M. Rochman, and J.A. Thayer. 2021. Microplastic Pollution in California: A Precautionary Framework and Scientific Guidance to Assess and Address Risk to the Marine Environment. California Ocean Science Trust, Sacramento, California.

CalRecycle (California Department of Resources Recovery and Recycling). 2010. Report of Trash, Waste Tire and Sediment Characterization. Tijuana River Valley, San Diego, California. Report prepared by URS Corporation.

CCSMW (California Coastal Sediment Management Workgroup). 2011. “California Coastal Sediment Master Plan – Brochure.” April 27, 2011.

CCSMW. 2017. Coastal Regional Sediment Management Plan, Eureka Littoral Cell, California. Prepared by CCSMW.

Drafts through December 2013 prepared by Moffatt & Nichol under contract to the U.S. Army Corps of Engineers, Los Angeles District. September 2017.

CDPR (California Department of Parks and Recreation). 2008. Final Initial Study Mitigated Negative Declaration for the Tijuana Estuary Sediment Fate and Transport Study. SCH Number: 2008011128.

CDPR. 2019. Notice of Preparation for the Nelson Sloan Quarry Restoration Project. April 2019. https://www.parks.ca.gov/pages/980/files/NOP_Nelson%20Sloan%20Restoration% 20Project_FINAL.pdf.

CDPR. 2021. Environmental Impact Report: Nelson Sloan Quarry Restoration and Beneficial Re-Use of Sediment Project. September 2021. Prepared by Dudek.

City of Imperial Beach. 2021. Tijuana River Valley Sediment Management Plan and Monitoring Program—Draft Monitoring Plan. Prepared by Wood. Submitted to the California Coastal Conservancy. July 2021.

City of Imperial Beach. 2022. Tijuana River Valley Sediment Management Plan and Monitoring Program – Technical Results Memorandum. April 2022. Prepared by Wood.

City of San Diego. 2007. Tijuana River Valley Local Coastal Program Land Use Plan. Updated March 2007. http://trnerr.org/wp-content/uploads/2013/04/TRV-Land-Use-Plan.pdf.

City of San Diego. 2008. City of San Diego General Plan. Updated March 10, 2008. https://www.sandiego.gov/ planning/programs/genplan#genplan.

City of San Diego. 2009. Smugglers Gulch Channel Excavation Spoils Sediment Characterization Report.

Prepared by URS.

Final Tijuana River Sediment Management Plan 10/ References 14010
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10-2
City of San Diego. 2011. Pilot Channel Borings and Sediment Characterization Report. Prepared by URS.

City of San Diego. 2012. Engineering Technical Memorandum, Geotechnical Analysis and Engineering Evaluation of the Tijuana River South Levee, U.S and Mexico Border, San Diego County, California. April 13, 2012.

City of San Diego. 2013. Tijuana River Sediment Loading – Smuggler’s Gulch and Tijuana River Pilot Channel. Draft Report prepared for City of San Diego Transportation and Storm Water Department, Storm Water Division.

Prepared by URS and HDR.

City of San Diego. 2015. DRAFT Tijuana River Valley Flood Management and Maintenance Obligations.

City of San Diego. 2022. “Miramar Landfill Acceptance Criteria for Disposal of Contaminated Soil.” https://www.sandiego.gov/sites/default/files/legacy/environmental-services/pdf/ep/soil0200att.pdf.

CIWMB (California Integrated Waste Management Board). Date Unknown. “Brown’s Fill Final Site Investigation Report – 2336 Hollister Street, San Diego, California.” CLSN (California Landscape Stewardship Network). 2020. Cutting Green Tape: Regulatory Efficiencies for a Resilient Environment. California Natural Resources Agency. November 2020. https://calandscapestewardshipnetwork.org.

County of San Diego. 2015. Sediment Monitoring Report. Prepared by Weston Solutions.

County of San Diego. 2020a. “SB 507 Needs & Opportunities Assessment: Potential Projects in the Main Tijuana River” [Handout]. Prepared by HDR. March 2020. Accessed June 17, 2022. https://www.sdparks.org/ content/dam/sdparks/en/pdf/Resource-Management/TJRVWaterQuality/Potential% 20Projects%20Summary%20Chart.pdf.

County of San Diego. 2020b. Tijuana River Valley: Needs and Opportunities Assessment. Prepared by HDR. March 2022. Accessed June 17, 2022. https://projectcleanwater.org/download/tijuana-river-valley-needs-andopportunity-assessment-noa-report/.

CSP (California State Parks). 2018. “Application for Permit – Goat Canyon Sedimentation and Basin Maintenance Dredging Project.” Submitted by California Department of Parks and Recreation. Submitted to U.S. Army Corps of Engineers. Application No. SPL-2005-02068-RRS.

Elgar, S., E.L. Gallagher, and R.T. Guza. 2001. “Nearshore Sandbar Migration.” Journal of Geophysical Research:

Oceans, 106(C6), pp.11623–11627.

EPA (U.S. Environmental Protection Agency). 2001. Methods for Collection, Storage, and Manipulation of Sediments for Chemical and Toxicological Analyses: Technical Manual.

EPA. 2022. “Resource Conservation and Recovery Act (RCRA) Overview.” Accessed January 27, 2022. https://www.epa.gov/rcra/resource-conservation-and-recovery-act-rcra-overview.

EPA and RWQCB (San Diego Regional Water Quality Control Board). 2010. Tijuana River Watershed Technical Support Document for Solids, Turbidity and Trash TMDLs. Report prepared by Tetra Tech.

Flick, R.E. 1993. “The Myth and Reality of Southern California Beaches.” Shore and Beach 61(3): 3–13.

Final Tijuana River Sediment Management Plan 10/ References 14010
March 2023
10-3
Garvey, K.J., and S. Brodeur. 2016. Huntington Harbour Dredging Project: Case Study of Dredge Material Re-Use with Multiple Benefits. ASCE COPRI/PIANC Ports Conference. New Orleans, Louisiana. June 12–15, 2016.

Goodrich, Kristen A., and Jonathan A. Warrick. 2015. “Fines: Rethinking our Relationship.” The Proceedings of the Coastal Sediments 2015. May 11–15, 2015.

Goodrich, K.A., Nicola Ulibarri, Richard Matthew, Paroma Wagle, Matthew Brand, Eric Stein , and Brett Sanders. 2019. “Co-Development of Coastal Sediment Management Approaches in Social Ecological Systems in Southern California.” Costal Sediments 2019. Pp. 1,821–1,825. https://www.worldscientific.com/ doi/10.1142/9789811204487_0157.

IBWC (International Boundary and Water Commission). 2018. 30% Report: Feasibility Study for Sediment Basins Tijuana River International Border to Dairy Mart Road. Report prepared by Stantec.

IBWC. 2020. Feasibility Study for Sediment Basins Tijuana River International Border to Dairy Mart Road Final Feasibility Report. Prepared by Stantec.

LACSTF (Los Angeles Contaminated Sediments Task Force). 2005. Long-Term Management Strategy. Prepared by Anchor Environmental CA, Everest International Consultants, and AMEC Earth and Environmental. May 2005.

Ludka, B.C., R.T. Guza, W.C. O’Reilly, M.A. Merrifield, R.E. Flick, A.S. Bak, T. Hesser, R. Bucciarelli, C. Olfe, B.

Woodward, and W. Boyd. 2019. “Sixteen Years of Bathymetry and Waves at San Diego Beaches.” Scientific Data, 6(1), pp.1–13.

NOAA (National Oceanic Atmospheric Administration). 2021. “Station 9410170.” Retrieved from NOAA Center for Operational Oceanographic Products and Services. https://tidesandcurrents.noaa.gov/ datums.html?id=9410170.

OPC (Ocean Protection Council). 2018. State of California Sea-Level Rise Guidance 2018 Update.

Patsch, K., and G.B. Griggs. 2006. Littoral Cells, Sand Budgets, and Beaches: Understanding California’s Shoreline.

Institute of Marine Sciences, University of California, Santa Cruz.

PopulationStat. 2021. “Tijuana, Mexico Population.” Tijuana, Mexico Population (2022) – Population Stat. Last modified August 1, 2021.

Republic Services. 2021. “Republic Services Special Waste Acceptance Guidelines.” January 2021.

RWQCB (Regional Water Quality Control Board). 2022. “San Diego Region –Tijuana River TMDLs for Indicator Bacteria and Trash.” https://www.waterboards.ca.gov/sandiego/water_issues/programs/tmdls/ tijuanarivervalley.html.

Safran, S.M., S.A. Baumgarten, E.E. Beller, J.A. Crooks, R.M. Grossinger, J. Lorda, T.R. Longcore, D. Bram, S.J. Dark, E.D. Stein, and T.L. McIntosh. 2017. Tijuana River Valley Historical Ecology Investigation. Prepared for the State Coastal Conservancy. A Report of SFEI-ASC’s Resilient Landscapes Program, Publication # 760, San Francisco Estuary Institute-Aquatic Science Center, Richmond, California.

SANDAG (San Diego Association of Governments). 2006. Final Sand Compatibility and Opportunistic Use Program Plan. Prepared by Moffatt & Nichol. March 2006.

Final Tijuana River Sediment Management Plan 10/ References 14010
March 2023
10-4
SANDAG. 2020. SANDAG 2019 Regional Beach Monitoring Program – Annual Report. Prepared for SANDAG by Coastal Frontiers Corporation under contract to BRG Consulting. May 2020.

SANDAG and CCSMW (California Coastal Sediment Management Workgroup). 2009. Final Coastal Regional Sediment Management Plan for the San Diego Region. Prepared by M&N in association with Everest International Consultants and Science Applications International Corporation. March 2009.

SWIA (Southwest Wetlands Interpretive Association). 2007. Goat Canyon Retention Basin Soil Particle Size Distribution Study. Report prepared by AMEC.

SWIA. 2017. Tijuana River Estuary Fate & Transport Study Summary Report for Coastal Managers. Prepared for Southwest Wetlands Interpretative Association by Everest International Consultants in association with Nordby Biological Consulting. March 2017.

TRVRT (Tijuana River Valley Recovery Team). 2013. Recovery Strategy: Living with the Water. https://www.waterboards.ca.gov/sandiego/water_issues/programs/tijuana_river_valley_strategy/.

Ulibarri, N., K.A. Goodrich, P. Wagle, M. Brand, R. Matthew, E. Stein, and B. Sanders. 2020. Barriers and Opportunities for Beneficial Reuse of Sediment to Support Coastal Resilience. Ocean and Coastal Management.

USACE (U.S. Army Corps of Engineers). 1991. Coast of California Storm and Tidal Waves Study, San Diego Region, State of the Coast Report. US Army Corps of Engineers, Los Angeles District.

USACE. 2018. Phase 1 Hydrology, Floodplain, and Sediment Transport Report Final. Tijuana River, United StatesMexico International Border to the Pacific Ocean, San Diego, California. US Army Corps of Engineers, Los Angeles District.

USACE. 2020. Phase 2 Hydrology, Floodplain, and Sediment Transport Report Final - Tijuana River, United StatesMexico International Border to the Pacific Ocean. A Planning Assistance to the States (PAS) Study prepared for City of San Diego. San Diego County, California.

USACE and EPA. 1998. Evaluation of Dredged Material Proposed for Discharge in Waters of the U.S. – Testing Manual. Inland Testing Manual. February 1998.

USACE and EPA. 2004. Evaluating Environmental Effects of Dredged Material Management Alternatives—A Technical Framework. EPA842-B-92-008. Revised May 2004.

USFWS (U.S. Fish and Wildlife Service). 2016. Habitat Conservation Planning and Incidental Take Permit Processing Handbook. https://www.fws.gov/library/collections/habitat-conservation-planning-handbook.

Warrick, J.A., K. Rosenberger, A. Lam, J. Ferreira, I.M. Miller, M. Rippy, J. Svejkovsky, and N. Mustain. 2012.

Observations of Coastal Sediment Dynamics of the Tijuana Estuary Fine Sediment Fate and Transport Demonstration Project, Imperial Beach, California. U.S. Geological Survey Open-File Report.

Zedler, J.B. 1983. “Freshwater Impacts in Normally Hypersaline Marshes.” Estuaries 6(4):346–355.

TIJUANA RIVER SEDIMENT MANAGEMENT WORK PLAN
Funding provided by State Coastal Conservancy through Proposition 68 California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018 resources Appendix A
Characteristics of Existing and Potential Sediment
Sources Table

14010
March 2023
1 Appendix A – Characteristics of Existing and Potential Sediment Sources Source Quantity Estimates1
Particle Size Distribution
Color
Contaminants Trash
2021/22 Monitoring Plastics
o Literature
2021/22
Monitoringo Literature
2021/22
Monitoringo Literature
Goat Canyon Sediment
Basin Complex
25,000–55,000 cy/yr based on
truck loads actual removal;
e
25,000–60,000 cy/yr based on
maintenance records;
b average
40,000 cy/yr but can hold 60,000
cy/yrc
Not monitored 60% sands, 40%
finesc
Both light and
dark material
(dark material
due to
organics
and/or
petroleum
hydrocarbons)a
Light gray to
pale olive,
micaceousd
No
hazardous
wasten
Possible
petroleum
hydrocarbonsa
Trash Evaluation
Rating: very high
Types observed:
cans, bottles,
paper, plasticso
Trash present;
c
large amounts
trash present
particularly at
debris screens and
in vegetationa
Estimated

40.9 pounds/
acre annually
b
Plastic detected
from visual
inspectiono
Smugglers Gulch (North
of Monument Road)
Smuggler’s and Pilot combined:
200–30,000 cy/yr (data from
1999–2013);
i
10,644 cy in 2001 and 668 cy in
2002g
10/21/21 1/7/22
Sand 15.7% 67.7%
Fines 84.8% 32.2%
Silty, clayey
(sometimes poorly
graded) sandb,f
Stockpile 1: 56%
sand, 8% fines,
14% cobbles, 22%
gravelb,f
Stockpile 2: 89%
sand, 8% fines, 3%
gravelb,f
Olive brownf
Light gray to
pale yellow
and olive gray
to olive,
micaceousd
No
hazardous
wasten
SVOCs/BEHP,
PAHs,
OCPs/4,4’-DDE
not detected
above
analytical
detection limit;
Dioxins and
Furans and
TPH carbon
chain data
available;
metals
exceedances:

CHHSLarsenic;
h
Metal
detections in
samples all
represent
background
DTSC levels,
with the
exception of
arsenic in the
stockpile,
hazardous
waste levels
found within
regulatory
limits;
f
Stockpile
sediment:

PAHs and OCPs
detected below
CHHSL/RSL;
4,4’ -DDT
detected above
Effects RangeLow and
Trash Evaluation
Rating: very high
Types observed:
plastic bags,
bottles, polystyrene,
paper, tires,
plastics, woodo
Estimated
13,454 lbs
present 2010h
Di(2-ehtyl
exyl)phthalate/DEHP
present in
concentrations well
below screening
criteriaf
Plastic bags and
other plastics from
visual inspectiono

14010
March 2023
2 Appendix A – Characteristics of Existing and Potential Sediment Sources Source Quantity Estimates1
Particle Size Distribution
Color
Contaminants Trash
2021/22 Monitoring Plastics
o Literature
2021/22
Monitoringo Literature
2021/22
Monitoringo Literature
requires further
investigation
for use in
marine
environment;
non-hazardous
when
compared to
hazardous
waste criteriac
Smugglers Gulch (South
of Monument Road)2
County excavation 8,000–10,000
cyp
10/21/21 1/7/22
Sand 15.7% 67.7%
Fines 84.8% 32.2%
Silty, clayey
(sometimes poorly
graded) sandb,f
Olive brownf
Light gray to
pale yellow
and olive gray
to olive,
micaceousd
No
hazardous
wasten
N/D Trash Evaluation
Rating: very high
Types observed:
plastic bags,
bottles, polystyrene,
paper, tires,
plastics, woodo
N/D Plastic bags and
other plastics from
visual inspectiono
Pilot Channel Smuggler’s North of Monument
Road and Pilot Channel combined:
200–30,000 cy/yr (data from
1999–2013)i
10/21/21 1/7/22
Sand 71.3% 79.0%
Fines 28.8% 21.4%

56.2% sand,

38.5% fines, 5.3%
graveld
Sand, silt, and
some gravelg
Slightly micaceous,
silty, clayey, sandd
Yellowishbrown, yellow,
and oliveg
Olive,
micaceousd
No
hazardous
wasten
SVOCs/BEHP,
PAHs,
OCPs/4,4’-DDE
not detected
above
analytical
detection limit;
Dioxins and
Furans and
TPH carbon
chain data
available;
metals
exceedances:

CHHSL-arsenich
Trash Evaluation
Rating: very high
Types observed:
plastic bags,
bottles, polystyrene,
paper, tires,
plastics, woodo
Trash screening
necessary
c
Plastic bags and
other plastics from
visual inspectiono

14010
March 2023
3 Appendix A – Characteristics of Existing and Potential Sediment Sources Source Quantity Estimates1
Particle Size Distribution
Color
Contaminants Trash
2021/22 Monitoring Plastics
o Literature
2021/22
Monitoringo Literature
2021/22
Monitoringo Literature
Tijuana River Main
Channel
109,000 cy sediment existing k, r –
approximately 1.7M cy sediment
and trash existing h; estimated
3,406 cy/yrk; International
Boundary and Water Commission
staff estimated up to 15,000
cy/yr
p
10/21/21 1/7/22
Sand 38.5% 70.6%
Fines 61.3% 29.5%
3%–27% fines,
6%–97% silt and
clay fractions,
remainder is sandj
Olive gray to
light olive gray,
micaceous
No
hazardous
wasten
SVOCs/BEHP,
PAHs,
OCPs/4,4’-DDE
not detected
above
analytical
detection limit
(one sample
with
SVOCs/BEHP

0.63- no units
or exceedance
level provided
in report),
Dioxins and
Furans and
TPH carbon
chain data
available;
metals
exceedances:

CHHSLarsenic;
h
Legacy
contamination
likelyk
Trash Evaluation
Rating: low
Types observed:
cigarette buttso
Estimated
1,087,943 lbs
present 2010;
h
trash/debris
present
k
N/D
Brown Fill Area3 16,000-35,000 cy one-time
removalq
10/21/21 1/7/22
Sand 17.2% 69.2%
Fines 82.9% 30.4%
N/D N/D No
hazardous
wasten
Low levels of
hydrocarbons
and herbicides;
metals
concentrations
lower than
DTSC
regulatory
limits,
presence of
diesel and
waste oil, solid
waste not
observed
Trash Evaluation
Rating: low4
Types observed:
plastico
3200 cy Municipal
Solid Waste,
asbestos
containing pipe
debris found in fill
Plastic detected
from visual
inspectiono

14010
March 2023
4 Appendix A – Characteristics of Existing and Potential Sediment Sources Source Quantity Estimates1
Particle Size Distribution
Color
Contaminants Trash
2021/22 Monitoring Plastics
o Literature
2021/22
Monitoringo Literature
2021/22
Monitoringo Literature
Tijuana Estuary N/D Not monitored Mouthl
Sand: 38.23%
Fines: 61.76%
Channelized Area
Upstream
Sand: 59.75%
Fines: 40.25%
Light gray,
olive gray, pale
olived
No
hazardous
wasten
— — Tijuana River and
the Tijuana River
Estuary are
impaired for trashm
Plastics presentm
Notes:
1 Existing quantity estimate information derived from numerous studies and resources, additional study may be required to refine site-specific estimates. 2 Smuggler’s Gulch south of Monument Road was assumed to have similar sediment characteristics to Smuggler’s Gulch north of Monument Road. Wood sampling occurred in both areas and was summarized as one location. 3 Brown Fill Area was evaluated as a potential sediment source however the amount of sediment available may be a limiting factor for re-use opportunities. 4 Brown Fill Area is known to contain high amounts of trash. The trash evaluation only included a visual examination of the surface soil.

References:
a SWIA 2007.
b City of San Diego 2013.
c CDPR 2008.
d USACE 2020.
e Biggs et al. 2018.
f City of San Diego 2009.
g City of San Diego 2011.
h CalRecycle 2010.
i City of San Diego 2015.
j
IBWC 2018.
k IBWC 2020.
l County of San Diego 2015.
m EPA and RWQCB 2010.
n No hazardous waste by the standards of Title 22 Section 66261.24 TTLC comparison; zero exceedances of the TTLC, STLC or TCLP benchmarks. (City of Imperial Beach 2022). o City of Imperial Beach 2022.

P CDPR 2021.
q CIWMB no date.
r City of San Diego 2012.

TIJUANA RIVER SEDIMENT MANAGEMENT WORK PLAN
Funding provided by State Coastal Conservancy through Proposition 68 California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018 resources Appendix B
Draft Tijuana River Valley Sediment Management Plan
and Monitoring Program Technical
Results Memorandum

TIJUANA RIVER VALLEY SEDIMENT MANAGEMENT PLAN AND MONITORING

PROGRAM

TECHNICAL RESULTS MEMORANDUM

PRELIMINARY FINAL
Submitted to:

California Coastal Conservancy
on behalf of the City of Imperial Beach
Prepared by:

July 2022

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
Page i

EXECUTIVE SUMMARY
To support development of a Tijuana River Valley Sediment Management Plan (Management Plan) and evaluate potential sediment reuse opportunities in the Tijuana River Valley, the Water Quality and Sediment Monitoring Program (Monitoring Program) was developed and then implemented. Water Quality Characterization Monitoring was conducted to supplement the existing dataset characterizing indicator bacteria levels at main river and canyon inputs to the Tijuana River and better characterize the conditions of what enters the Tijuana River Valley from cross border flows (related to sediment and water quality). Sediment Characterization Monitoring and Trash Evaluations were conducted to provide baseline data to guide potential management options for reuse or disposal of sediment from areas within the Tijuana River Valley.

Study locations included the main channel, canyon inputs, and valley of the Tijuana River. The Monitoring Program was conducted from March 2021 through January 2022, and comprised two wet weather water quality characterization events, two dry weather water quality characterization events and two dry weather sediment and trash characterization events.

Water Quality Characterization Monitoring: Water quality measurements including in-situ field constituents, chemical parameters and indicator bacteria were taken during both dry and wet weather conditions and compared to Basin Plan water quality objectives (WQOs), non-stormwater action level (NAL) and stormwater action level (SAL) regulatory benchmarks from the MS4 Permit (San Diego Water Board, 2015), and Border Patrol Study results (United States Customs and Border Protection, 2018). Basin Plan WQOs establish thresholds/water quality standards applicable to discharges to inland surface waters, enclosed bays and estuaries considered protective of a range of uses (beneficial uses applicable to Tijuana River Valley include recreation [REC-1, REC-2], warm freshwater habitat [WARM] and wildlife habitat [WILD]). Most Water Quality Characterization results exceeded applicable WQOs from the Basin Plan, NALs and SALs, and resulted in worse condition than results from the Border Patrol Study from 2018.

Sediment Characterization Monitoring: Sediment was sampled from five sediment source areas to identify potential reuse opportunities from each source area. Monitoring was conducted during dry weather and samples were analyzed according to the Cal/EPA Total Threshold Limit Concentration (TTLC), Soluble Threshold Limit Concentration (STLC), and federal Toxicity Characteristic Leaching Procedure (TCLP) thresholds. Results were compared to California Code of Regulations Title 22 Section 66261.24 (Title 22) hazardous waste determination thresholds to determine if the sediment contained any hazardous waste properties that make it potentially dangerous or harmful to human health or the environment. Existing sediment characterization data for two additional potential reuse source areas, Goat Canyon Sediment Basin Complex and the Tijuana Estuary, were evaluated in lieu of monitoring.

Trash Evaluations: Visual assessments of trash conditions were conducted at the same sediment source areas to support determination of sediment reuse potential, with the highest densities of trash found at Goat Canyon and the main Tijuana River flood control channel and the lowest at the Brown Fill Project.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
Page ii
Sediment reuse and disposal opportunities being considered are:
• Beach and nearshore nourishment
• Thin-layer sediment addition
• Mine reclamation
• Construction material
• Levee rehabilitation
• Commercial landfill
• Remedial cap
• Landfill daily cover
• Upland landfill disposal
The average results from both sediment sampling and the existing data evaluation yielded no exceedances of Title 22 TTLC, STLC, or TLCP benchmarks, meaning none of the samples were initially considered hazardous for the analytes monitored. Overall, sediment monitoring results indicated that tested sediment source areas were not hazardous and therefore have potential for reuse or disposal, provided completion of further required sediment monitoring and testing for each specific use (Figure ES-1).

Figure ES-1
Potential Options for Sediment Reuse and Disposal in Tijuana River Valley

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
Page iii

TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY .............................................................................................................i Acronyms and Abbreviations ..................................................................................................v

1.0 Introduction ................................................................................................................1-1

2.0 Water Quality Characterization Monitoring ..............................................................2-1

2.1 Water Quality Characterization Monitoring Methods .......................................................2-1

2.2 Water Quality Characterization Monitoring Results .........................................................2-2

2.2.1 Dry Weather Water Quality Results ....................................................................2-2

2.2.2 Wet Weather Water Quality Results ...................................................................2-4

2.2.3 Water Quality Characterization Monitoring QA/QC Results Summary...............2-6

2.3 Water Quality Characterization Data Assessment...........................................................2-6

2.3.1 San Diego Basin Plan Data Comparisons ..........................................................2-6

2.3.2 MS4 Permit NAL and SAL Data Comparisons ...................................................2-8

2.3.3 Border Patrol Study Data Comparisons..............................................................2-9

3.0 Sediment Characterization Monitoring .....................................................................3-1

3.1 Sediment Characterization Monitoring Methods..............................................................3-1

3.2 Sediment Monitoring Results ...........................................................................................3-1

3.2.1 Sediment Characterization Monitoring QA/QC Results Summary .....................3-3

3.3 Sediment Characterization Monitoring Data Assessment ...............................................3-3

3.4 Existing Sediment Data Assessment...............................................................................3-8

3.4.1 Estuary Sediment Characterization ....................................................................3-9

3.4.2 Goat Canyon Sediment Characterization .........................................................3-12

4.0 Trash Evaluations.......................................................................................................4-1

4.1 Trash Evaluation Methods ...............................................................................................4-1

4.2 Trash Evaluation Results .................................................................................................4-3

4.3 Trash Evaluation Data Assessment.................................................................................4-5

5.0 Monitoring Program Conclusion Summary..............................................................5-1

6.0 References..................................................................................................................6-1

LIST OF TABLES
Table 2-1 Antecedent Dry Days for Dry Weather Water Quality Characterization Monitoring Events ....................................................................................................2-2 Table 2-2 Dry Weather Water Quality Characterization Results ...............................................2-3 Table 2-3 Rainfall Totals for Wet Weather Water Quality Characterization Monitoring Events......................................................................................................................2-4 Table 2-4 Wet Weather Water Quality Characterization Results ..............................................2-5 Table 2-5 Water Quality Characterization Results Comparison to Basin Plan WQOs...............2-7 Table 2-6 Water Quality Characterization Results Comparison to MS4 Permit NALs and SALs ........................................................................................................................2-9 Table 2-7 Water Quality Characterization Dry Weather Results Data Comparison to Border Patrol Study Results ...................................................................................2-11

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
Page iv
Table 2-8 Water Quality Characterization Wet Weather Results Data Comparison to Border Patrol Study Results ...................................................................................2-13 Table 3-1 Sediment Characterization Monitoring Comparison to Title 22 Benchmarks.............3-6 Table 3-2 Sediment Characterization Monitoring Hazardous Material Assessment by Location ...................................................................................................................3-8 Table 3-3 TETRP Report Results and Comparison to Title 22 Benchmarks.............................3-9 Table 3-4 Goat Canyon Report Results and Comparison to Title 22 Benchmarks..................3-13 Table 4-1 Trash Evaluation Results .........................................................................................4-4

LIST OF FIGURES
Figure ES-1 Potential Options for Sediment Reuse in Tijuana River Valley ................................ ii Figure 2-1 Overview Map of Water Quality Characterization Monitoring Locations and Waterbodies ...........................................................................................................2-1 Figure 3-1 Evaluated Sediment Source Areas .........................................................................3-2 Figure 3-2 Sediment Characterization Sampling Timeline........................................................3-4 Figure 3-3 Flowchart for Hazardous Waste Determination under Title 22.................................3-5 Figure 4-1 Trash Category Example Photos ............................................................................4-2 Figure 4-2 Trash Evaluation Results ........................................................................................4-5 Figure 4-3 Trash Evaluation Results Map ................................................................................4-6 Figure 5-1 Potential Reuse Opportunity Results.......................................................................5-3

LIST OF ATTACHMENTS
Attachment A QA/QC Results for Water Quality and Sediment Characterization Monitoring Attachment B Field Data Sheets for Water Quality Characterization Monitoring Attachment C Laboratory Reports for Water Quality Characterization Monitoring Attachment D Water Quality Characterization Monitoring Result Graphs Attachment E Complete Results for Sediment Characterization Monitoring Attachment F FDS for Sediment Characterization Monitoring Attachment G Laboratory Reports for Sediment Characterization Monitoring Attachment H FDS for Trash Evaluations

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
Page v
Acronyms and Abbreviations
° Degree
% Percent
Basin Plan San Diego Basin Plan (San Diego Water Board, 2008) CBOD Carbonaceous Biochemical Oxygen Demand
CCR California Code of Regulations
DI Deionized
DO Dissolved Oxygen
E. coli Escherichia coli
ELAP Environmental Laboratory Accreditation Program
EPA Environmental Protection Agency
FDS Field Data Sheet
FIB Fecal Indicator Bacteria
g Grams
HEM Oil & Grease Hexane-Extractable Material
ID Identification
Inland Testing Manual Dredged Material Proposed for Discharge in Waters of the US - Testing Manual
kg Kilograms
LCS Laboratory Control Samples
LD Laboratory Duplicate
Management Plan Tijuana River Valley Sediment Management Plan and Monitoring Program mg Milligrams
mL Milliliter(s)
Monitoring Program Water Quality and Sediment Monitoring Program in Support of the Management Plan
MPN Most Probable Number
MQO Measurement Quality Objectives
MS4 Municipal Separate Storm Sewer System

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ACRONYMS AND ABBREVIATIONS (continued)
Page vi
MS4 Permit
Order Number R9-2013-0001, as amended by Order Nos. R9-2015-0001 and R9-2015-0100: National Pollutant Discharge Elimination System Permit and Waste Discharge Requirements for Discharges from the Municipal Separate Storm Sewer System (MS4) Draining the Watersheds Within the San Diego Region (San Diego Water Board, 2015) MS Matrix Spike
MSD Matrix Spike Duplicate
mS Millisiemens
mV Millivolts
NA Not Applicable
NAL Non-Storm Water Action Level
ng Nanograms
ORP Oxygen Reduction Potential
PAH Polycyclic Aromatic Hydrocarbons
PCB Polychlorinated Biphenyls
pCi Picocurie Radioactive Unit
*.pdf Portable Document Format
pH Scale for Potential of Hydrogen
Project Monitoring Program Project
QA Quality Assurance
QC Quality Control
RL Reporting Limit
RPD Relative Percent Difference
SAL Storm Water Action Level
San Diego Water Board San Diego Water Quality Control Board SCOUP Sand Compatibility and Opportunistic Use Program Plan SRM Standard Reference Material
SSM Single Sample Maximum
STLC Soluble Threshold Limit Concentration

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ACRONYMS AND ABBREVIATIONS (continued)
Page vii
STV Statistical Threshold Value
SVOCs Semi-Volatile Organic Compounds
TCLP Toxicity Characteristic Leaching Procedure
TPH Total Petroleum Hydrocarbon
TRPH Total Recoverable Petroleum Hydrocarbons
TSS Total Suspended Solids
TTLC Total Threshold Limit Concentration
ug/kg Micrograms per Kilogram
USACE United States Army Corps of Engineers
USEPA United States Environmental Protection Agency
VOCs Volatile Organic Compounds

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

1.0 Introduction
The Water Quality and Sediment Monitoring Program (Monitoring Program) was developed in support of the Tijuana River Valley Sediment Management Work Plan (Management Plan). This Monitoring Program was developed to characterize water quality and sediment reuse potential in the Tijuana River Valley under the Coastal Conservancy Grant, which was awarded to develop the overall Management Plan and address unique sediment management challenges in the Tijuana River Valley. The three elements of the Monitoring Program included:
• Water Quality Characterization Monitoring for fecal indicator bacteria (FIB), total suspended sediment (TSS), and carbonaceous biochemical oxygen demand (CBOD) in cross-border flows;
• Sediment Characterization Monitoring for characterization of sediment quality and reuse potential; and
• Trash Evaluations to determine the quantity and types of trash present to assess the impact of accumulated trash on potential sediment disposal and reuse opportunities.

The Monitoring Program was conducted from March 2021 through January 2022, and comprised two wet weather water quality characterization events, two dry weather water quality characterization events and two dry weather sediment and trash characterization events. Details regarding monitoring methods can be found in the “Tijuana River Valley Sediment Management Plan and Monitoring Program: Monitoring Plan” (Wood Environment & Infrastructure Solutions, Inc., 2021). This Technical Memorandum describes the results of monitoring efforts and assessments performed under the Monitoring Program and provides preliminary conclusions based on the results of the assessment.

Water Quality Characterization monitoring was intended to add to the current available data set and characterize indicator bacteria levels at main river and canyon inputs to the Tijuana River and in the Tijuana River Valley. Results from Water Quality Characterization monitoring were compared against applicable water quality objectives (WQOs) from the San Diego Basin Plan (San Diego Water Board, 2008), NAL and SAL regulatory benchmarks from the MS4 Permit (San Diego Water Board, 2015) and results from a previously completed water quality study (United States Customs and Border Protection, 2018). Sediment Characterization Monitoring and Trash Evaluations were intended to provide baseline data to guide potential management options for reuse or disposal of sediment from areas within the Tijuana River Valley. Where recent sediment data was available, assessment of existing data was performed in lieu of monitoring. This included two sites: Tijuana River Estuary and Goat Canyon Sediment Basin Complex. Results from both the sediment and trash evaluations were used to inform potential sediment reuse or disposal options for the seven sediment source areas assessed in this study.

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2.0 Water Quality
Characterization
Monitoring
Seven monitoring locations were selected to characterize indicator bacteria levels at the main river and canyon inputs to the Tijuana River and in the Tijuana River Valley (Figure 2-1). Water quality monitoring locations were sampled twice each in dry weather and wet weather.

Figure 2-1
Overview Map of Water Quality Characterization Monitoring Locations and Waterbodies

2.1 Water Quality Characterization Monitoring Methods
The collection of Water Quality Characterization samples at each of the seven sites adhered to sampling protocols outlined in "Standard Operating Procedures (SOP) for the Collection of Bacteria Samples from Storm Drains and Receiving Waters (Creeks, Lagoons, Bays, and Ocean)" used by the San Diego Copermittees for the Coastal Storm Drain and Lagoon Monitoring (County of San Diego, 2007). This included collection of grab samples from the middle of the water column height or just below the water surface to avoid collecting surface scum and sediment from the bottom, where possible. After sample containers were filled, they were promptly placed on ice in

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a clean cooler (maximum temperature of 10 degrees Celsius) in the dark and transported to the laboratory for processing to meeting holding times. Additionally, in-situ field measurements were performed for pH, conductivity, temperature, dissolved oxygen (DO), oxidation reduction potential (ORP), and turbidity using a multi-parameter water quality meter. Field measurements for each site were recorded on field data sheets (FDSs), along with field observations and potential sources of pollutants within the vicinity of each site. For full details on Water Quality Characterization Monitoring methods, see section 3.2 of the Monitoring Plan (Wood, 2021).

2.2 Water Quality Characterization Monitoring Results
This section presents the results of dry and wet weather water quality characterization monitoring, completed between March and December 2021.

2.2.1 Dry Weather Water Quality Results
During both dry weather sampling events, grab samples and in-situ field measurements were successfully collected at seven locations. Enviromatrix Analytical, Inc., an ELAP certified laboratory, provided analytical services for chemistry and indicator bacteria parameters. Table 2-1 details the antecedent dry periods and dates for each dry weather sampling event, while Table 2-2 presents results for both dry weather events. Quality Assurance/Quality Control (QA/QC) results are presented in Attachment A. Field data sheets for these sampling events are in Attachment B, and laboratory reports with results are in Attachment C.

Table 2-1
Antecedent Dry Days for Dry Weather Water Quality Characterization Monitoring Events Event Dry Weather Event 1 Dry Weather Event 2
Event Date 6/23/21 11/12/21
Antecedent Dry Days1 119 days 9 days
Notes:

1. As measured by rainfall at San Ysidro ALERT Gauge (https://sandiego.onerain.com/home.php). Antecedent dry days defined as number of days before sampling event that received <0.1 inches of rainfall.

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Table 2-2
Dry Weather Water Quality Characterization Results
Site ID Yogurt Canyon
(YGTCYN)
Goat Canyon
(GOATCYN)
Smuggler's Gulch
(SMGGLCH)
Silva's Drain
(SILVDR)
Canyon Del Sol
(CYNSOL)
Stewart's Drain
(STEWDR)
Tijuana River Main Channel
(TJMAIN)
Event Date 6/23/21 11/12/21 6/23/21 11/12/21 6/23/21 11/12/21 6/23/21 11/12/21 6/23/21 11/12/21 6/23/21 11/12/21 6/23/21 11/12/21 Dissolved Oxygen
(DO) (mg/L) 6.1 5.62 6.98 7.68 7.65 1.65 6.48 8.03 7.88 NC (Dry) 8.00 2.02 2.85 5.74 pH 7.54 7.5 8.0 8.09 7.68 7.92 8.34 8.05 7.54 NC (Dry) 8.44 6.68 8.37 8.05 Specific Conductivity
(mS/cm) 1.378 6.259 1.31 2.827 0.377 2.223 2.007 2.96 0.953 NC (Dry) 2.016 2.542 5.66 3.599 Temperature
(°C) 21.3 15.8 23.2 18.1 21.7 17.1 20.8 16.9 21.8 NC (Dry) 20.4 15.2 19.6 23.4 Oxidation Reduction
Potential (ORP)
(mV) 1
130.8 NC 127.5 NC 112 NC -6.0 NC 14 NC (Dry) NC NC NC NC Turbidity
(NTU) 103 20.63 2,460 302.17 116.2 264.81 53.3 198.75 465 NC (Dry) 63.7 350.48 1,036 33.26 Carbonaceous
Biochemical Oxygen
Demand (CBOD)
(mg/L)

52.4 8.64 128 17.6 57.8 121 76.0 218 455 NC (Dry) 119 400 43.6 <20 Total Suspended
Solids (TSS)
(mg/L)
148 24 11,500 21,600 199 66 160 700 2,700 NC (Dry) 272 6,380 22 72 Total Coliform
(MPN/100mL) 1,410,000 8,160 >2,420,000 >2,420,000 >2,420,000 >2,420,000 >2,420,000 >2,420,000 >2,420,000 NC (Dry) 866,000 >2,420,000 >2,420,000 276,000 Fecal Coliform
(MPN/100mL) 240,000 400 >1,600,000 >1,600,000 <2,000 >1,600,000 900,000 >1,600,000 >1,600,000 NC (Dry) 240,000 >1,600,000 800 2,000 E. coli (MPN/100mL) 435,000 200 >2,420,000 >2,420,000 9,600 >2,420,000 548,000 >2,420,000 >2,420,000 NC (Dry) 45,700 >2,420,000 <1,000 2,000 Enterococcus
(MPN/100mL) 155,000 100 >2,420,000 980,000 75,600 1,300,000 866,000 >2,420,000 >2,420,000 NC (Dry) 225,000 1,050,000 2,380 9,700 Notes:
> = exceeded upper limit of reportable range; < = less than; >= greater than; °C = degrees Celsius; CBOD = Carbonaceous Biochemical Oxygen Demand; cm = centimeter; DO = dissolved oxygen; E. coli = Escherichia coli; ID = identification; L = liter; mg = milligrams; MPN/100mL = Most Probable Number per 100 milliliters; mS = millisiemens; mV = millivolts; NC = not collected; NTU = Nephelometric Turbidity Unit; ORP = oxidation reduction potential; pH = Scale for potential of hydrogen; TSS = total suspended solids

1. Field meter used during the November 12, 2021 event did not have ORP measurement capability.

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2.2.2 Wet Weather Water Quality Results
During both wet weather sampling events, grab samples and in-situ field measurements were successfully collected at seven locations. Enviromatrix Analytical, Inc., provided analytical services for chemistry and indicator bacteria parameters. Rainfall totals for each event are presented in Table 2-3, while Table 2-4 presents the results from both wet weather events. QA/QC results are presented in Attachment A. Field data sheets for these sampling events are in Attachment B, and laboratory reports with results are in Attachment C.

Table 2-3
Rainfall Totals for Wet Weather Water Quality Characterization Monitoring Events Event Wet Weather Event 1 Wet Weather Event 2
Event Date 3/10/21 12/14/21
Rainfall Total (inches)1 0.84 1.16
Notes:

1. Rainfall total at San Ysidro ALERT Gauge (https://sandiego.onerain.com/home.php)

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Table 2-4
Wet Weather Water Quality Characterization Results
Site ID Yogurt Canyon
(YGTCYN)
Goat Canyon
(GOATCYN)
Smuggler's Gulch
(SMGGLCH)
Silva's Drain
(SILVDR)
Canyon Del Sol
(CYNSOL)
Stewart's Drain
(STEWDR)
Tijuana River Main Channel
(TJMAIN)
Event Date 3/10/21 12/14/21 3/10/21 12/14/21 3/10/21 12/14/21 3/10/21 12/14/21 3/10/21 12/14/21 3/10/21 12/14/21 3/10/21 12/14/21 Dissolved Oxygen (DO)
(mg/L) 5.04 6.75 5.48 7.88 6.00 6.17 8.45 6.38 6.42 6.35 1.58 4.37 2.95 7.02 pH 7.56 9.15 8.49 9.36 8.18 8.77 8.21 8.63 8.10 8.97 7.24 7.98 7.80 9.23 Specific Conductivity
(mS/cm) 0.8220 0.2414 0.8450 0.6860 0.6970 0.5860 0.4990 0.4016 1.220 0.5690 1.130 0.8330 0.8570 0.2382 Temperature
(°C) 17.64 15.40 20.78 14.50 19.80 15.90 16.77 16.70 18.11 16.10 18.26 16.70 18.39 15.80 Oxidation Reduction
Potential (ORP)
(mV)
-9.0 -60.9 -19.0 40.4 24.0 -56.9 7.0 3.5 -58.0 38.7 -136.0 76.0 82.0 59.6 Turbidity (NTU) 38.9 >1,000 >1,000 >1,000 322 >1,000 270 665 269 447 508 746 814 >1,000 Carbonaceous
Biochemical Oxygen
Demand (CBOD)
(mg/L)
<20 26.7 49.2 158 42.7 212 25.0 88.6 230 167 220 268 49.1 54.2 Total Suspended Solids
(TSS) (mg/L) 28 1,270 3,820 29,900 262 1,150 128 5,980 204 450 1,060 1,050 832 3,260 Total Coliform
(MPN/100mL) 1,410,000 >242,000 >2,420,000 >2,420,000 >2,420,000 <1001 1,550,000 >2,420,000 >2,420,000 >2,420,000 >2,420,000 >2,420,000 >2,420,000 >2,420,000 Fecal Coliform
(MPN/100mL) >1,600,000 500,000 >1,600,000 >1,600,000 1,600,000 >1,600,000 300,000 500,000 >1,600,000 >1,600,000 >1,600,000 >1,600,000 >1,600,000 >1,600,000 E. coli (MPN/100mL) 39,900 173,000 >2,420,000 1,990,000 >2,420,000 <1001 88,200 1,410,000 >2,420,000 >2,420,000 >2,420,000 >2,420,000 1,990,000 866,000 Enterococcus
(MPN/100mL) 34,500 242,000 1,550,000 >2,420,000 1,200,000 1,730,000 214,000 345,000 1,730,000 >2,420,000 1,990,000 >2,420,000 613,000 1,730,000 Notes:
< = less than; >= greater than; °C = degrees Celsius; CBOD = Carbonaceous Biochemical Oxygen Demand; cm = centimeter; DO = dissolved oxygen; E. coli = Escherichia coli; ID = identification; L = liter; mg = milligrams; MPN/100mL = Most Probable Number per 100 milliliters; mS = millisiemens; mV = millivolts; NTU = Nephelometric Turbidity Unit; ORP = oxidation reduction potential; pH = Scale for potential of hydrogen; TSS = total suspended solids

1. During the data QA process, result was flagged. A lab error was suspected in these results. Based on previous results, the magnitude of Total Coliform and E. Coli results are anticipated to match those of Fecal Coliform and Enterococcus. For the purposes of this study, these results were rejected and were not assessed against benchmarks.

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2.2.3 Water Quality Characterization Monitoring QA/QC Results Summary Water quality data were compared with applicable measurement data quality objectives (MQOs) defined in the Monitoring Plan (Wood, 2021). Both field QA/QC samples (field duplicates and field blanks) and laboratory QA/QC samples (method blanks, lab duplicates, and standard reference material) were assessed against MQOs. Only one field duplicate MQO (CBOD >25% RPD) and one field blank MQO (CBOD >RL) were exceeded during the course of this monitoring. See Attachment A for more information.

2.3 Water Quality Characterization Data Assessment
Dry and wet weather sample results for each site were compared to:
• Applicable San Diego Basin Plan WQOs (San Diego Regional Water Quality Control Board (San Diego Water Board, 2008) (Table 2-5);
• Applicable non-stormwater action level (NALs) and stormwater action levels (SALs) from the MS4 Permit (San Diego Water Board, 2015) (Table 2-6); and • Historical data from a study completed in 2018 by the United States Customs and Border Protection in which samples were collected at most of the same site locations (United States Customs and Border Protection, 2018). Border Patrol Study samples were taken during both wet weather and dry weather, so Water Quality Characterization data were compared as they apply (Table 2-7 and Table 2-8). Attachment D provides graphs with these data comparisons, also showing applicable Basin Plan WQOs for reference.

2.3.1 San Diego Basin Plan Data Comparisons
The San Diego Basin Plan (Basin Plan) WQOs establish thresholds/water quality standards applicable to discharges to inland surface waters, enclosed bays and estuaries considered protective of a range of beneficial uses. The beneficial uses applicable to Tijuana River Valley include recreation (REC-1 and REC-2), warm freshwater habitat (WARM) and wildlife habitat (WILD). Table 2-5 shows that most water quality characterization results exceeded applicable WQOs from the Basin Plan, notably for fecal coliform, E. coli, and Enterococcus. Specifically regarding TSS, the Tijuana River Valley is an area with known historical sediment pollution issues (USACE, 2018 and 2020); therefore, detectable levels of TSS are expected. TSS results for this study ranged from 24 – 21,600 mg/L for dry weather and 28 – 29,900 mg/L for wet weather. The TSS WQO from the Basin Plan for TSS is a narrative, stating that “Waters shall not contain suspended and settleable solids in concentrations of solids that cause nuisance or adversely affect beneficial uses.” While TSS results (especially at Goat Canyon) were high due to suspected sediment loading, other factors would need to be considered to confirm that the TSS levels were causing a nuisance to the beneficial uses that which apply to this water body.

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Table 2-5
Water Quality Characterization Results Comparison to Basin Plan WQOs Analyte Basin Plan
WQO
Applicable Basin
Plan Beneficial
Use Designation1
Number of Dry Weather
Exceedances of Basin Plan
WQO (out of 14 Samples)
Number of Wet Weather
Exceedances of Basin Plan
WQO (out of 14 Samples)
Dissolved Oxygen
(DO)
(mg/L)
>5 WARM 3 3
pH 6.5 – 8.5 None 0 6
Specific Conductivity
(mS/cm) NA NA NA NA
Temperature (ºC) NA NA NA NA
Oxidation Reduction
Potential (ORP)
(mV)

NA NA NA NA
Turbidity (NTU) <202 None 0 0
CBOD (mg/L) NA NA NA NA
TSS (mg/L) Narrative3 None NA NA
Total Coliform
(MPN/100mL) NA4,5 NA NA NA
Fecal Coliform
(MPN/100mL)
4,000
(SSM)4,6 REC-2 9 14
E. coli
(MPN/100mL) 320 (STV)4,7 REC-1 12 138
Enterococcus
(MPN/100mL) 110 (STV)4,9 REC-1 12 14
Notes:
°C = degrees Celsius; Basin Plan = San Diego Basin Plan (San Diego Water Board, 2008); CBOD = carbonaceous biochemical oxygen demand; DO = dissolved oxygen; E. coli = Escherichia coli; mg = milligrams; MPN/100mL = Most Probable Number per 100 milliliters; mS = millisiemens; mV = millivolts; NA = not applicable; NC = Not Collected; ORP = oxygen reduction potential; pH = Scale for potential of hydrogen; SSM = single sample maximum; STV = statistical threshold value; TSS = total suspended solids

1. The Tijuana River Valley (Inland Surface Waters) is listed as a current non-contact recreation (REC-2) beneficial use and potential contact recreation (REC-1) use in the revised San Diego Basin Plan (Adopted Chapter 3 Proposed Updates (ca.gov)).

2. WQO for Inland Surface Waters, San Ysidro HSA from Table 3-9 in San Diego Basin Plan

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Table 2-5 (continued)
Water Quality Characterization Results Comparison to Basin Plan WQOs

Analyte Basin Plan
WQO
Applicable Basin
Plan Beneficial
Use Designation1
Number of Dry Weather
Exceedances of Basin Plan
WQO (out of 14 Samples)
Number of Wet Weather
Exceedances of Basin Plan
WQO (out of 14 Samples)

3. Waters shall not contain suspended and settleable solids in concentrations of solids that cause nuisance or adversely affect beneficial uses. The Tijuana River Valley is an area where sediment is known to transport from upstream to downstream, therefore, some detectable levels of TSS are expected.

4. WQO for Inland Surface Waters

5. Total coliform WQOs are only listed for shellfish (SHELL) beneficial use water bodies in the revised San Diego Basin Plan.

Shellfish beneficial use WQOs do not apply to The Tijuana River or its tributaries.

6. Single-Sample Maximum Value in a 30-day period.

7. E. coli will be selected for analyses for all waters where the salinity is equal to or less than 1 ppt 95 percent or more of the time, and Enterococcus will be selected for analyses for all waters where the salinity is greater than 1 ppt more than 5 percent of the time. For all assessed waters, salinity was equal to or less than 1 ppt 95 percent or more of the time, so the E. Coli Basin Plan WQO is applicable for assessment.

8. During the data QA process, two WW2 Smuggler’s Gulch results were flagged. A lab error was suspected in these results.

Based on previous results, the magnitude of Total Coliform and E. Coli results are anticipated to match those of Fecal Coliform and Enterococcus. For the purposes of this study, these results were rejected and were not assessed against benchmarks.

9. STV not to be exceeded by more than 10% of the samples collected in a 30-day period.

2.3.2 MS4 Permit NAL and SAL Data Comparisons
NALs and SALs are action levels included in the MS4 Permit that are typically applied to outfall sampling results incorporated in the Water Quality Improvement Plan monitoring programs. As a point of reference, Water Quality Characterization results were compared to NALs and SALs from the MS4 Permit. Dry weather turbidity and fecal indicator bacteria results exceeded applicable NALs, and all but one wet weather turbidity result exceeded SALs.

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Table 2-6
Water Quality Characterization Results Comparison to MS4 Permit NALs and SALs Analyte MS4 Permit NAL
Number of Dry
Weather
Exceedances of MS4
Permit NAL
MS4 Permit SAL
Number of Wet
Weather
Exceedances of MS4
Permit SAL
Dissolved Oxygen
(DO) (mg/L) >5 for WARM1 3 NA NA
pH 6.5-8.51

6.0-9.02
0 NA NA
Specific Conductivity
(mS/cm) NA NA NA NA
Temperature (ºC) NA NA NA NA
Oxidation Reduction
Potential (ORP)
(mV)

NA NA NA NA
Turbidity (NTU) 201
2252,3 13 126 13
CBOD (mg/L) NA NA NA NA
TSS (mg/L) NA NA NA NA
Total Coliform
(MPN/100mL) NA NA NA NA
Fecal Coliform
(MPN/100mL)
2001,4
4002
13 NA NA
E. coli
(MPN/100mL) NA NA NA NA
Enterococcus
(MPN/100mL)
331
1042
13 NA NA
Notes:
°C = degrees Celsius; CBOD = carbonaceous biochemical oxygen demand; DO = dissolved oxygen; E. coli = Escherichia coli; mg = milligrams; MPN/100mL = Most Probable Number per 100 milliliters; mS = millisiemens; MS4 = municipal separate storm sewer system; mV = millivolts; NA = not applicable; NAL = Non-Storm Water Action Level ORP = oxygen reduction potential; pH = Scale for potential of hydrogen; SAL = Storm Water Action Level; TSS = total suspended solids

1. Applies to Inland Surface Waters

2. Applies to Bay, Harbor, Lagoons/Estuary waters

3. Instantaneous maximum

4. Minimum of not less than five samples for any 30-day period

2.3.3 Border Patrol Study Data Comparisons
The Border Patrol Study (United States Customs and Border Protection, 2018) presented average results at each site for dry weather and for wet weather conditions. Water Quality Characterization

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study results were separated by dry or wet weather, and averaged per site for the two monitoring events. Each average result was compared to Border Patrol Study results at the same site, each for dry and wet weather, to determine if it showed a better or worse condition than the Border Patrol Study result. It was determined to be a worse condition if:
• Dissolved Oxygen and ORP: Water Quality Characterization results were LOWER than Border Patrol Study results
• Specific Conductivity, Temperature, Turbidity, Indicator Bacteria: Water Quality Characterization results were HIGHER than Border Patrol Study results • pH: Not applicable
For dry weather, analytes whose concentrations resulted in a worse condition than Border Patrol Study results were dissolved oxygen and indicator bacteria, including fecal coliform, E. coli, and Enterococcus. For wet weather, all monitored analytes that were also monitored in the Border Patrol Study resulted in a worse condition than Border Patrol Study results including dissolved oxygen, specific conductivity, temperature, and ORP.

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Table 2-7
Water Quality Characterization Dry Weather Results Data Comparison to Border Patrol Study Results Location Yogurt
Canyon
Goat
Canyon
Smuggler’s
Gulch
Silva’s
Drain
Canyon del
Sol
Stewart’s
Drain
Tijuana
River Main
Channel
Number of Stations with
Average Dry Weather Results
Worse Condition Than Border
Patrol Study Results Analyte Dry Weather Border Patrol Study Results Dissolved
Oxygen (DO)
(mg/L)

10.96 6.31 24.00 NC NC 9.84 NC 3 (out of 4)
pH 7.57 7.58 6.10 NC NC 8.02 NC NA
Specific
Conductivity
(mS/cm)

10.08 4.56 1.20 NC NC 2.74 NC 1 (out of 4)
Temperature
(ºC) 19.83 17.99 8.40 NC NC 23.58 NC 2 (out of 4)
Oxidation
Reduction
Potential
(ORP)
(mV)
166.30 123.41 240.00 NC NC 172.01 NC 2 (out of 4)
Turbidity
(NTU) NC NC NC NC NC NC NC NA
CBOD (mg/L) NC NC NC NC NC NC NC NA
TSS (mg/L) NC NC NC NC NC NC NC NA

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Table 2-7 (continued)
Water Quality Characterization Dry Weather Results Data Comparison to Border Patrol Study Results

Location Yogurt
Canyon
Goat
Canyon
Smuggler’s
Gulch
Silva’s
Drain
Canyon del
Sol
Stewart’s
Drain
Tijuana
River Main
Channel
Number of Stations with
Average Dry Weather Results
Worse Condition Than Border
Patrol Study Results Analyte Dry Weather Border Patrol Study Results Total Coliform
(MPN/100mL) 401,393 1,891,379 1,767,000 NC 2,420,000 2,179,909 NC 4 (out of 5) Fecal
Coliform
(MPN/100mL)

NC NC NC NC NC NC NC NA
E. coli
(MPN/100mL) 587 1,715,127 1,648,333 NC 2,420,000 1,652,636 NC 3 (out of 5) Enterococcus
(MPN/100mL) 1,481 860,600 660,000 NC 500,000 929,091 NC 4 (out of 5) Notes:
°C = degrees Celsius; CBOD = carbonaceous biochemical oxygen demand; DO = dissolved oxygen; E. coli = Escherichia coli; mg = milligrams; MPN/100mL = Most Probable Number per 100 milliliters; mS = millisiemens; mV = millivolts; NA = not applicable; NC = Not Collected for Border Patrol Study; ORP = oxygen reduction potential; pH = Scale for potential of hydrogen; SSM = single sample maximum; STV = statistical threshold value; TSS = total suspended solids

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Table 2-8
Water Quality Characterization Wet Weather Results Data Comparison to Border Patrol Study Results Location Yogurt
Canyon
Goat
Canyon
Smuggler’s
Gulch
Silva’s
Drain
Canyon del
Sol
Stewart’s
Drain
Tijuana
River Main
Channel
Number of Stations
with Average Dry
Weather Results
Worse Condition Than
Border Patrol Study
Results
Analyte Wet Weather Border Patrol Study Results
Dissolved Oxygen
(DO) (mg/L) NC NC 11.41 NC 9.87 3.41 NC 3 (out of 3)
pH NC NC 8.43 NC 6.95 7.29 NC NA
Specific Conductivity
(mS/cm) NC NC 0.66 NC 0.69 0.80 NC 3 (out of 3)
Temperature (ºC) NC NC 14.99 NC 15.61 17.18 NC 3 (out of 3) Oxidation Reduction
Potential (ORP)
(mV)
NC NC 21.65 NC 65.20 74.10 NC 3 (out of 3)
Turbidity (NTU) NC NC NC NC NC NC NC NA
CBOD (mg/L) NC NC NC NC NC NC NC NA
TSS (mg/L) NC NC NC NC NC NC NC NA
Total Coliform
(MPN/100mL) NC NC NC NC NC NC NC NA

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Table 2-8 (continued)
Water Quality Characterization Wet Weather Results Data Comparison to Border Patrol Study Results

Location Yogurt
Canyon
Goat
Canyon
Smuggler’s
Gulch
Silva’s
Drain
Canyon del
Sol
Stewart’s
Drain
Tijuana
River Main
Channel
Number of Stations
with Average Dry
Weather Results
Worse Condition Than
Border Patrol Study
Results
Analyte Wet Weather Border Patrol Study Results
Fecal Coliform
(MPN/100mL) NC NC NC NC NC NC NC NA
E. coli
(MPN/100mL) NC NC NC NC NC NC NC NA
Enterococcus
(MPN/100mL) NC NC NC NC NC NC NC NA
Notes:
°C = degrees Celsius; CBOD = carbonaceous biochemical oxygen demand; DO = dissolved oxygen; E. coli = Escherichia coli; mg = milligrams; MPN/100mL = Most Probable Number per 100 milliliters; mS = millisiemens; mV = millivolts; NA = not applicable; NC = Not Collected for Border Patrol Study; ORP = oxygen reduction potential; pH = Scale for potential of hydrogen; SSM = single sample maximum; STV = statistical threshold value; TSS = total suspended solids

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

3.0 Sediment Characterization
Monitoring
Seven sediment source area locations were selected to characterize sediment deposition and makeup at the main river and canyon inputs to the Tijuana River and in the Tijuana River Valley.

Recent data were available for Tijuana River Estuary and Goat Canyon Sediment Basin Complex, so no additional monitoring was conducted at those sites. Dry weather monitoring occurred at the remaining five sites twice between October 2021 and January 2022.

The seven sites are representative of potential and existing sediment source areas throughout the Tijuana River Valley (Figure 3-1):
• Brown Fill Removal/Restoration Project;
• Flood Control Channel;
• Potential Basin Complex – Main Tijuana River;
• Potential Basin Complex – Smugglers;
• Smuggler’s Gulch/Pilot Channel;
• Tijuana River Estuary (existing data assessment); and • Goat Canyon Sediment Basin Complex (existing data assessment).

3.1 Sediment Characterization Monitoring Methods
Sediment was collected using a hand auger to a depth of approximately three feet from three locations within each sediment source area, as seen in Figure 3-1. All sediment collected were composited from each core, from the surface to the final depth. The contents were transferred to a clean pre-labeled container. After retrieval, the sediment samples from each site were transferred to a stainless-steel bowl and homogenized into one sample for each sediment source area. Samples were then transported to Physis Environmental Laboratories for analysis of chemical and physical properties.

3.2 Sediment Monitoring Results
Two dry weather monitoring events were performed at five monitoring locations on October 21, 2021 and January 7, 2022. Monitoring QA/QC results are presented in Attachment A. Full sediment monitoring result data tables can be found in Attachment E. Field data sheets for these sampling events are in Attachment F, and laboratory reports with results are in Attachment G.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

Figure 3-1
Evaluated Sediment Source Areas

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

3.2.1 Sediment Characterization Monitoring QA/QC Results Summary Sediment characterization data were compared with applicable measurement data quality objectives (MQOs) defined in the Monitoring Plan (Wood, 2021). Both field QA/QC samples (field duplicates and equipment blanks) and laboratory QA/QC samples (method blanks, lab duplicates, matrix spikes and duplicates, blank spikes and duplicates, laboratory control material, and certified reference material) were assessed against MQOs. Equipment blanks were performed to verify that handling of equipment, air deposition, and cleaning methods between sampling sites were not a source of contamination. They were performed by rinsing equipment with reagent grade DI water in the field during a sampling event into a container. Multiple issues were noted in the QA/QC samples: Fifteen field duplicate analytes exceeded the 25% RPD MQO, five metal analytes in the equipment blank exceeded the RL, four Semi-Volatile Organic Compounds in the method blank exceeded the RL for both events, forty-four lab duplicate analytes exceeded the 25% RPD MQO, N-Nitrosodiphenylamine and Cypermethrin matrix spike duplicates exceeded the 30% RPD MQO, and thirty-eight recovery MQOs were exceeded. Many of these analytes are organics, whose laboratory methods have a high sensitivity and could easily trigger MQO exceedances. While QA/QC issues were noted and discussed with the laboratory, they did not comprise the overall integrity of assessment results. See Attachment A for more information.

3.3 Sediment Characterization Monitoring Data Assessment The suite of analyses for Sediment Characterization sampling was developed based on testing requirements for the potential reuse opportunities identified for the project. The Dredged Material Proposed for Discharge in Waters of the US - Testing Manual (Inland Testing Manual) (USEPA, 1998) outlining testing procedures for dredged material or sediment intended to be reused for some of the reuse purposes was considered for development of the Monitoring Program. For example, beach replenishment focuses on physical properties more than chemical constituents, however, hazardous materials must still be shown as not being detected. The Sand Compatibility and Opportunistic Use Program (SCOUP) Plan (SANDAG, 2006) outlines regional requirements for sediment reuse and lists permits required for certain reuse types, including consideration of the characteristics of the receiving site.

The Monitoring Program was also designed to present results from multiple sediment sampling events, since runoff due to rainfall is known to transport sediment downstream and alter sediment source area composition. Figure 3-2 illustrates the timeline of the resulting Sediment Characterization sampling events and the rainfall events that occurred in between. The seven rainfall events seen in Figure 3-2 ranged from 0.04 - 1.20 inches over nine events during the Sediment Characterization sampling period.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

Figure 3-2
Sediment Characterization Sampling Timeline
To examine the resulting potential sediment reuse opportunities, it was first determined if sediments in the sampled locations potentially contained hazardous materials. To determine the hazardous nature of sediments, sample results were compared to Title 22 Section 66261.24 requirements. Sediment Characterization monitoring results were first compared to TTLC wet weight thresholds (mg/kg), as shown in Figure 3-3. If any analytes resulted in a concentration above the TTLC, the material was determined potentially hazardous, and would limit the reuse opportunities available from that sampled location. Sediment Characterization monitoring results were additionally compared against applicable soluble threshold limit concentration (STLC) and toxicity characteristic leaching procedure (TCLP) concentration (mg/L) thresholds, as seen in the Title 22 flowchart (Figure 3-3).

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

Figure 3-3
Flowchart for Hazardous Waste Determination under Title 22

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

As shown in Table 3-1, Sediment Characterization Monitoring results did not exceed any of the applicable TTLC, STLC, or TCLP benchmarks from Title 22 Section 66261.24. Table 3-2 describes the results of the hazardous material assessment by sampling location.

Table 3-1
Sediment Characterization Monitoring Comparison to Title 22 Benchmarks Constituent TTLC Benchmark
(mg/kg)
STLC Benchmark
(mg/L)
TCLP Benchmark
(mg/L)
Total Exceedances of
TTLC, STLC, or TCLP
Benchmarks
Antimony 500 15.0 NA 0
Arsenic 500 5.0 5.0 0
Barium 10,000 100 100 0
Beryllium 75 0.75 NA 0
Cadmium 100 1.0 1.0 0
Chromium 2,500 5.0 5.0 0
Cobalt 8,000 80 NA 0
Copper 2,500 25 NA 0
Lead 1,000 5.0 5.0 0
Mercury 20 0.2 0.2 0
Molybdenum 3,500 350 NA 0
Nickel 2,000 20 NA 0
Selenium 100 1.0 1.0 0
Silver 500 5.0 5.0 0
Thallium 700 7.0 NA 0
Vanadium 2,400 24 NA 0
Zinc 5,000 250 NA 0
2,4'-DDT 1.0 0.1 NA 0
2,4'-DDD 1.0 0.1 NA 0
2,4'-DDE 1.0 0.1 NA 0
4,4'-DDT 1.0 0.1 NA 0
4,4'-DDD 1.0 0.1 NA 0
4,4'-DDE 1.0 0.1 NA 0
Aldrin 1.4 0.14 NA 0
Chlordane-alpha 2.5 0.25 0.03 0
Chlordane-gamma 2.5 0.25 0.03 0
Dieldrin 8.0 0.8 NA 0
Endrin 0.2 0.02 0.02 0
Heptachlor 4.7 0.47 0.01 0
Kepone 21.0 2.1 NA 0

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
Table 3-1 (continued)
Sediment Characterization Monitoring Comparison to Title 22 Benchmarks

Constituent TTLC Benchmark
(mg/kg)
STLC Benchmark
(mg/L)
TCLP Benchmark
(mg/L)
Total Exceedances of
TTLC, STLC, or TCLP
Benchmarks
Lindane 4.0 0.4 0.4 0
Methoxychlor 100.0 10.0 10.0 0
Mirex 21.0 2.1 NA 0
Pentachlorophenol 17.0 1.7 100.0 0
Polychlorinated biphenyls
(PCBs)1

50.0 5.0 NA 0
Toxaphene 5.0 0.5 0.5 0
Trichloroethylene 2,040 204.0 0.5 0
Asbestos 1% NA NA 0
Total Exceedances 0
Notes:
% = percent; kg = kilogram; mg = milligrams; PCB = Polychlorinated biphenyls; STLC = Soluble Threshold Limit Concentration; TCLP = Toxicity Characteristic Leach Procedure; TTLC = total threshold limit concentration; NA = not applicable

1. For comparison to the TTLC benchmark, all 52 PCB Congeners analyzed were summed for the Total PCB concentration result.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

Table 3-2
Sediment Characterization Monitoring Hazardous Material Assessment by Location Site ID
Hazardous
Sediments
Present Based on
Assessment of
TTLC
Exceedances?
Hazardous
Sediments
Present Based on
Assessment of
STLC
Exceedances?
Hazardous
Sediments
Present Based on
Assessment of
TCLP
Exceedances?
Brown Fill Removal/Restoration Project
(BRWNFL)
No No No
Flood Control Channel
(FLDCHNL)
No No No
Potential Basin Complex – Main
Tijuana River
(BASINTJRVR)
No No No
Potential Basin Complex – Smugglers
(BASINSMGL)
No No No
Smuggler’s Gulch/Pilot Channel
(SMGLPILOT)
No No No
Notes:

ID = identification; STLC = Soluble Threshold Limit Concentration; TCLP = Toxicity Characteristic Leach Procedure; TTLC = Total Threshold Limit Concentration

3.4 Existing Sediment Data Assessment
The purpose of the existing data assessment performed was to use existing data to determine potential sediment reuse opportunities. Two recent studies provided comparable data (including similar analytes) to sediment data collected under this Monitoring Program; therefore, additional monitoring was not needed at these sites. The two studies evaluated included:
• Tijuana Estuary Tidal Restoration Program (TETRP) (The Bodhi Group, 2021). The TETRP report presents sediment sampling results from September 2020 within Border Field State Park in the southern part of the Tijuana Estuary • Goat Canyon Sediment Basins Clean Out and Removal of Deposition Material Report (ERRG, 2021). This report presents sediment sampling results from material dredged from the Goat Canyon Sediment Basins in May 2021.

Assessment of data from these two studies to evaluate potential sediment reuse opportunities was conducted by comparing results to the same Title 22 thresholds as summarized in Section 3.2.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

3.4.1 Estuary Sediment Characterization
The Tijuana Estuary Tidal Restoration Program (TETRP) report presents sediment sampling results from September 2020 within Border Field State Park in the southern part of the Tijuana Estuary. Average concentration results and comparisons to the same TTLC, STLC, and TCLP benchmarks as the Sediment Characterization Monitoring results are presented in Table 3-3.

Table 3-3
TETRP Report Results and Comparison to Title 22 Benchmarks Analyte
Average
Resulting
Concentration
(mg/kg)1
TTLC
Benchmark
(mg/kg)
STLC
Benchmark
(mg/L)
TCLP
Benchmark
(mg/L)
Total
Exceedances of
TTLC, STLC, or
TCLP
Benchmarks
Total Metals
Antimony 1.35 500 15 NA 0
Arsenic 2.61 500 5.0 5.0 0
Barium 157.04 10,000 100 100 0
Beryllium 0.50 75 0.75 NA 0
Cadmium 0.63 100 1.0 1.0 0
Chromium 12.27 2,500 5.0 5.0 0
Chromium,
Hexavalent 0.20 500 5.0 NA 0
Cobalt 5.50 8,000 80 NA 0
Copper 8.32 2,500 25 NA 0
Lead 4.25 1,000 5.0 5.0 0
Mercury 0.05 20 0.2 0.2 0
Molybdenum 0.74 3,500 350 NA 0
Nickel 5.55 2,000 20 NA 0
Selenium 0.63 100 1.0 1.0 0
Silver 0.63 500 5.0 5.0 0
Thallium 0.45 700 7.0 NA 0
Vanadium 34.53 2,400 24 NA 0
Zinc 42.14 5,000 250 NA 0
PCBs and PCB Mixtures
PCB-18 0.000123 50 5.0 NA 0
PCB-28 0.000123 50 5.0 NA 0
PCB-37 0.000123 50 5.0 NA 0
PCB-44 0.000123 50 5.0 NA 0
PCB-49 0.000123 50 5.0 NA 0
PCB-52 0.000123 50 5.0 NA 0
PCB-66 0.000123 50 5.0 NA 0
PCB-70 0.000123 50 5.0 NA 0
PCB-74 0.000123 50 5.0 NA 0
PCB-77 0.000123 50 5.0 NA 0
PCB-81 0.000123 50 5.0 NA 0

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
Table 3-3 (continued)
TETRP Report Results and Comparison to Title 22 Benchmarks

Analyte
Average
Resulting
Concentration
(mg/kg)1
TTLC
Benchmark
(mg/kg)
STLC
Benchmark
(mg/L)
TCLP
Benchmark
(mg/L)
Total
Exceedances of
TTLC, STLC, or
TCLP
Benchmarks
PCB-87 0.000123 50 5.0 NA 0
PCB-99 0.000123 50 5.0 NA 0
PCB-101 0.000123 50 5.0 NA 0
PCB-105 0.000123 50 5.0 NA 0
PCB-110 0.000123 50 5.0 NA 0
PCB-114 0.000123 50 5.0 NA 0
PCB-118 0.000123 50 5.0 NA 0
PCB-119 0.000123 50 5.0 NA 0
PCB-123 0.000123 50 5.0 NA 0
PCB-126 0.000123 50 5.0 NA 0
PCB-128 0.000123 50 5.0 NA 0
PCB-132/153 0.000246 50 5.0 NA 0
PCB-138/158 0.000246 50 5.0 NA 0
PCB-149 0.000123 50 5.0 NA 0
PCB-151 0.000123 50 5.0 NA 0
PCB-156 0.000123 50 5.0 NA 0
PCB-157 0.000123 50 5.0 NA 0
PCB-167 0.000123 50 5.0 NA 0
PCB-168 0.000123 50 5.0 NA 0
PCB-169 0.000123 50 5.0 NA 0
PCB-170 0.000123 50 5.0 NA 0
PCB-177 0.000123 50 5.0 NA 0
PCB-180 0.000123 50 5.0 NA 0
PCB-183 0.000123 50 5.0 NA 0
PCB-187 0.000123 50 5.0 NA 0
PCB-189 0.000123 50 5.0 NA 0
PCB-194 0.000123 50 5.0 NA 0
PCB-201 0.000123 50 5.0 NA 0
PCB-206 0.000123 50 5.0 NA 0
PCB-209 0.000123 50 5.0 NA 0
Aroclor -1016
Aroclor -1221
Aroclor -1232
Aroclor -1242
Aroclor -1248
Aroclor -1254
Aroclor -1260
Aroclor -1262
Aroclor -1268

0.005 50 5.0 NA 0

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
Table 3-3 (continued)
TETRP Report Results and Comparison to Title 22 Benchmarks

Analyte
Average
Resulting
Concentration
(mg/kg)1
TTLC
Benchmark
(mg/kg)
STLC
Benchmark
(mg/L)
TCLP
Benchmark
(mg/L)
Total
Exceedances of
TTLC, STLC, or
TCLP
Benchmarks
Total RMP 40 0.000246 50 5.0 NA 0
Pesticides & Herbicides
Aldrin 0.00062 1.4 0.14 NA 0
Chlordane 0.00314 2.5 0.25 0.03 0
4,4'-DDD 0.00062 1.0 0.1 NA 0
4,4'-DDE 0.00139 1.0 0.1 NA 0
4,4'-DDT 0.00048 1.0 0.1 NA 0
Dieldrin 0.00013 8.0 0.8 NA 0
Endrin 0.00062 0.2 0.02 0.2 0
Heptachlor 0.00062 4.7 0.47 0.008 0
Lindane (GammaBHC)

0.00062 4.0 0.4 0.4 0
Methoxychlor 0.00062 100 10.0 10.0 0
Toxaphene 0.00314 5.0 0.5 0.5 0
2,4,5-
Trichlorophenoxy
propionic acid
(Silvex)

0.00496 10 1.0 1.0
0 2,4-D 0.04964 100 10 10 0
VOCs & SVOCs
Benzene 0.00081 NA NA 0.5 0
Carbon Tetrachloride 0.00046 NA NA 0.5 0
Chlorobenzene 0.00046 NA NA 100 0
Chloroform 0.00046 NA NA 6 0
1,2-Dichloroethane 0.00046 NA NA 0.5 0
1,1-Dichloroethylene 0.00046 NA NA 0.7 0
Tetrachloroethylene 0.00046 NA NA 0.7 0
Trichloroethylene 0.00092 2040 204 0.5 0
Vinyl chloride 0.00046 NA NA 0.2 0
Cresols 0.7479 NA NA 200 0
1,4-Dichlorobenzene 0.25 NA NA 7.5 0
2,4-Dinitrotoluene 0.25 NA NA 0.13 0
Hexachlorobenzene 0.25 NA NA 0.13 0
Hexachloroethane 0.25 NA NA 3 0
Nitrobenzene 1 NA NA 2 0
Pentachlorophenol 1.25 17 1.7 100 0
Pyridine 0.25 NA NA 5 0
2,4,5-Trichlorophenol 0.25 NA NA 400 0
2,4,6-Trichlorophenol 0.25 NA NA 2 0

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
Table 3-3 (continued)
TETRP Report Results and Comparison to Title 22 Benchmarks

Analyte
Average
Resulting
Concentration
(mg/kg)1
TTLC
Benchmark
(mg/kg)
STLC
Benchmark
(mg/L)
TCLP
Benchmark
(mg/L)
Total
Exceedances of
TTLC, STLC, or
TCLP
Benchmarks
Total Exceedances 0 0 0
Notes:
kg = kilogram; mg = milligrams; NA = not applicable; PCB = Polychlorinated biphenyls; STLC = Soluble Threshold Limit Concentration; SVOCs = semi-volatile organic compounds; TCLP = Toxicity Characteristic Leach Procedure; TETRP = Tijuana Estuary Tidal Restoration Program; TTLC = total threshold limit concentration; VOCs = volatile organic compounds

1. In calculation of averages, where the result was Not Detected, the calculation used the Reporting Limit. Where a J flag qualifier was on the result, the actual qualified concentration was used for calculation.

In the data contained in the TETRP report, there were zero exceedances of the TTLC, STLC, or TCLP benchmarks, indicating that these sediment locations do not result in hazardous classification by the standards of Title 22 Section 66261.24 TTLC comparison.

3.4.2 Goat Canyon Sediment Characterization
Existing sediment characterization results from the Goat Canyon site were compared to results from dredged sediment stockpile sampling conducted May 17-19, 2021. Results of this assessment were also used to evaluate potential sediment reuse opportunities. Average concentration results from 44 dredged sediment stockpile samples and comparisons to the same TTLC, STLC, and TCLP benchmarks as the Sediment Characterization Monitoring results are presented in Table 3-4.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

Table 3-4
Goat Canyon Report Results and Comparison to Title 22 Benchmarks Analyte
Average
Resulting
Concentration
(mg/kg)1
TTLC
Benchmark
(mg/kg)
STLC
Benchmark
(mg/L)
TCLP
Benchmark
(mg/L)
Total
Exceedances of
TTLC, STLC, or
TCLP
Benchmarks
Total Metals
Antimony 0.23 500 15 NA 0
Arsenic 2.43 500 5 5 0
Barium 74.55 10000 100 100 0
Beryllium 0.18 75 0.75 NA 0
Cadmium 0.12 100 1 1 0
Chromium (III) 10.64 2500 5 5 0
Chromium (VI) 0.56 500 5 NA 0
Cobalt 3.45 8000 80 NA 0
Copper 9.13 2500 25 NA 0
Lead 4.73 1000 5 5 0
Mercury 0.05 20 0.2 0.2 0
Molybdenum 0.87 3500 350 NA 0
Nickel 4.40 2000 20 NA 0
Silver 0.13 500 5 5 0
Thallium 0.15 700 7 NA 0
Vanadium 27.35 2400 24 NA 0
Zinc 43.70 5000 250 NA 0
PCBs and PCB Mixtures
Aroclor-1260 0.01 50 5 NA 0
Pesticides & Herbicides
4,4'-DDT 0.012 1 0.1 NA 0
VOCs & SVOCs
Tetrachloroethylene
(Tetrachloroethene) 0.0022 NA NA 0.7 0
Notes:
kg = kilogram; mg = milligrams; NA = not applicable; PCB = Polychlorinated biphenyls; STLC = Soluble Threshold Limit Concentration; SVOCs = semi-volatile organic compounds; TCLP = Toxicity Characteristic Leach Procedure; TTLC = total threshold limit concentration; VOCs = volatile organic compounds

1. In calculation of averages, where the result was Not Detected, the calculation used the Reporting Limit. Where a J flag qualifier was on the result, the actual qualified concentration was used for calculation.

In the data contained in the Goat Canyon dredged sediment stockpile sampling report, there were zero exceedances of the Title 22 TTLC, STLC, or TCLP benchmarks, indicating that Goat Canyon sediment does not result in hazardous classification by the standards of Title 22 Section 66261.24 TTLC comparison.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

4.0 Trash Evaluations
The purpose of the trash evaluations is to characterize current trash conditions to help determine the potential for sediment reuse as part of projects and/or capital projects. Results were also assessed against any locations that resulted in potentially containing hazardous sediment from the Sediment Characterization sampling.

4.1 Trash Evaluation Methods
The method used to complete trash evaluations is also used for MS4 Permit (San Diego Water Board, 2015) compliance monitoring in the San Diego region. Trash evaluations were conducted to answer the following study questions:

1. At what level is trash present at the seven monitoring locations (low, moderate, high, very high)?

2. What types of trash are present (plastics, metals, hazardous waste, etc.) and at what relative percentages?

3. What effects do the trash levels have on the potential reuse of sediment? During trash evaluations, visual assessments provided a resulting trash category based on the following criteria (Figure 4-1):
• Trash Category: Low (1-3)
o On first glance, little or no trash is visible.
o One individual could easily remove all trash observed within 30 minutes. • Trash Category: Medium (4-6)
o Predominantly free of trash except for a few littered areas. o On average, all trash could be cleaned up by two individuals within 30 minutes to one hour.
• Trash Category: High (7-9)
o Predominantly littered except for a few clean areas. Evidence of site being used by people: scattered cans, bottles, food wrappers, plastic bags, etc. o On average, it would take a more organized effort (more than 2 people, but less than 5) to remove all trash from the area. Removal of trash would take 30 mins to 2 hours.
• Trash Category: Very High (10-12)
o Trash is continuously seen throughout the assessment area. Evidence of site being used frequently by people (e.g., many cans, bottles, food wrappers, plastic bags, clothing, piles of garbage and debris).
o On average, it would take a large number of people (more than 5) during an organized effort to remove all trash from the area. Removal of all trash would take more than 2 hours.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

Low Trash Category Example Medium Trash Category Example High Trash Category Example Very High Trash Category Example Figure 4-1
Trash Category Example Photos

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

4.2 Trash Evaluation Results
Trash evaluation data were successfully collected during the same two sampling events and at the same five sediment sources areas in coordination with Sediment Characterization Monitoring, plus the additional Goat Canyon Sediment Basin Complex site. Resulting trash levels for each event are presented in Table 4-1. Field data sheets for these trash evaluation events are in Attachment G.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

Table 4-1
Trash Evaluation Results
Site ID
Brown Fill Removal/
Restoration Project
BRWNFL
Flood Control
Channel

FLDCHNL
Potential Basin
Complex – Main
Tijuana River

BASINTJRVR
Potential Basin
Complex – Smugglers

BASINSMGL
Smuggler’s Gulch/Pilot
Channel

SMGLPILOT
Goat Canyon

GTBASIN
Event
Date 10/21/21 1/7/22 10/21/21 1/7/22 10/21/21 1/7/22 10/21/21 1/7/22 10/21/21 1/7/22 10/21/21 1/7/22 Is Trash
Visible No No Yes Yes No No Yes Yes Yes Yes Yes Yes
Resulting
Trash
Score
1 2 11 11 1 2 7 9 5 11 2 12
Level of
Trash1
Low Low Very High Very High Low Low High High Medium Very High Low Very High Types of
Trash None Plastic
Plastic Bags,
Bottles,
Polystyrene,
Paper/
Cardboard,
Cans
Plastic
Bags,
Bottles,
Cans,
Fabric,
Plastics
None Cigarette
Butts
Plastic
Bags,
Bottles,
Cans,
Plastics,
Wood
Plastic
Bags,
Bottles,
Cans,
Plastics,
Wood
Plastic
Bags,
Bottles,
Polystyrene,
Paper, Tires
Plastic Bags,
Bottles,
Polystyrene,
Plastics,
Wood
Plastic
Bags,
Fabric,
Tires
Cans,
Bottles,
Paper,
Plastics
Notes:

ID = identification

1. Trash Result Scores are grouped into categories: Low (1-3), Medium (4-6), High (7-9), Very High (10-12).

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

4.3 Trash Evaluation Data Assessment
Overall, the results indicated that trash levels were dependent on both upstream trash mobilization potential and maintenance responsibility in each sediment source area location.

Figure 4-2 presents the results by category as a percentage of the completed twelve evaluations.

Figure 4-2
Trash Evaluation Results
Trash evaluation results are mapped in Figure 4-3. Notable observations from the trash evaluations include:
• The Brown Fill Removal/Restoration Project site and the Potential Basin Complex – Main Tijuana River site are not in the downstream flow path of where trash would be mobilized.

Additionally, the County of San Diego and private agricultural owners are actively implementing maintenance programs that ensure that the areas are clean and free of trash.
• The Flood Control Channel site results were consistently the highest (score of 11 for event both assessments). This is likely caused by the large upstream drainage area, the magnitude of flow capable of mobilizing trash, and the location directly downstream of the channelized to natural channel transition.
• The Goat Canyon Sediment Basin Complex site received a Low score (2) during the October 21, 2021 assessment and then a Very High (12) score during the January 7, 2022 assessment. The Low score is suspected to be a result of the recent dredging of the sediment source area indicated by onsite Engineering/Remediation Resources Group, Inc. staff who met during the assessment (Wechsler, 2021). Between this assessment and the second assessment, wet weather events mobilized a large volume of trash that was caught behind the trash booms, likely resulting in a 12 (Very High) score. The normal trash condition at this site is expected to be higher than the first assessment.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

Figure 4-3
Trash Evaluation Results Map

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

5.0 Monitoring Program
Conclusion Summary
Results of the Monitoring Program are intended to guide potential management options for the reuse or disposal of sediment from source areas within the Tijuana River Valley. Water Quality Characterization, Sediment Characterization, and Trash Evaluation results were evaluated in conjunction with each other to draw conclusions about appropriateness of the potential sediment management options being considered for each sediment source area.

Water Quality Characterization results showed that most results exceeded Basin Plan WQOs, NALs, and SALs. Elevated CBOD levels were observed in both dry and wet weather. In raw sewage, levels of CBOD are typically above 200 mg/L (Metcalf and Eddy, Inc. 2003). Accordingly, Water Quality Characterization CBOD results indicate that raw sewage may have been present in dry weather at Goat Canyon, Silva’s Drain, Canyon del Sol, and Stewart’s Drain; and in wet weather at all seven sampling sites. Fecal indicator bacteria concentrations were also generally higher than the Border Patrol study results from 2018. High TSS levels were observed at most sampling locations, which aligns with known sedimentation issues in the Tijuana River Valley.

While TSS results do not provide an estimate of sediment deposition levels in the Tijuana River Valley, the modeling results of the USACE Phase I and II Hydrology, Floodplain, and Sediment Transport Reports (USACE, 2018 and 2020) conclude that 73% of the sediment in the 100-year flood event remains in the Tijuana River overbank instead of exiting to the ocean.

Sediment reuse and disposal opportunities being considered are:
• Beach and nearshore nourishment
• Thin-layer sediment addition
• Mine reclamation
• Construction material
• Levee rehabilitation
• Commercial landfill
• Remedial cap
• Landfill daily cover
• Upland landfill disposal
None of the Sediment Characterization monitoring samples exceeded Title 22 TTLC, STLC, or TCLP hazardous waste thresholds. Existing sediment characterization data at the Tijuana Estuary and Goat Canyon Sedimentation Basins yielded a similar conclusion of no exceedance of the same hazardous waste thresholds. Therefore, each of the sediment source areas evaluated for this project contain sediment that can potentially be reused for the reuse opportunities in Figure 5-1. However, permit applications for actual sediment reuse will require additional analysis.

California Code of Regulations (CCR) Title 22 Sections 66261.20 through 66261.24 require that waste be assessed for toxicity, ignitability, corrosivity, and reactivity to determine the hazardous nature of the waste prior to disposal.

Trash evaluations concluded that although there are some areas in the Tijuana River Basin where trash conditions are being maintained, high levels of trash are present at many locations, with the highest trash levels noted at the Goat Canyon and Flood Control Channel sediment source areas.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

As a result of the data assessments completed, the sampled sediment source areas were determined to have the Sediment Reuse Opportunities shown in Figure 5-1 and the sediment contained in these areas do have the potential to be used in future capital improvement projects.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

Figure 5-1
Potential Reuse Opportunity Results

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

6.0 References
The Bodhi Group. 2021. Sampling and Analysis Report, Tijuana Estuary Tidal Restoration Program II, Phase I. March 12, 2021.

Engineering/Remediation Resources Group (ERRG). 2021. Data Transmittal, Goat Canyon Sediment Basins Clean and Removal of Deposition Material. July 15, 2021.

Metcalf and Eddy, Inc. 2003. Wastewater Engineering: Treatment and Reuse. 4th Edition, McGraw-Hill, Inc., New York.

San Diego Water Board. 2008. Amendment to the Water Quality Control Plan for the San Diego Basin (Basin Plan) to Incorporate TMDL for Dissolved Copper, Lead, and Zinc in Chollas Creek, Tributary to San Diego Bay. Resolution No. 2008-00054. Approved July 15.

San Diego Water Board. 2015. Order Number R9-2013-0001, as amended by Order Nos. R9- 2015-0001 and R9-2015-0100. National Pollutant Discharge Elimination System Permit and Waste Discharge Requirements for Discharges from the Municipal Separate Storm Sewer System (MS4) Draining the Watersheds Within the San Diego Region. Retrieved from
https://www.waterboards.ca.gov/sandiego/water_issues/programs/stormwater/docs/2015 -1118_AmendedOrder_R9-2013-0001.pdf
SANDAG. 2006. Final Sand Compatibility and Opportunistic Use Program Plan. Prepared by Moffatt & Nichol. March 2006.
https://www.sandag.org/uploads/publicationid/publicationid_1203_5355.pdf USEPA. 1998. Evaluation of Dredged Material Proposed for Discharge in Waters of the US - Testing Manual. February 1998 https://www.epa.gov/sites/default/files/2015- 08/documents/inland_testing_manual_0.pdf.

United States Army Corps of Engineers (USACE). 2018. Phase I Hydrology, Floodplain, and Sediment Transport Report Final. Tijuana River, United States-Mexico International Border to the Pacific Ocean. September, 2018.

USACE. 2020. Phase 2 Hydrology, Floodplain, and Sediment Transport Report Final. Tijuana River, United States-Mexico International Border to the Pacific Ocean. December, 2020.

United States Customs and Border Protection. 2018. Tijuana Water Quality Analysis: Sampling Period January through June 2018.
https://www.waterboards.ca.gov/sandiego/board_info/agendas/2019/mar/item8/Item8_S D1_TijuanaTransboundarySummary.pdf

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

Wechsler, Charles. 2021. Engineering/Remediation Resources Group, Inc. Personal Interview.

October 21, 2021.

Wood. 2021. Tijuana River Valley Sediment Management Plan and Monitoring Program:

Monitoring Plan. September 2021.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

ATTACHMENT A
QA/QC Results for Water Quality and Sediment Characterization Monitoring

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
Introduction
This section addresses quality assurance/ quality control (QA/QC) activities for the Tijuana River Valley Sediment Management Plan and Monitoring Program. Both water quality and sediment data were compared with applicable measurement quality objectives (MQOs) defined in the Monitoring Plan (Wood, 2021). MQOs are quantitative and qualitative statements that define project objectives and specify the acceptable ranges of field sampling and laboratory performance. Results that do not meet MQOs are qualified and may be considered estimates.

MQOs for this project include objectives for precision, frequency, accuracy, and completeness.

For water quality characterization monitoring, field duplicate and field blank QA/QC samples were collected during monitoring. For sediment characterization monitoring, field duplicate and equipment blank QA/QC samples were collected during monitoring.

Field duplicates measure precision and evaluate the error introduced by field sampling. Duplicate samples consist of two replicates (an original and a duplicate) of the same matrix collected simultaneously and location using the same sampling techniques. The project frequency defined for field duplicates is at least 5% of the total sample count. The relative percent difference (RPD) is calculated to determine the precision between duplicate samples. The MQO for the sediment Field Blank sample was an RPD range between 0-25%. This calculation is as follows:
where: abs is the absolute value
x1 is measurement 1 (primary sample)
x2 is measurement 2 (e.g., duplicate sample)
Field blanks verify that field conditions, field sampling activities, and air deposition are not sources of contamination. Field blanks for water quality sampling were taken by filling sample bottles with reagent grade, analyte-free deionized (DI) water in the field during sampling events. The samples were then submitted blindly to the laboratory for analysis. The project frequency defined for field blanks is at least 5% of the total sample count. Field blanks for sediment samples were not collected due to cost prohibitions for the project.

Equipment blanks verify that handling of equipment and air deposition and cleaning methods between sampling sites are not sources of contamination. Equipment blanks will be taken by rinsing equipment with reagent grade, analyte-free DI water in the field during a sampling event into a container. The containers were then be submitted blindly to the laboratory for analysis of total metals, nutrients, and Oil and Grease. The MQO for the sediment equipment blank analysis was a concentration below the reporting limit for each analyte.

Additionally, laboratory QA/QC samples were assessed to provide information on potential laboratory contamination, analytical precision, and accuracy. Laboratory replicates, method blanks, and standard reference material (SRM) samples were assessed as part of this QA/QC program per the Monitoring Plan (Wood, 2021). Laboratory replicates were evaluated against a 25% RPD MQO, method blanks were evaluated against a less than their reporting limit MQO, and SRM samples were evaluated against analyte-specific % recovery MQOs.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
Quality Assurance/Quality Control of Water Quality Characterization Data All project samples required to be collected were collected, meeting the 90% completeness MQO.

All samples collected were analyzed within their holding times. Field duplicates and field blanks were analyzed at a total program frequency of 6 percent, which met the MQO minimum frequency required of 5 percent of all samples. Lab QA data also met the 5% MQO minimum frequency required.

Table A-1
Water Quality Characterization Quality Assurance/Quality Control Summary QA/QC
Summary
Field Data Exceedances of MQOs Lab QA Data Exceedances of MQOs Field Duplicate
RPD1
Field Blank
Detections >RL
Method Blank
Detection >RL LD RPD SRM % Recovery
Total QA/QC
Issues 1 1 0 0 0
Total Number of
Results 12 12 11 9 9
Percentage of
Data with
QA/QC Issues
8% 8% 0% 0% 0%
Notes:
% = Percent; LD = laboratory duplicate; MQO = measurement quality objective; QA = quality assurance; QC = quality control; RL = reporting limit; RPD = relative percent difference; SRM = standard reference material

1. MQO for field duplicates is RPD = 0–25.

The field duplicate for CBOD had an RPD of 33%, which did not meet the MQO of <25% RPD.

Additionally, the field blank for CBOD resulted in a concentration of 11.5 mg/L, which was above the RL of 2 mg/L. These minority occurrences of QA/QC exceedances do not compromise the overall integrity of assessment results.

Quality Assurance/Quality Control of Sediment Characterization Data All project samples required to be collected were collected, meeting the 90% completeness MQO.

All samples collected were analyzed within their holding times. Field duplicates and equipment blanks were analyzed at a total program frequency of 10 and 9 percent, respectively, which met the MQO minimum frequency required of 5% of all samples. Lab QA data also met the 5% MQO minimum frequency required.

For event 1, the radiometric recovery for the matrix spike (MS) of sample 2110635-6 is below the lower control limit of 70% at 63.1% for gross alpha and 66.4% for gross beta. For method Environmental Protection Agency (EPA) 8015M, low recoveries were observed for diesel C10- C28 in the matrix spike/ matrix spike duplicate (MS/MSD) of 2021-E1-BASINMGL the laboratory control sample (LCS) was within limits, the associated RPD was within limits, and these low recoveries were not associated with any reported results. Samples in method EPA 8015M, 2021- E1-BRWNFL-01 were diluted due to the dark color of the sample extract. For method GC/MS (EPA 8260B), Methylene chloride was detected between the MDL and the reporting limit (RL) in the method blank for batch 276649; this analyte was not detected in samples at or above the RL.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022
For event 2, the method blank result associated with batch 180-385118 for BOD analysis was higher than the method-required limit of 0.2 mg/L. Additionally, test replicates showed >30% RPD between the highest and lowest replicate for the Potential Basin Complex – Smugglers sample.

For this event Iron (Fe) was above the specified acceptance limits for the CRM. This occurred as a result of a more rigorous digestion employed by Physis, which causes a higher yield for some lithogenous elements. These values agree with Physis’ past internal results for CRM - ERA D099- 540. The radiometric recovery for the matrix spike of sample 2201113-4 was below the lower control limit of 70% at 48.5% for gross alpha and 64.7% for gross beta. For method EPA 8260B, Methylene chloride was detected above the RL in the method blank for batch 281621; this analyte was not detected in samples at or above the RL. Methylene chloride was detected between the MDL and the RL in the method blank for batch 281699.

Table A-2
Sediment Characterization Quality Assurance/Quality Control Summary QA/QC
Summary
Analytical Data Lab QA Data Exceedances of MQOs
Field
Duplicate
RPD1
Equipment
Blank
Detections
>RL
Method
Blank
Detection
>RL
LD RPD MSD and

BSD RPD

BS, BSD,

CRM, LCM,
MS, MSD %
Recovery
Total QA/QC
Issues 15 5 8 44 2 38
Total Number of
Results 240 27 501 317 736 1742
Percentage of
Data with
QA/QC Issues
6% 19% 2% 14% 0% 2%
Notes:
% = Percent; BS = blank spike; BSD = blank spike duplicate; CRM = certified reference material; LCM = laboratory control material; LD = laboratory duplicate; MQO = Measurement quality objective; MS = matrix spike; MSD = matrix spike duplicate; QA = quality assurance; QC = quality control; RL = reporting limit; RPD = relative percent difference

1. MQO for field duplicates is RPD = 0–25.

These minority occurrences of QA/QC exceedances do not compromise the overall integrity of assessment results.

Tijuana River Valley Sediment Management Plan and Monitoring Program Technical Results Memorandum
July 2022

ATTACHMENT B
Field Data Sheets (FDS) for Water Quality Characterization Monitoring