PAGC_2025_Remedial_Wetland_Mitigation_Plan_09122025.pdf

720 University Avenue, Suite 200 Los Gatos, CA 95032 408.458.3200 www.harveyecology.com

Palo Alto Municipal Golf Course Reconfiguration Project

Remedial Wetland Mitigation Plan

Project #4821-02

Prepared for:

Lam Do City of Palo Alto

250 Hamilton Avenue Palo Alto, CA 94301

Prepared by:

H. T. Harvey & Associates

September 12, 2025 http://www.harveyecology.com/

Palo Alto Municipal Golf Course Reconfiguration Project Remedial Wetland Mitigation Plan i H. T. Harvey & Associates

Table of Contents

Section 1. Introduction

1.1 Permit Numbers

1.2 Report Purpose

1.3 Deed Restriction

1.4 Regulatory Agency Request

1.5 Project Background and Mitigation Requirements

1.6 Adequacy of Mitigation Acreage Provided

1.7 2024 Existing Conditions

1.8 Overview of Recommended Remedial Wetland Mitigation

Section 2. Remedial Actions

2.1 Overview

2.2 Construction Schedule and Quality Control

2.3 Trail Decommissioning through Wetlands

2.4 Removal of Invasive Plant Species

2.4.1 Ice Plant

2.4.2 Paspalum Turf Ecosystems (TE)

2.4.3 Greater Periwinkle

2.4.4 Russian Thistle

2.4.5 Perennial Pepperweed

2.4.6 Seeding Plan

2.5 Hydrologic Modifications

2.5.1 Wetland Group 1

2.5.2 Wetland Group 2

2.5.3 Wetland Group 6

2.6 Revegetation to Increase Species Richness and Native Cover

2.6.1 Overview

2.6.2 Seeding Plan

2.6.3 Container Plant Installation Plan

2.6.4 Maintenance Plan

Section 3. Modification to Success Criteria Section 4. Monitoring And Adaptive Management Section 5. Next Steps Section 6. Literature Cited

Figures

Figure 1. Vicinity Map Figure 2. Mitigation Wetlands Figure 3. Remedial Wetland Mitigation Actions

Tables

Table 1. Compensatory Wetland Mitigation Quantities Table 2. Summary of USACE and RWQCB Jurisdictional Wetlands within the Study Area

Project Remedial Wetland Mitigation Plan ii H. T. Harvey & Associates

Table 3. Summary of Mitigation and Monitoring Plan Performance Criteria Met by Wetland Group in 2024 8

Table 4. Seed Mix for Restoration of Trails through Wetlands Table 5. Seed Mix for Alkali Seasonal Wetlands Table 6. Seasonal Wetland Revegetation in Wetland Groups to Increase Species Richness and Cover Table 7. Container Plant Installation Palette

Appendices

Appendix A. Absolute Cover by Wetland Group and Species from 2024 Existing Conditions Report.... A-1 Appendix B. Photos of the Mitigation Wetlands from 2024 ............................................................................ B-1

List of Preparers

Max Busnardo, M.S., Principal-in-Charge, Senior Restoration Ecologist Gavin Archbald, M.S., Project Manager, Senior Restoration Ecologist

Project Remedial Wetland Mitigation Plan 1 H. T. Harvey & Associates

Section 1. Introduction

1.1 Permit Numbers

• Regional Water Quality Control Board (RWQCB) Water Quality Certification Site No. 02-01-C0698 [bkw], California Integrated Water Quality System Place No. 802332]

• U.S. Army Corps of Engineers (USACE) File No. 2013-00109S

1.2 Report Purpose

H. T. Harvey & Associates (H. T. Harvey) restoration ecologists prepared this report to provide a remedial wetland mitigation plan to the City of Palo Alto (City) for the 8.48-acre (ac) mitigation wetlands constructed at the Baylands Golf Links golf course. The wetlands were constructed by the City to mitigate for impacts to wetlands from the City’s Municipal Golf Course Reconfiguration Project (project). H. T. Harvey recommends the City begin implementing these remedial actions in August 2025 to avoid the possibility of the project incurring additional wetland mitigation acreage requirements per RWQCB permit Condition 33 (see Section 1.4). This report documents the City’s proposed maintenance actions in 2025 and 2026 to help the mitigation wetlands meet their final success criteria related to vegetation community composition.

This report also provides a summary of the annual monitoring methods the City proposes to use in Years 1-5.

The monitoring methods are based on the project’s Mitigation and Monitoring Plan (MMP; ICF International 2016) and the revised monitoring methodology approved for the project by RWQCB in 2024. In addition, we propose that the frequency of hydrology monitoring be reduced from the requirements in the MMP and that no further hydric soils monitoring be required, since a wetland delineation has now been completed (H. T.

Harvey & Associates 2025).

1.3 Deed Restriction

Condition 32 in the project’s RWQCB 401 certification requires that the City record a deed restriction over the mitigation wetlands. The City was awaiting completion of the wetland delineation prior to officially recording the deed restriction, so that the deed restriction accurately reflects the footprint of delineated mitigation wetlands. The City intends to complete the deed restriction recordation by December 31, 2025.

1.4 Regulatory Agency Request

The City requests that the RWQCB:

Project Remedial Wetland Mitigation Plan 2 H. T. Harvey & Associates

• Confirm that completing the required deed restriction on the mitigation wetlands in 2025 coupled with implementing the remedial actions in this plan will allow the City to begin the required 5-year monitoring period for the mitigation wetlands with Year 1 starting in 2026.

• Respond to the proposed modification to success criteria in Section 3.

• Respond to the proposed modification to monitoring methods in Section 4.

1.5 Project Background and Mitigation Requirements

The City constructed the project in 2016 and 2017 at the Baylands Golf Links golf course located at 1875 Embarcadero Road in Palo Alto, California (Figure 1). Reconfiguration of the golf course required 0.29 acres

(ac) of permanent and 1.36 ac of temporary impacts to wetlands/waters of the United States and State (non-tidal brackish marsh). The project’s permits and Mitigation and Monitoring Plan MMP require at least 4.0 ac of on-site wetland expansion (i.e., wetland creation) and 0.20 ac of on-site wetland enhancement to compensate for the project’s impacts (ICF International 2016).

The plan to expand and enhance the project wetlands is provided in the project’s MMP (ICF International 2016). The plan included 8.03 ac of wetland expansion and 0.42 of enhancement of existing wetlands at the golf course project site, exceeding the minimum permit required mitigation acreage by 100%. The RWQCB permit states (on Page 4) that, “Of the 8.03 acres of wetlands that the Applicant proposes to expand and the

0.42 acres that the Applicant proposes to enhance, 4 acres of expansion and 0.20 acres of enhancement are required to compensate for the Project’s impacts to waters of the State. Additional acres of expanded or enhanced wetlands may be used to provide for any additional mitigation required by Condition 33.”

The City implemented grading and planting to expand and enhance the wetland habitat in 2016 and 2017 (City of Palo Alto 2016; Wadsworth Golf Construction Company 2016, 2018). Wetland expansion included excavating fill from elevated terrain surrounding existing wetlands (approximately 2 feet of excavation), while wetland enhancement included invasive species removal (ICF International 2016). Both expanded and enhanced wetlands were then hydroseeded and planted with native brackish marsh plant species such as brown-headed rush (Juncus phaeocephalus), slough sedge (Carex obnupta), and meadow barley (Hordeum brachyantherum).

The project’s permits and MMP call for a minimum of 5 years of habitat monitoring of the expanded and enhanced wetlands (hereafter referred to as mitigation wetlands). Since the wetland expansion/enhancement occurred in 2016 and 2017, mitigation monitoring was required in 2017 through 2021. However, the City did not perform the annual monitoring.

Condition 33 of the RWQCB permit requires additional wetland mitigation as follows: “For any of the mitigation wetlands that fail to attain or maintain performance standards, or fail to have a deed restriction executed, the Applicant shall provide mitigation equivalent to the originally required mitigation, plus an additional 10 percent increase in the area of mitigation for each year between the initial discharge to waters of the State and the implementation of additional mitigation.” Per Condition 33 of the RWQCB permit, the amount of mitigation is required to increase by 10% for each year that successful implementation of mitigation was deferred. In this case, the correct acreage of wetlands was constructed, but

Project Remedial Wetland Mitigation Plan 3 H. T. Harvey & Associates no deed restriction was completed and the maintenance and monitoring necessary to attain performance standards was not completed.

Laurel Elementary

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Lorelei Manor Suburban Park

Allied Arts Stanford Park

Friendly Acres

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Stanford University

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Palo Alto Municipal Golf Course Reconfiguration Project Remedial Wetland Mitigation Plan (4821-02)

September 2025

Figure 1. Vicinity Map

Project Vicinity

California

Project Location

Project Remedial Wetland Mitigation Plan 5 H. T. Harvey & Associates

The additional mitigation required by the City per Condition 33 is calculated as follows. The initial discharge to waters of the U.S./State occurred in 2016. Year 1 monitoring was required in 2017 and at the end of 2025, 9 years will have passed without wetland habitat maintenance necessary to attain performance standards.

Therefore, a 90% increase in wetland mitigation area is required through 2025. The project’s USACE and RWQCB permits require at least 4.0 ac of wetland expansion (i.e., wetland creation) and 0.20 ac of wetland enhancement to compensate for the project’s impacts. Therefore, the RWQCB wetland mitigation acreage requirement in 2025 is as follows: 4.00 + (4.00 × 0.9) = 7.60 ac of wetland expansion (i.e., wetland creation) and 0.2 + (0.2 x 0.9) = 0.38 ac of wetland enhancement (Table 1).

Table 1. Compensatory Wetland Mitigation Quantities

Mitigation Type Initial Mitigation Acreage

Requirement (Acres) Revised RWQCB Mitigation

Acreage Requirement1 (Acres)

Expansion (Creation/Establishment) 4.00 7.60

Enhancement 0.20 0.38

Total 4.20 7.98 1 Per Regional Water Quality Control Board (RWQCB) permit condition 33, the amount of mitigation is required to increase by 10% for each year that successful implementation of mitigation (i.e., proper monitoring and maintenance) is deferred after the initial discharge to Waters of the U.S./State. The initial discharge occurred in 2016.

Therefore, a 90% increase in wetland mitigation area is required in 2025.

Additionally, the project’s MMP and USACE permit call for a wetland delineation in Year 1, while the project’s RWQCB permit calls for a wetland delineation in Year 5, to determine whether the mitigation wetland acreage sufficiently compensates for project impacts. This wetland delineation was completed in 2025 (H. T. Harvey 2025). The delineation identified approximately 8.48 ac of jurisdictional wetlands regulated by RWQCB and USACE among the golf course mitigation wetlands (Figure 2). Of the 8.48 ac, the expanded wetland areas accounted for 8.13 ac and 0.35 ac were pre-project wetlands that were enhanced by the project (Table 1). The acreage of wetland present by habitat type are provided in Table 2.

Wetland Group 1

Wetland Group 4

Wetland Group 5

Wetland Group 6

Wetland Group 3

Wetland Group 2

PP-16

PP-15

PP-1

PP-3

PP-4

PP-2

PP-5

PP-6

PP-8

PP-7

PP-9

PP-11

PP-10

PP-12

PP-13

PP-14

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Feet± Figure 2. Mitigation Wetlands

Palo Alto Municipal Golf Course Reconfiguration Project - Remedial Wetland Mitigation Plan (4821-02) September 2025

Mitigation Wetlands (8.48 ac)

Expanded Wetlands (8.13 ac)1

Enhanced Wetlands (0.35 ac)

Pre-existing Wetlands2

Photo Point

1. H.T. Harvey & Associates 2025. Palo Alto Municipal Golf Course Reconfiguration Project Jurisdictional Wetland Delineation. Los Gatos, CA. Prepared for City of Palo Alto

2. ICF International 2016. Palo Alto Municipal Golf Course Reconfiguration Project Mitigation and Monitoring Plan. Prepared for City of Palo Alto June 14.

Project Remedial Wetland Mitigation Plan 7 H. T. Harvey & Associates

Table 2. Summary of USACE and RWQCB Jurisdictional Wetlands within the Study Area

Habitat Type Acres

Brackish Marsh 0.13

Non-Tidal Salt Marsh 5.83

Seasonal Wetland 2.53

Total Section 404/401 Wetlands 8.481

Total Section 404/401 Wetlands within Expanded Wetland Area 8.13

Total Section 404/401 Wetlands within Enhanced Wetland Area 0.35 1 Totals do not sum correctly to the 0.01th acre due to rounding error.

Definitions: USACE = U.S. Army Corps of Engineers; RWQCB = Regional Water Quality Control Board

1.6 Adequacy of Mitigation Acreage Provided

The delineation report concluded that the RWQCB wetland mitigation acreage requirement of at least 7.60 ac of expanded wetlands was exceeded, since 8.13 ac were created onsite.

However, the RWQCB enhanced wetland mitigation acreage requirement of at least 0.38 ac was not met (0.35 ac enhanced onsite), indicating that 0.03 ac of enhanced wetlands (pre-existing wetlands) are no longer wetlands (Table 1). H. T. Harvey interpreted that as a project impact. The project initially required a 3:1 mitigation ratio to offset permanent impacts. Therefore, H. T. Harvey judged that an additional 0.09 ac of wetlands (0.03 x 3) were required by the project. Accounting for Condition 33, this mitigation obligation results in an additional

0.17 ac wetland creation obligation (0.09 + (0.09 × 0.9)). The project exceeded its RWQCB expanded wetland acreage expansion requirement (after accounting for Condition 33) by approximately 0.53 ac (8.13 ac-7.6 ac)— which is more than the 0.17 ac of additional wetland creation obligation. Because the RWQCB permit specifies that additional acres of expanded or enhanced wetlands may be used to provide for any additional mitigation required by Condition 33, we interpret the mitigation acreage for these unanticipated enhanced wetland impacts to be met (H. T. Harvey 2025).

1.7 2024 Existing Conditions

In 2024, H. T. Harvey prepared an Existing Conditions Report for the project which compared the condition in the expanded and enhanced wetlands to the habitat success criteria in the project’s MMP for absolute cover of native hydrophytic plants, invasive plant cover, plant health and vigor, plant species richness, and hydric soils (H. T. Harvey 2024a). The Existing Conditions Report monitored conditions in the 6 distinct wetland groups created by the project (Figure 2). The percent cover of plant species by wetland group in the 2024 Existing Conditions Report is provided in Appendix A. Photo documentation of site conditions in 2024 from the photo point locations in Figure 2 are provided in Appendix B.

All 6 of the expanded wetland groups met the criteria for plant health and vigor and species richness. None of the expanded wetland areas met the criteria for absolute cover of native hydrophytic plant cover mostly because locally naturalized, non-native and invasive wetland plants constituted a large portion of the vegetation in the

Project Remedial Wetland Mitigation Plan 8 H. T. Harvey & Associates wetland groups (Appendix A). Three expanded wetland groups did not meet the criteria for absolute cover of invasive species and one wetland group (group 6) did not meet the criteria for hydric soils (Table 3), though H.

T. Harvey’s subsequent delineation in 2025 determined that most (but not all) of expanded wetland group 6 is jurisdictional. The enhanced wetland areas did not meet the criteria for species richness, absolute cover of invasive species, or absolute cover of native hydrophytic plants.

Table 3. Summary of Mitigation and Monitoring Plan Performance Criteria Met by Wetland Group in 2024

Year 5 Performance Criteria

Wetland Group

Approximate Surface Area

(Acre)1

Absolute Cover of Native Hydrophytic Plants

Absolute Cover of Invasive Species

Health and Vigor

Species Richness

Hydric Soils

Year 5 Performance Criteria

>70% Native Hydrophytic Plant cover

<15% Invasive Plant Cover

>90% in Good or Fair Condition

At Least 5 Native Wetland Plant Species

Presence of Hydric Soils

Expanded Wetland Group 1

2.61 No Yes Yes NA2 Yes

Expanded Wetland Group 2

2.80 No No Yes NA Yes

Expanded Wetland Group 3

0.25 No No Yes NA Yes

Expanded Wetland Group 4

1.66 No Yes Yes NA Yes

Expanded Wetland Group 5

0.30 No No Yes NA Yes

Expanded Wetland Group 6

0.41 No Yes Yes NA No

All Expanded Wetland Groups

8.03 No No Yes Yes No

All Enhanced Wetlands

0.42 No No Yes No Yes

1 The surface area of wetlands is based on acreages in the project's Mitigation and Monitoring Plan (ICF International 2016) because the 2024 Existing Conditions Report (H. T. Harvey 2024a) was prepared prior to H. T. Harvey's 2025 wetland delineation report.

2 NA because the criteria is assessed among the expanded wetlands, not by group.

1.8 Overview of Recommended Remedial Wetland Mitigation

The mitigation wetlands are adequately sized to meet the project’s mitigation requirements. In 2024, average native wetland vegetation cover in the mitigation wetlands was 47.8% (across all expanded wetland groups and the enhanced wetlands) compared to the final success criteria of 70% native wetland vegetation. Therefore, native wetland cover needs to increase by at least 22.2% to meet the success criteria. We recommend a

Project Remedial Wetland Mitigation Plan 9 H. T. Harvey & Associates combination of invasive plant removal, non-native plant control, and native plantings to shift plant community dominance in the expanded wetland groups and enhanced wetlands to meet the success criteria in the MMP.

In addition, we recommend restoring wetlands impacted by informal trails and modifying drains in wetlands to increase hydroperiod to favor native hydrophytic vegetation. Guidance to implement these actions are provided in Section 2.

Project Remedial Wetland Mitigation Plan 10 H. T. Harvey & Associates

Section 2. Remedial Actions

2.1 Overview

The 2024 Existing Conditions Report recommended remedial actions to set the 8.48 ac wetland mitigations area on a trajectory to meet the success criteria in the MMP (H. T. Harvey 2024a). The actions in the sections below align with the guidance in that report, with modifications based on site conditions observed during the wetland delineation in 2025 and based on completion of fencing to prevent access to wetlands performed in 2025 by the City. The recommended remedial actions are as follows:

• trail decommissioning through wetlands,

• removal of invasive plant species,

• hydrologic modifications (minor reversible modifications to drains present in some wetlands),

• revegetation to increase wetland species richness and native wetland cover, The purpose of these activities is to increase the cover and diversity of native hydrophytic species. This will be accomplished through removal of non-natives followed by planting or, in the case of drain modifications, by modifying abiotic conditions (duration of ponding) in favor of native hydrophytic plants. In addition, the City requests that the RWQCB approve minor modifications to the final success criteria to count non-native, non-invasive, naturalized plants towards the native cover criteria (see Section 3).

2.2 Construction Schedule and Quality Control

The restoration work will be performed by a qualified restoration contractor with field guidance from a qualified restoration ecologist.

The City will implement all of the remedial actions in 2025 with the exception of native plant installation which will be phased. Native plant installation will be implemented both in 2025 and 2026. This phasing will allow the City to contract grow plants in sufficient quantities during the spring/summer of 2026 to complete plant installation and will allow the project to hone preferred planting locations and species based on results of planting in 2025. Invasive plant removal/native plantings may also be needed in future years (e.g., in 2028 and 2029), depending on efficacy observed during 2026 and 2027 monitoring. The project’s MMP allows for as-needed weed control and plant replacement during the project’s 5-year monitoring period (ICF International 2016).

2.3 Trail Decommissioning through Wetlands

Informal trails are present through Wetland Group 1 (2 trails), 2 (2 trails), 4 (1 trail) and 5 (1 trail) resulting in bare ground. The locations of these trails are shown on Figure 3 and total 0.16 ac. The elevation of some trails

Project Remedial Wetland Mitigation Plan 11 H. T. Harvey & Associates appears to be slightly above the elevation of the surrounding wetland. Because of the absence of the vegetation and this subtle difference in elevation in some trail locations, the trails were not mapped as jurisdictional wetlands in the 2025 wetland delineation (Figure 3). In 2025, the City installed fencing to prevent access to all trails except for the trail passing through Wetland Group 5, which is still being designed by the City. We understand that access deterrents for all trails will be completed in 2025. Following completion of access deterrents, we recommend the City implement the following within the former path areas to restore these areas to wetland. This is expected to increase the area of jurisdictional wetlands created by the project relative to the 2025 wetland delineation by approximately 0.16 ac.

• Perform work in the late summer or fall of 2025 prior to onset of winter rains.

• Remove fill soils from paths so that the elevation is equivalent to the surrounding wetland using hand tools (e.g., shovel, wheelbarrow). Dispose of excess fill outside of wetlands.

• Decompact the upper 6 inches of soil using hand tools (e.g., a shovel or rototiller).

• Broadcast seed the with species Table 4, raking seed into the upper ¼ inch of soil surface. Lightly cover the seeded soil surface with weed free rice straw (50% cover) so that bare ground (50% cover) remains visible after straw application. This will help retain soil moisture and encourage seed germination without preventing light penetration to seedlings.

Table 4. Seed Mix for Restoration of Trails through Wetlands

Botanical Name Common Name Broadcast Application Rate (Pounds of Pure

Live Seed per Acre)

Bolboschoenus maritimus Alkali bulrush 8.0

Carex praegracilis Field sedge 3.0

Frankenia salina Alkali heath 1.0

Hordeum branchyantherum Meadow barley 8.0

Limonium californicum Marsh rosemary 0.5

Salicornia pacifica Perennial pickleweed 1.0

Note: Species seeded may be modified based on seed availability.

2.4 Removal of Invasive Plant Species

The following invasive plant removal will be performed. H. T. Harvey mapped locations of invasive plant patches in 2024 (Figure 3). However, a restoration ecologist will flag these areas for removal in the field as well as identify any new areas of invasive plant species to control in 2025. The invasive plant removal areas will be seeded with native wetland species after removal is completed.

ð ð ð ð ð ð

Wetland Group 1

Wetland Group 4

Wetland Group 5

Wetland Group 6

Wetland Group 3

Wetland Group 2

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Feet± Figure 3. Remedial Wetland Mitigation Actions

Palo Alto Municipal Golf Course Reconfiguration Project Remedial Wetland Mitigation Plan (4821-02) September 2025

Mitigation Wetlands (8.48 ac)

Brackish Marsh (0.13 ac)

Non-Tidal Salt Marsh (5.83 ac)

Seasonal Wetland (2.53 ac)

Enhanced Wetlands (0.35 ac) ð Drains

Unofficial Trail (0.16 ac)

Invasive Plants

Perennial Pepperweed (Lepidium latifolium)

Alkali Russian Thistle (Salsola soda)

Iceplant (Carpobrotus edulis) (0.01 ac)

Paspalum TE (Paspalum vaginatum) (0.02 ac)

Greater periwinkle (Vinca major) ( 0.01 ac)<

Iceplant

Paspalum TE

Common Reed

Perennial Pepperweed

Alkali Russian Thistle

Perennial Pepperweed

Greater periwinkle

Project Remedial Wetland Mitigation Plan 13 H. T. Harvey & Associates

2.4.1 Ice Plant

• 0.01 ac of ice plant (Carpobrotus edulis), a highly invasive plant species was present in Wetland Group 1 in 2024. This patch will be removed by pulling and off hauling all above ground ice plant vegetation and hand-pulling root material. Dispose of all plant fragments offsite, as ice plant can readily resprout from root or above ground plant fragments. Rake up and removal all remaining ice plant duff to expose bare ground. Broadcast seed with the seasonal wetland seed mix in Table 5.

Table 5. Seed Mix for Alkali Seasonal Wetlands

Botanical Name Common Name Broadcast Application Rate (Pounds of Pure

Live Seed per Acre)

Baccharis glutinosa Marsh baccharis 0.5

Centromadia pungens subsp.

pungens

Common spikeweed

1.0

Elymus triticoides Creeping wildrye 8.0

Frankenia salina Alkali heath 1.0

Grindelia stricta Marsh gumplant 2.0

Hordeum branchyantherum Meadow barley 8.0

Hordeum depressum Alkali barley 9.0

Juncus patens Common rush 3.0

Salicornia pacifica Perennial pickleweed

1.0

Note: Species seeded may be modified based on seed availability.

2.4.2 Paspalum Turf Ecosystems (TE)

• 0.02 ac of Paspalum TE (Paspalum) was present in 2024 in a single patch. The MMP calls for Paspalum removal in wetlands. All above ground vegetation and as much root material as possible will be removed by hand in 2025. In 2026, any areas of resprout will be treated by wick application of an aquatic herbicide as recommended by a state certified pest control advisor. Removal by hand in 2025 is expected to reduce the amount of vegetation that needs to be treated with herbicide in 2026. Areas of bare ground will be seeded with the mix in Table 4.

2.4.3 Greater Periwinkle

• <0.01 ac of greater periwinkle (Vinca major) was present in 2024 shown in Figure 3. Greater periwinkle is rated as “moderately invasive” by the California Invasive Plant Council (Cal-IPC). Greater periwinkle roots and vegetative material will be removed by hand-pulling. Any bare ground will then be seeded using the seed mix in Table 5.

Project Remedial Wetland Mitigation Plan 14 H. T. Harvey & Associates

2.4.4 Russian Thistle

Russian thistle (Salsola soda) was present in wetland groups 1-5 with an average cover of 2.5%. Russian thistle will be hand-pulled and removed in mid-summer prior to seed set. Any bare areas will then be seeded with the seed mix in Table 4.

2.4.5 Perennial Pepperweed

Perennial pepperweed (Lepidium latifolium) was present in the mitigation wetlands in 2024 (Appendix A). Seed bearing heads will be cut and removed in 2025 to prevent spread. Patches and individual perennial pepperweed plants will be treated with an herbicide approved for aquatic use annually in the spring prior to development of seedheads. Herbicide type and application will be guided by a certified pest control advisor’s recommendation.

2.4.6 Seeding Plan

The seed application rate will be provided by the native seed supplier. Species substitutions may be made to achieve the target native wetland habitat based on seed supply availability. Apply native wetland seed between September 15 and October 15. Rake seed into the upper ¼ inch of soil surface. Lightly cover the seeded soil surface with weed free rice straw (50% cover) so that bare ground (50% cover) remains visible after straw application. This will help retain soil moisture and encourage seed germination without preventing light penetration to seedlings.

2.5 Hydrologic Modifications

Wetland Groups 1, 2, and 6 contain drain structures in their low points which could be modified to alter the wetland hydroperiod. The following provides the rationale for drain modifications in some of these wetlands to help achieve wetland success criteria.

2.5.1 Wetland Group 1

This wetland area has a drain that could be modified. However, the drain is in an area that ponds readily and supports mudflat in the ponded areas, suggesting that increasing the hydroperiod at the lower end of the elevation range in the pond could cause loss of existing wetland vegetation. Therefore, the drain in Wetland Group 1 will not be modified.

2.5.2 Wetland Group 2

This wetland area did not meet the invasive species criteria. The primary invasive species (per the MMP’s definition) were foxtail barley (Hordeum murinum), seaside barley, and Italian wildrye. These species are typical of drier, less inundated wetlands and uplands. Therefore, the depth and duration of ponding will be increased by modifying the elevation of the drain inlet in Wetland Group 2. The drain inlet will be modified such that the inlet elevation is adjustable in small increments (e.g., via installation of 0.2 foot vertical flashboards) so that the system can be modified to incrementally increase or maintain current ponding. This modification is likely to

Project Remedial Wetland Mitigation Plan 15 H. T. Harvey & Associates increase native wetland vegetation cover in the marsh areas, but is unlikely to affect cover in the seasonal wetlands; therefore, this wetland group will also be planted with additional wetland vegetation as described in Section 2.5.

2.5.3 Wetland Group 6

This wetland area did not meet the hydric soil criteria in 2024, but the 2025 delineation determined much of this area is a wetland. The group also didn’t meet the native wetland cover criteria. Therefore, the drain inlet will be modified to increase the depth and duration of ponding per the modification described for Wetland Group 2. This will increase ponding depth and duration, which will likely further shift plant community composition to be dominated by native wetland plant species.

2.6 Revegetation to Increase Species Richness and Native Cover

2.6.1 Overview

In 2024, average native wetland vegetation cover in the mitigation wetlands was 47.8% (across all expanded wetland groups and the enhanced wetlands) compared to the final success criteria of 70% native wetland vegetation. The seasonal wetlands onsite have the lowest native wetland vegetation cover and will therefore be the focus of revegetation efforts. Mitigation wetlands mapped in 2025 as non-tidal salt marsh (5.83 ac; Figure

3) had relatively high native wetland cover, typified by perennial pickleweed. Brackish marsh (0.13 ac) also had relatively high native wetland cover, typified by cattails (Typha latifolia) and field sedge (Carex praegracilis).

Seasonal wetlands (2.53 ac) were dominated by non-native and invasive grasses. This is because the seasonal wetlands are generally located on the slopes between deeper wetland depressions and uplands and the soil is drier and probably less saline than the lower elevation marsh areas, making abiotic conditions favorable for more plant species. Seasonal wetlands did contain native plants such as creeping wild rye (Elymus triticoides; 1.7% cover) and salt grass (Distichlis spicata, 9% cover), but non-native and invasive vegetation were in high abundance such as invasive seaside barley (Hordium marinum; 5.9% cover), invasive Italian rye (Festuca perennis; 2.5% cover), invasive alkali Russian thistle (Salsola soda; 2.2% cover), non-native sickle grass (Parapholis incurva; 10.5% cover), and non-native Rabbits foot grass (Polypogon monspeliensis; 6.0% cover).

To increase the cover of native wetland plants, continuous patches of non-native and invasive dominated seasonal wetland areas will be revegetated with native plant species. The specific patches of non-native and invasive vegetation to be revegetated will be selected and flagged by a qualified restoration ecologist. These areas will be in both the expanded and enhanced wetlands; 0.3 acres will be revegetated in 2025, and an additional 0.3 acres will revegetated in 2026 (Table 6). Soil salinity will be measured in planting areas prior to plant installation to inform species selection.

Project Remedial Wetland Mitigation Plan 16 H. T. Harvey & Associates

Table 6. Seasonal Wetland Revegetation in Wetland Groups to Increase Species Richness and Cover

Year Surface Area (acres)

Revegetation Method

2025 0.3 Seeding (0.2 acre) and container plants installation (0.1 acre)

2026 0.3 Either seed, planting or a combination of both depending on results from 2025

In 2025, non-native/invasive plants will be replaced with native vegetation using two methods: (1) seeding and

(2) container plant installation (Table 6). In both cases, non-native/invasive plants will be trimmed prior to planting. Areas to be seeded will be tilled, then seeded, then straw mulch applied. Areas planted with container plants will not be tilled but will receive a 6-inch-deep layer of straw mulch between plantings to inhibit non-native plant growth. Container plants will receive supplemental irrigation. Both seeded and container plant installation areas will be weeded during the subsequent growing season to encourage establishment of a native plant community. In the spring of 2026, the effectiveness of the revegetation techniques (seeding versus container plant installation) will be observed by a restoration ecologist. In 2026, at least 0.3 acres of non-native/invasive plants will be replaced with native vegetation using the most effective method (seeding or container plant installation; Table 6).

2.6.2 Seeding Plan

In flagged areas, manually remove broadleaf weed and string trim non-native grasses. Scarify or till soil to a depth of 2 inches in preparation for seeding. Broadcast and rake in seed from Table 4 to a depth of 0.25 inches.

Cover the area with weed free rice straw mulch (~70% soil coverage with straw). Water down the straw to prevent displacement by wind.

2.6.3 Container Plant Installation Plan

In flagged areas, string trim existing vegetation to near the soil surface. Add a 6-inch-deep layer of weed free rice straw to suppress weed growth. Between November 15–December 15, plant appropriate native plant species on 3-foot centers into the mulched areas. In 2025, approximately 470 plants will be installed over 0.1 acres. Target plant species are shown in Table 7. The species planting layout in each planting area will be field fit by a restoration ecologist based on soil salinity and moisture. Irrigate plantings immediately after installation and weekly, if needed, until onset of winter rains.

Table 7. Container Plant Installation Palette

Botanical Name Common Name Salt

Tolerance Wetland Indicator

Status1 On-Center

Spacing

Ambrosia psilostachya Western ragweed Low FAC 3

Baccharis glutinosa Marsh baccharis Moderate FACW 3

Carex praegracilis Clustered field sedge Moderate FACW 3

Project Remedial Wetland Mitigation Plan 17 H. T. Harvey & Associates

Deschampsia cespitosa Tufted hair grass Low FACW 3

Distichlis spicata Salt grass High FAC 3

Elymus triticoides Creeping wildrye Low FAC 3

Frankenia salina Alkali heath High FACW 3

Grindelia stricta Marsh gumplant High FACW 3

Juncus balticus Baltic rush Moderate FACW 3

Juncus lescurii San Franscisco rush Moderate FACW 3

Salicornia pacifica Perennial pickleweed High OBL 3 1 Wetland Indicator Status Definitions: FAC= Facultative plant; FACW= Facultative wetland plant; OBL= Obligate wetland plant

2.6.4 Maintenance Plan

Hand remove or string trim non-native plants in both the seeded and planted areas during 3 weeding events in approximately February, April and June in the growing season following plant installation. Provide supplemental irrigation during the dry season to container plants on an as-needed basis to prevent drought stress in the growing season following plant installation.

Continue to provide invasive plant control and planting on an as-needed basis as described in the project’s MMP during the 5-year monitoring period.

Project Remedial Wetland Mitigation Plan 18 H. T. Harvey & Associates

Section 3. Modification to Success Criteria

Naturalized, non-native, non-invasive plant species are common in marshes and seasonal wetlands throughout California. The effort to control these species in favor of native plants is unlikely to substantively improve water quality associated with the mitigation wetlands. In addition, the project’s MMP states:

“Overall success of the site may require accepting a mosaic balance of native and non‐native vegetation.”

Therefore, we request that the RWQCB consider approving the following modification to the MMP’s native cover success criterion:

Current MMP Success Criterion ≥ 70% Absolute Cover Native Hydrophytic Vegetation

Proposed Revised Success Criterion ≥ 70% Absolute Cover Native and Naturalized/Non-native Hydrophytic Vegetation

The species at the project site that are naturalized, non-native (and non-invasive) wetland indicator plants are shown in Appendix A. Examples of naturalized, non-native (and non-invasive) wetland indicator plants present at the site in 2024 include: fat-hen (Atriplex prostrata), brass buttons (Cotula coronopifolia), rabbitsfoot grass (Polypogon monspeliensis), bristly oxtongue (Helminthotheca echiodes), and spiny sowthistle (Sonchus asper). Cover of these species totaled 11.2% in 2024.

This proposed modification to success criteria is included in the proposed revised Monitoring and Adaptive Management Plan in Section 4.

Project Remedial Wetland Mitigation Plan 19 H. T. Harvey & Associates

Section 4. Monitoring And Adaptive Management

The purpose of this section is to establish a clear understanding of the monitoring requirements for the mitigation site in Year 1-5 based on the current, existing conditions for review by RWQCB. Site conditions have changed since the MMP was prepared in 2016 and some of the monitoring methods are no longer necessary in H. T. Harvey’s professional judgement to assess whether the mitigation goals are being achieved.

This section is proposed to replace Chapter 5 of the project’s MMP (ICF International 2016). The original text of the MMP is provided for reference along with the proposed changes. The text in “Cabria font” is the original MMP text. Modifications are indicated both by showing crossed out Cabria font, and by adding monitoring text in “Garamond font”.

The proposed revised monitoring and adaptive management text is as follows:

Monitoring and Adaptive Management To ensure the long‐term success of the restoration effort, it will be necessary to monitor the condition of the restoration site and potentially implement adaptive management1 practices as the site develops toward a sustainable equilibrium condition. The following sections provide details on each component of the monitoring and adaptive maintenance program, and describe requirements for documentation and reporting.

Monitoring Protocol and Performance Criteria During the 5 years following planting (or until the time the established success criteria, defined below, are met), monitoring and adaptive management will focus on the physical and biological development of the mitigation wetlands. The two different types of mitigation wetland, expanded and enhanced, will be tracked and analyzed separately. Monitoring will occur in the spring of each calendar year (March through May, dependent on rainfall) so that annual species may be identified.

Table 6 summarizes the performance criteria that will be used to evaluate the survival of wetland vegetation. These plantings will be considered successful if they meet or exceed the criteria. Overall success of the site may require accepting a mosaic balance of native and non‐ native vegetation. Plant communities will be assessed as a whole, regardless of whether they were planted or seeded.

Physical The project’s 2016 MMP indicates that a California Rapid Assessment Method (CRAM) study will be performed to determine if the mitigation wetlands are functioning as physical wetlands. However, a CRAM study would not identify whether the site functions as a wetland. A jurisdictional wetland delineation is necessary to determine if the site functions as a wetland, which was completed for the project in 2024. Additionally, the MMP calls for comparing results in Years 1, 3 and 5 to a pre-project CRAM score. However, the pre-project baseline CRAM assessment was not performed. Moreover, some of the key CRAM metrics from the

Project Remedial Wetland Mitigation Plan 20 H. T. Harvey & Associates depressional wetland module that would be expected to change over time are being captured by the proposed quantitative quadrat vegetation monitoring; these metrics include native and invasive species cover. Therefore, no CRAM study will be performed.

To ensure that the mitigation wetlands are functioning as physical wetlands, the California Rapid Assessment Method (CRAM) will be used to perform a qualitative evaluation of the wetland. In addition, the presence or absence of hydric soil indicators will be assessed annually at several locations. Table 6 lists the physical performance criteria for the Project site. Physical performance criteria will be assessed in years 1, 3, and 5.

1 Table 6. Physical Performance Criteria

P1. CRAM Assessment P2. Hydric Soil Indicators Year 1 Target CRAM score between 90 and 95 Presence of hydric soils Year 3 Target CRAM score between 90 and 95 Presence of hydric soils Year 5 Target CRAM score between 90 and 95 Presence of hydric soils

1 Adaptive management describes a resource management style that embodies change or modification (“adaptation”) in response to the outcome of previous management actions or to advances in scientific understanding. Under adaptive management, management action is initiated, results are monitored, and subsequent management actions are adjusted for better outcome, based on information collected during monitoring or other new data.

Performance Criteria P1: CRAM Assessment The CRAM assessment will follow the protocols found in the latest version of the California Rapid Assessment Method for Wetlands: Depressional Wetlands Field Book (San Francisco Estuary Institute 2013). A pre‐Project CRAM analysis will be performed to evaluate the baseline condition of the wetland habitats within the Project site. The pre‐Project CRAM scores establish the baseline for comparative purposes during the monitoring program.

Representative assessment areas will be established within the expanded and enhanced wetlands to measure the change in ecosystem functions and services over the course of the 5‐ year monitoring program.

Performance Criteria P2: Hydric Soils

The purpose of a hydric soils assessment is to determine if the created mitigation wetlands are establishing wetland conditions. Grading for the wetland mitigation areas was completed in 2016-2017. Hydric soils were assessed during the 2024 existing conditions study (H. T. Harvey & Associates 2024a) and for the wetland delineation completed in 2025 (H. T. Harvey & Associates 2025). Those studies show that hydric soils are present within the 8.48 ac area mapped as jurisdictional wetlands (Figure 2). Presence/absence of hydric soils change slowly over time (e.g., on the order of decades) and are not expected to change over a 5-year monitoring period. Therefore, no further hydric soil monitoring will be performed.

Hydric soil indicators will be evaluated by excavating soil pits in several locations to approximately 20 centimeters in depth and examining the morphological characteristics of the soil profile. In particular, the profile will be examined for the presence of those redoximorphic

Project Remedial Wetland Mitigation Plan 21 H. T. Harvey & Associates features and other indicators that may occur in the soils. Such features generally include low chroma colors, soft masses, and high organic matter content. These features and indicators are described in Field Indicators of Hydric Soils in the United States, Version 7.0, by L. M. Vasilas, G.

W. Hurt, and C. V. Noble (U.S. Department of Agriculture 2010). If the soil profile displays the relevant indicators, the soil is regarded as having met the criteria for a hydric soil. Any excavated soil pits will be immediately backfilled after soil examination and will not be left open overnight.

Biological Successful establishment of wetland vegetation will be based on health and vigor of native, hydrophytic wetland species, absolute percent cover of both native, hydrophytic and invasive species, and native plant species richness (Table 7).

Successful establishment of wetland vegetation will be based on the percent cover of native and naturalized, non-invasive hydrophytic wetland species (see Section 3). Per the MMP, invasive species are non-native species ranked as “high” and “moderate” risk by the Cal-IPC’s Invasive Plant Inventory (Cal-IPC 2006).

Table 7. Performance Criteria for Wetlands B1. Absolute cover

(native/invasive) B2. Health and Vigor B3. Species Richness

Year 1 Target >30% native/naturalized hydrophytic plant cover/<30% invasive plant cover

>50% in Good or Fair condition

At least 2 native wetland plant species

Year 2 Target >40% native/naturalized hydrophytic plant cover/<25% invasive plant cover

>70% in Good or Fair condition

At least 2 native wetland plant species

Year 3 Target >50% native/naturalized hydrophytic plant cover/<25% invasive plant cover

>75% in Good or Fair condition

At least 3 native wetland plant species

Year 4 Target >60% native/naturalized hydrophytic plant cover/<20% invasive plant cover

>80% in Good or Fair condition

At least 4 native wetland plant species

Year 5 Target >70% native/naturalized hydrophytic plant cover/<15% invasive plant cover

>90% in Good or Fair condition

At least 5 native wetland plant species

Hydrophytic Vegetation All native wetland vegetation will be evaluated based on the dominance of species that are hydrophytic, which is defined as species that persist in inundated landscapes. Hydrophytic vegetation is based on the wetland indicator status of a plant species (Lichvar 2013) [or the most recent version of the National Wetland Plant List]. Species listed as facultative occur in

Project Remedial Wetland Mitigation Plan 22 H. T. Harvey & Associates both wetlands and non‐wetlands, and species listed as facultative wetland or obligate are more often found or almost always found (respectively) in wetlands. These species illustrate wetland functionality because the hydroperiod is controlling the plant species assemblage.

Absolute cover of native hydrophytic vegetation will be monitored using the line transect method described below.

Performance Criteria B1. Absolute Cover

The 8.48 ac expanded and enhanced wetland monitoring areas will be divided into the 6 spatially contiguous “wetland groups” shown on Figure 2. Each wetland group is located within the same depression graded between higher elevation golf course greens. The hydrology between wetland groups differs slightly based on differences in grading, depth to groundwater, and immediate watershed size, which influences wetland vegetation composition. To capture this variability, absolute cover of wetland vegetation will be sampled using the quadrat method (Bonham 1989) collected from stratified random locations within the expanded and enhanced wetlands in each wetland group. Quadrats will also be stratified to represent areas that are seeded/planted (see Section 2.5). The number of quadrats sampled will be proportional to the size of the enhanced and expanded wetland areas and will proportionally represent the contribution of seeded/planted areas to total cover (e.g., after 0.6 acres are revegetated, 0.6/8.48 = 0.071 x 80 quadrats = 6 quadrats will be located in the seeded/planted areas). The final number of samples collected during each annual monitoring event will be based on the variability of wetland vegetation percent cover among the quadrats. The number of quadrats will be the point where additional samples do not substantially change the average wetland vegetation cover among the expanded wetlands and, separately, among the enhanced wetlands following methods in Kershaw 1973. Initially, data from 70 quadrats will be collected across the wetland groups (60 among the expanded wetlands, 10 among the enhanced wetlands), as this proved an adequate sample size in 2024 (H. T.

Harvey & Associates 2024a).

The line transect survey method will be used to determine absolute cover of native, hydrophytic species and invasive species. Absolute cover provided by seeded and naturally recruited wetland plant species for each area will be monitored using randomly selected 1‐square‐meter quadrats placed along permanent 100‐meter‐long transects. If wetland dimensions do not accommodate a 100‐meter transect, the transect length and/or quantity will be shortened to the dimensions of the wetland. Figure 7 illustrates a trend line based on plot samples from a hypothetical data collection. Transect monitoring will identify the dominant species and note any changes in the dominant species over the length of each transect. Although transect monitoring will be conducted and tracked in each wetland, Performance Criteria B1 will have been met if the mean absolute cover per square meter in the expanded wetlands and the mean absolute cover per square meter in enhanced wetlands meets or exceeds that year’s target.

Absolute cover of all plant species, including invasives, will be determined by sampling randomly placed 1‐square‐meter plots along the transects established through each rehabilitation area.

Plot sampling will be conducted using a stratified random design. Transects will be stratified by dividing them into 10 equal‐sized subtransects.