RFB - TIJUANA RIVER VALLEY HABITAT RESTORATION PROJECT (PHASE I AND PHASE II)

Tijuana River Valley Invasive
Species Removal and
Restoration
Execution Plan - Campground
October 2025 | 00187.00133.025
Prepared for:
County of San Diego
Department of Parks and Recreation
5510 Overland Avenue, Suite 270
San Diego, CA 92123
Prepared by:
HELIX Environmental Planning, Inc.
7578 El Cajon Boulevard
La Mesa, CA 91942

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TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION ................................................................................................................................ 1
2.0 PRE-RESTORATION VERIFICATION ................................................................................................... 1
3.0 SOIL SAMPLING RESULTS ................................................................................................................. 2
3.1 Soil Samples 1 and 2 ........................................................................................................... 3
3.2 Soil Samples 3 and 4 ........................................................................................................... 4
4.0 METHODS ......................................................................................................................................... 4
5.0 INVASIVE NON-NATIVE PLANT TREATMENT METHODS ................................................................ 15
6.0 PLANT AND SEED PALETTE ............................................................................................................. 17
7.0 EXPECTED RESTORATION OUTCOMES ........................................................................................... 22
8.0 APPLICABLE MITIGATION MEASURES ............................................................................................ 22
9.0 REFERENCES ................................................................................................................................... 25
LIST OF APPENDICES
A Soil Sample Test Results
B Success Criteria
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TABLE OF CONTENTS (cont.)
LIST OF FIGURES
No. Title Follows Page
1 Regional Location ............................................................................................................................. 2
2 USGS Topography ............................................................................................................................ 2
3 Aerial Photograph ............................................................................................................................ 2
4 Vegetation Communities/Habitats (Holland Oberbauer) ................................................................ 2
5 Restoration Plan ............................................................................................................................... 2
LIST OF TABLES
No. Title Page
1 Soil Sample Test Results Summary .................................................................................................. 2
2 Background Information .................................................................................................................. 4
3 Upland Restoration Methods .......................................................................................................... 4
4 Upland Enhancement Methods ..................................................................................................... 10
5 Control Methods for Invasive Non-Native Plants Likely to Occur in the Project Area .................. 15
6 Coastal Scrub Restoration Plant and Seed Palette - Priority 1 ...................................................... 18
7 Upland Enhancement Seed Palette - Priority 1 ............................................................................. 19
8 Coastal Scrub Restoration Plant and Seed Palette - Priority 2 ...................................................... 20
9 Upland Enhancement Seed Palette - Priority 2 ............................................................................. 21
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ACRONYMS AND ABBREVIATIONS
County County of San Diego
DPR Department of Parks and Recreation
EP Execution Plan
HELIX HELIX Environmental Planning, Inc.
HRP Habitat Restoration Plan
lbs. pounds
MM Mitigation Measure
TRVRP Tijuana River Valley Regional Park
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Tijuana River Valley Invasive Species Removal and Restoration - Campground Execution Plan | October 2025
1.0 INTRODUCTION
The Tijuana River Valley Invasive Species Removal and Restoration project created a Habitat Restoration
Plan (HRP; HELIX 2024a) that would serve as a guidance document for a broad-scale maintenance and
monitoring program for the restoration of approximately 595 acres of disturbed habitats within the
Tijuana River Valley Regional Park (TRVRP) that are County of San Diego (County)-owned and managed
by County Department of Parks and Recreation (DPR). Due to the size and scope of this overall
restoration program, the HRP assumes that restoration efforts would be initiated in smaller manageable
portions (phases), as funding allows and over the course of several years. The HRP stipulates that prior
to each phase, a brief Execution Plan would be prepared, describing the means and methods of
restoration practices that would be implemented for that phase of the restoration project being
implemented. The Execution Plans would select from the broad methodologies presented in the HRP
and provide specificity to implementation practices, methods, and expected project outcomes for that
project phase.
This report is an Execution Plan (EP) for the Campground Property (Assessor's Parcel Number 663-011-
1200). The Campground Property is located at 1942 Monument Road in the southwestern portion of the
TRVRP, within the HRP's Treatment Area 12 (Figure 1, Regional Location; Figure 2, USGS Topography;
and Figure 3, Aerial Photograph).
This EP provides details for the implementation, maintenance, and monitoring plan for restoration and
enhancement of habitat currently dominated by non-native and invasive non-native plants. The goal of
this EP is to restore native upland habitat to an area of the TRVRP that has been subject to disturbance
and has become dominated by invasive non-native plants. Implementation is anticipated to begin in Fall
2025, and within three years following implementation, the Campground Property is expected to be
approaching the functions and values of adjacent, preserved native upland habitat located within the
TRVRP. The Campground Property contains portions of the formal TRVRP trail network that will not be
restored.
2.0 PRE-RESTORATION VERIFICATION
HELIX biologists Pete Tomsovic, Benjamin Rosenbaum, and Jonathan Mercado conducted a general
biological field survey of the Campground Property on December 18, 2024. The biological field survey
confirmed that conditions have not changed substantially from previously mapped conditions (HELIX
2024a). Where conditions had changed, adjustments were made (Figure 4, Vegetation
Communities/Habitats [Holland Oberbauer]). The survey determined the restoration potential of
approximately 8.1 acres of coastal scrub habitat within habitat currently dominated by non-native and
invasive non-native plants and the enhancement of approximately 7.5 additional acres of native upland
habitat with a minor amount of non-native and invasive non-native plants (Figure 5, Restoration Plan).
In its current state, the Campground Property contains areas of disturbed habitat predominantly
consisting of invasive non-native plants, including five-hook bassia (Bassia hyssopifolia) and castor bean
(Ricinus communis), as represented in photographs below.
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Tijuana River Valley Invasive Species Removal and Restoration - Campground Execution Plan | October 2025
The western portion of the upland restoration area, facing southeast (left); and the northeastern portion of the
upland restoration area, facing southeast (right).
3.0 SOIL SAMPLING RESULTS
Three soil types have been mapped on-site: Chino silt loam, 0 to 2 percent slopes; Terrace escarpments;
and Visalia sandy loam, 0 to 2 percent slopes. Chino soils are moderately well-drained fine sandy loams
derived mainly from granitic alluvium. Soils in the Chino series occur on alluvial fans and terraces and
are frequently used as pasture and farmland. Chino series soils are not hydric soils, but have the
potential to contain unnamed hydric inclusions on alluvial fans. Terrace escarpments are steep to very
steep escarpments and similar landforms that occur on the fronts of terraces or alluvial fans. Terrace
escarpments soils formed in variable alluvium on terraces or barrancas and may have exposed gravel,
cobblestones, stones, or large boulders. Terrace escarpments are not hydric soils. Visalia soils are
moderately well-drained, very deep sandy loams, derived from granitic alluvium. Visalia soils occur on
alluvial fans and flood plains. Visalia series soils are not hydric soils, but the Visalia map unit is identified
as having the potential to contain unnamed hydric inclusions on floodplains (HELIX 2023).
Two surface and two sub-surface soil samples were collected during the general biological field survey
on December 18, 2024 (Figure 5). Approximately one quart of soil was collected per sampling location,
placed in a sealable plastic bag, and submitted to the testing laboratory, Waypoint Analytical, which
performed an A17 nutrient soil analysis, provided recommendations for soil amendments, if needed,
and performed an agricultural suitability analysis for native plants.
The full results of the soils testing are included in Appendix A, Soils Test Results. A summary of test
results is shown below in Table 1, Soil Sample Test Results Summary.
Table 1
SOIL SAMPLE TEST RESULTS SUMMARY
Test Sample 1 Surface Sample 2 Sub Surface Sample 3 Surface Sample 4 Sub Surface
Salinity high high high high
SAR high high high sufficient
Boron high high high sufficient
Sodium high high high sufficient
pH low alkaline moderately alkaline optimum optimum
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