Attachment1_MOTCO As-built report.111423.pdf

WRA, Inc. | 2169 G East Francisco Blvd., San Rafael, CA 94901 www.wra-ca.com · ph: 415.454.8868

November 17, 2023

San Francisco Bay Regional Water Quality Control Board 1515 Clay Street, Suite 1400 Oakland, CA 94612 Attn: Katie Hart Place ID 884640

WDID# 2 CW450388

San Francisco District, U.S. Army Corps of Engineers 450 Golden Gate Avenue San Francisco, CA 94102 Attn. Greg Brown Corps File No. SPN-2021-00214

Re: As-built Report for the Military Ocean Terminal Concord Marsh Restoration Project

This letter was prepared on behalf of the U.S. Department of Transportation, Federal Aviation Administration (USDOT; Applicant) to document the completed status of the Military Ocean Terminal Concord Marsh Restoration Project (Project) on the Concord Naval Weapons Station (CNWS) in Concord, California. This letter report serves as the “as-built report” described in the Habitat Restoration section of the Updated Regulatory Permit Application (Updated Application) prepared by WRA, Inc. (WRA) in November 2022. The report herein includes a description of the as-built conditions, including seed mixes used in the wetland areas, and any deviation from the approved plans.

1.0 BACKGROUND

The Project Area is located in northern Contra Costa County within the federally controlled CNWS lands (Figures 1 and 2, Attachment A). The center of the site previously supported two Federal Aviation Administration (FAA) antennae structures and a small electrical housing unit. Prior to Project implementation, the Project Area included a 150-foot by 150-foot fenced enclosure surrounding the FAA infrastructure, and an approximately 320-foot gravel road used to access the site. The Project Area is surrounded by a mosaic of fresh and saline emergent wetland, tidal marsh, and coastal scrub. The adjacent Hastings Slough East marsh receives tidal flow and is dominated by saltgrass (Distichlis spicata), pickleweed (Salicornia pacifica), rushes (Juncus spp.), and spearscale (Atriplex prostrata).

The purpose of the Project was to decommission and remove the existing FAA infrastructure and restore the Project Area to near pre-existing conditions. Project components included the demolition and removal of existing infrastructure and fencing, removal of surface gravel from the access road, and redistribution of surface soils to restore original marsh grades and fill in holes http://www.wra-ca.com/ left by the removal of structures. Once these activities were completed, disturbed areas were seeded to promote wetland re-establishment. This as-built report describes conditions immediately following infrastructure removal and seeding and fulfils reporting requirements for Year 0.

The Project Area will be monitored for a period of five years, as described in the Updated Application and required by Condition 3 of the approved Regional Water Quality Control Board (RWQCB) Water Quality Certification (WQC).

1.1 Construction Phase

On September 6, 2023, the Project commenced with the clearing of all vegetation within the work areas to eliminate cover for the salt marsh harvest mouse (SMHM; Reithrodontomys raviventris). Vegetation clearing was completed using only hand tools (e.g., string trimmers), and occurred as a two phased method when vegetation was taller than 12 inches. Prior to any vegetation removal, a qualified biological monitor disturbed the vegetation using a rake to allow any SMHM to passively leave the area and move into adjacent marsh habitat (i.e., flush).

Following vegetation removal, SMHM exclusion fencing was installed under the guidance of qualified biological monitors, including SMHM expert Katie Smith, Ph.D. The Project’s Biological Opinion (File No. 2022-0014966-S7-001) states that exclusion fencing should be buried to a depth of 4 inches and be adjoined by a 10-foot buffer. However, due to issues regarding uneven terrain and dense vegetation, it was determined that installing the fence as described would reduce its efficacy (e.g., uneven terrain leads to fence integrity issues) and result in unnecessary impacts to marsh habitat. Consequently, Dr. Katie Smith determined that stapling an apron style ERTEC fence would be more effective at this location, as illustrated in Attachment B, and she confirmed that a 3-to-5-foot cleared vegetation buffer would be sufficient to ensure that no mice would enter the work area. Additionally, the exclusion fence was relocated from outside of the original chain-link footprint to just inside of the chain-link footprint, where the ground was more open and level. These modifications were verbally approved in conversations between Dr.

Katie Smith and Brian Hansen with the United States Fish and Wildlife Service (USFWS).

Once the exclusion fence was installed, a construction crew used heavy equipment (e.g., excavator, loader) to demolish the existing infrastructure, including chain link fencing and associated footings. The chain link fence was removed using an excavator from inside the exclusion fence. Old fence posts were pulled straight up out of the ground and fence holes were filled in immediately by hand. Exposed gravel from within the enclosure and along the access road was also removed and disturbed areas were backfilled with clean fill, as necessary. All infrastructure materials removed from the site were hauled offsite for disposal.

1.2 Revegetation

Once all structures, fencing, and gravel were removed from the site, the disturbed areas were seeded using a native seed mix to promote the re-establishment of salt marsh vegetation within the restored areas. In addition, emergent marsh vegetation is also expected to naturally revegetate from the remaining root stock (i.e., vegetation within the Project Area was trimmed but not fully removed so that it may regrow the next season). Furthermore, the access road was abandoned in place to allow for the continued colonization by marsh vegetation.

During the initial seeding, the quantity of seed mix needed was under-calculated, resulting in an insufficient distribution of only 6 lbs. of seed. To ensure that the total seed amount met the minimum rate requirement, WRA biologists re-visited the site on October 25, 2023, to distribute an additional 35 lbs. of seed. Therefore, the seed mix distributed throughout the disturbed/restored areas amounted to a rate of 50 pounds per acre, in accordance with the Updated Application. During the site visit on October 25, WRA biologists also observed a significant amount of new vegetation growth, primarily consisting of small pickleweed plants that had re-colonized disturbed areas since the completion of the Project.

Seeds were distributed using a broadcast seeding method and were then hand-raked throughout the Project Area. The Project used a California native wetland seed mix based on the native species that currently occur in the Project Area, consistent with the seed mix proposed in the Updated Application. Table 1 depicts the species composition of the wetland native seed mixed used.

Table 1. Wetland Native Hydroseed Mix

SCIENTIFIC NAME COMMON NAME

Salicornia pacifica; OBL Pacific pickleweed

Frankenia salina; FACW Alkali heath

Distichlis spicata; FAC Salt grass

Bolboschoenus maritimus; OBL Salt-marsh bulrush

1.3 Photo Documentation

As described in Condition 3 of the approved WQC, 8 photo-documentation points were established prior to the start of Project activities (Attachment B). Photos were taken at the photo points prior to the initiation of vegetation removal on September 6, 2023, and immediately following Project completion on September 13, 2023, after exclusion fencing was removed and seeding was completed. Pre-construction and post-construction photographs at these locations are shown in Attachment C. Additional photographs taken during the additional site visit conducted by WRA on October 25, 2023 are also included in Attachment C.

1.4 Monitoring Requirements and Success Criteria

Restoration activities were implemented per the permit requirements, and it is anticipated that the disturbed wetland areas will restore to pre-existing conditions, or better, as a result of the Project. The site will be monitored every year for a period of no less than 5 years, as described in the Updated Application, and as required per the permits. Each year, beginning in 2024 (Year 1), a comprehensive annual report documenting the monitoring results will be prepared. This monitoring will include the following:

• Quantitative measures of vegetative cover, density, and species-richness of the restored site and comparison to similar parameters within non-manipulated areas in the adjacent marsh (reference areas).

• Monitoring the absolute cover of wetland species (Target percent cover of wetland plants should be ≥ 75 percent of the reference site at the end of Year 5).

• Monitoring the relative cover of native species (Target percent cover of native plants should be ≥ 75 percent of the reference site at the end of Year 5).

• Monitoring the general conditions of the restoration site

• Monitoring the presence of invasive plants on the California Invasive Plant Council (Cal-

IPC) list with a “high” or “moderate” rating (Target percent cover of High or Moderate invasives should not exceed 10 percent).

• Photographs of the site from the established photo monitoring locations.

If you have questions on any aspect of this as-built letter for the Military Ocean Terminal Concord Marsh Restoration Project, please contact Hope Kingma at (510) 882-5137.

Sincerely, Hope Kingma Biology and Regulatory Permitting Director Hope.kingma@wra-ca.com

Cc: Evan Starr

USDOT

Evan.starr@dot.gov

Enclosures:

Attachment A: Project Location and Overview Figures Attachment B: Schematic Diagram for Apron Style Exclusion Fence Attachment C: Photo Monitoring Point Location Map Attachment D: Site Photographs

Attachment A

ATTACHMENT A.

Project Location and Overview Figures

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Sources: National Geographic, WRA | Prepared By: mrochelle, 2/18/2021

Study Area

View Extent

FAA Concord (CCR) Outer Marker (OM) Facility MotCo, Concord, California 0 21

Miles

Figure 1. Study Area Regional Location Map

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Sources: 2018 Google Earth Aerial, WRA | Prepared By: mrochelle, 3/30/2021

FAA Concord (CCR) Outer Marker (OM) Facility MotCo, Concord, California

Figure 2.

Aerial Map of Site

0 200100 Feet

Study Area - 0.59 ac.

Kinney Blvd

Attachment B

ATTACHMENT B.

Schematic Diagram for Apron Style Exclusion Fence

E-Fence™ (Patent #US8402630, others pending)

E-Fence™ Installation Details © 2008-15 ERTEC Environmental Systems

Jan 2015 NOT TO SCALE www.ertecsystems.com 510-521-0724

E-Fence DETAILS – Wildlife Exclusion - no trench – apron

42” – height above og

Construction

Side

E-Fence 48”

T-Post 5.0, 5.5 or

6.0’ 0.95 lbs/ft

14 gauge guidewire (typ)

Sink T-Posts 18” below original grade original grade

(og)

6” +/- 1”

E-Fence Apron 15” og

Key:

E-Fence tie:

Wire or plastic tie

At section overlap Use wire or plastic ties.

Close all gaps.

Use 6x1x6” 9 gauge

Sod Staples or 6” Nails

(60D Bright Common)

3 pins every 2 or 3 LF

Apron http://www.ertecsystems.com/

Attachment C

ATTACHMENT C.

Photo Monitoring Point Location Map

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Sources: 2018 Google Earth Aerial, 2018 Norcal Fire LiDAR, WRA | Prepared By: rochelle, 9/26/2023

Figure 3. Photo Monitoring Locations

Military Ocean Terminal Concord Marsh Restoration Project MotCo, Concord, California

Project Area - 0.59 ac.

Photo Monitoring Locations

Attachment D

ATTACHMENT D.

Site Photographs

Photo Point 1: Pre-construction. Photo taken on September 6, 2023.

Photo Point 1: Post-construction (Year 0). Photo taken immediately following construction on September 13, 2023.

Attachment D. Site Photographs 1

Photo Point 1: Retaken during additional seed distribution on October 24, 2023, to illustrate current site conditions and new plant growth.

Attachment D. Site Photographs 2

Photo Point 2: Pre-construction. Photo taken on September 6, 2023.

Photo Point 2: Post-construction (Year 0). Photo taken on September 13, 2023.

Attachment D. Site Photographs 3

Photo Point 3: Pre-construction. Photo taken on September 6, 2023.

Photo Point 3: Post-construction (Year 0). Photo taken on September 13, 2023.

Attachment D. Site Photographs 4

Photo Point 4: Pre-construction. Photo taken on September 6, 2023.

Photo Point 4: Post-construction (Year 0). Photo taken on September 13, 2023.

Attachment D. Site Photographs 5

Photo Point 5: Pre-construction. Photo taken on September 6, 2023.

Photo Point 5: Post-construction (Year 0). Photo taken on September 13, 2023.

Attachment D. Site Photographs 6

Photo Point 6: Pre-construction. Photo taken on September 6, 2023.

Photo Point 6: Post-construction (Year 0). Photo taken on September 13, 2023.

Attachment D. Site Photographs 7

Photo Point 7: Pre-construction. Photo taken on September 6, 2023.

Photo Point 7: Post-construction (Year 0). Photo taken on September 13, 2023.

Attachment D. Site Photographs 8

Photo Point 8: Pre-construction. Photo taken on September 6, 2023.

Photo Point 8: Post-construction (Year 0). Photo taken on September 13, 2023.

Attachment D. Site Photographs 9

Vegetation conditions within the Project site during seed distribution by WRA. Photo taken on October 24, 2023; from the access road, facing south.

Vegetation conditions within the Project site during seed distribution by WRA. Photo taken on October 24, 2023; facing western corner.

Attachment D. Site Photographs 10

New phragmite growth observed where vegetation was removed for exclusion fence installation. Photo taken during additional seed distribution by WRA on October 24, 2023.

New pickleweed growth observed within the Project site during seed distribution by WRA.

Photo taken on October 24, 2023.

Attachment D. Site Photographs 11