High Tide Refuge Islands for the San Project Project # 3415-04€¦ · canopy architecture to provide high and moderate (respectively) forcover rails. Replanting of gumplant will

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High Tide Refuge Islands for the San Francisco Estuary Invasive Spartina Project

Year-2 Monitoring Report

Project # 3415-04

Prepared by

H. T. Harvey & Associates

Prepared for

California Coastal Conservancy1330 Broadway, Suite 1300

Oakland, CA 94612Attn: Marilyn Latta, Project Manager

16 April 2015

Executive Summary

Overview The California Coastal Conservancy’s Invasive Spartina Project (Project) constructed 22 high tide refuge islands (refuge islands) between 2012 and 2014 to reduce mortality of California Ridgeway’s rail (Rallus obsoletus obsoletus, formerly the California clapper rail [Rallus longirostris obsoletus]) during extreme high tides. Project permits issued by the U.S. Fish and Wildlife Service (USFWS) and the Bay Conservation and Development Commission (BCDC) require the Conservancy monitor the 22 refuge islands annually for 3 and 5 years (respectively) to assess whether islands function as intended. Currently, annual refuge island monitoring comprises annual vegetation and topography monitoring to evaluate establishment of gumplant (Grindelia stricta) dominated high tide refuge habitat on islands. The first 6 refuge islands were built in December-January of 2012-2013. H. T. Harvey & Associates monitored the vegetation and habitat elevation of the first 6 islands in May 2013, 5 months after construction. Following construction of the remaining 16 islands in December-January of 2013-2014, H. T. Harvey & Associates monitored the vegetation and habitat elevation of all 22 refuge islands in September-October 2014 (Table Ex1). This report documents the monitoring carried out in September- October 2014. Table Ex1: Construction and Monitoring Schedule Overview

Phase Construction Date # of Islands Constructed

Monitoring Date # of Islands Monitored

Year 1 (pilot) Refuge Islands December-January 2012-2013 6 May 2013 6

Year 2 Refuge Islands December-January 2013-2014 16 September-October 2014

22

Vegetation Gumplant survival on the year 1 refuge islands averaged 27.1% in September-October 2014, a decline from 62.0% average survival in May 2013. By contrast, gumplant survival on the year 2 refuge islands averaged 83.8%, higher average survival than seen on year 1 islands at a similar time stage. The higher gumplant survival on year 2 islands is likely explained by the (1) use of 1-gallon container size for gumplant plantings in year 2 (versus D-40 container size in year 1) and (2) the higher elevation of year 2 islands. Installed marsh sod has led to robust native marsh plant cover on refuge islands. Both year 1 and year 2 refuge islands had 70%-100% native tidal marsh plant cover. Islands were dominated by perennial pickleweed, saltgrass (Distichlis spicata), fleshy jaumea (Jaumea carnosa), alkali heath (Frankenia salina), and gumplant.

High Tide Refuge Islands for the SFEISP Project Year-2 Monitoring Report

i H. T. Harvey & Associates 16 April 2015

Marsh plant cover in year 1 and year 2 excavation areas was 38% and 33%, respectively. Excavation area cover was primarily perennial pickleweed. Cover was higher on excavation area side slopes than the of excavation area bottom.

Earthen Island Function Following construction, year 1 and year 2 refuge islands were expected to settle to approximately +0.5 ft above MHHW and +0.8 ft above MHHW (respectively). With establishment of 2-3-ft tall gumplant, this will provide cover for California Ridgeway’s rail during most high tide events. We found that 4 of the 6 year 1 islands and all year 2 islands remained above +0.5 ft above MHHW. Thirteen of the 16 year 2 islands remained above +0.8 ft above MHHW. Therefore, 20 of the 22 islands were within the targeted design elevation range to provide high tide refuge cover for rails once gumplant establishes. The other 2 islands are a 2-3 inches below the target design elevation. Gumplant was (on average) 1.4 ft tall on year 1 islands and 1.7 ft tall on year 2 islands. Two of the year 1 islands (at Martin Luther King New Marsh (MLK Marsh) and Bair Island have developed sufficient gumplant canopy architecture to provide high and moderate cover (respectively) for rails. Replanting of gumplant will be needed on the remaining 4 year 1 islands to develop good cover. As expected, gumplant plantings on most year 2 islands are recovering from transplant shock and have not yet developed gumplant canopy architecture that would provide cover for rails. Moderate gumplant cover is being provided at the two islands at MLK Marsh where gumplant establishment has occurred more rapidly (likely due to use of terrestrial soil for construction). We anticipate that 1-3 more growing seasons will be needed for gumplant on most islands to mature enough to provide good cover for rails. On nearly all refuge islands, perennial pickleweed dominated vegetation provides cover to a height of approximately 0.5-1 ft above the island ground surface, providing suitable cover for the salt marsh harvest mouse and some cover for rails.

Recommendations Island Design. Based on these findings we provided the following recommendations for island design, planting and maintenance to the Conservancy in November 2014. These recommendations were carried out during construction of the 21 additional refuge islands in the winter of 2014- 2015.

1. Increase constructed earthen island top elevations to 1.5 - 1.7 ft above MHHW. Gumplant percent survival has been generally higher on islands constructed at higher elevations in the tidal frame. Therefore, to sustain gumplant survival as island settle, we recommend increasing the height of islands tops to be slightly below the high tide line.


ii H. T. Harvey & Associates 16 April 2015

2. Experimentally incorporate terrestrial soil in gumplant planting pits. Gumplant canopy

structure has established most rapidly on year 1 and year 2 islands built using terrestrial soil (at MLK Marsh). Therefore, we recommend experimentally installing gumplant in planting pits amended with terrestrial soil on refuge islands otherwise constructed using marsh sediment. This treatment has the potential to speed establishment of dense gumplant canopies on refuge islands.

Future Island Planning, Maintenance, and Monitoring. We have the following island recommendations for future island planning, maintenance and monitoring:

1. Plan and build islands to ensure target elevation. To avoid constructing islands below the design elevation, island locations could be ground-truthed earlier in the site selection/permitting process to avoid construction in areas with relatively unconsolidated sediments. This would require USFWS permission for restoration ecologists to access marshes during Ridgway’s rail breeding season. Alternately, islands built using low bulk density material could be built higher than the design grade to offset anticipated consolidation/settlement.

2. Replant gumplant on selected islands. We recommend the Conservancy replant salt-hardened

gumplant in 1-gallon container plants in locations and approximate quantities listed below in the Table ES-1. Table ES-1. Gumplant Replanting Recommendations

Marsh Year Built Island Number Recommended Gumplant Replanting Quantities

Bair Island Year 1 BAIR1 28

Belmont Slough N Year 1 BELN1 49

Belmont Slough S Year 1 BELS1 46

Bird Island Year 1 BIRD1 53

Cooley Landing Year 1 COOL1 34

Arrowhead Marsh Year 2 ARH1 16


Total 252

3. Incorporate Simple, Rapid Field Measurements of Soil Parameters Into Year-3 Island Monitoring. Conduct rapid field measurements of soil paste salinity and pH on a sub-set of refuge islands compared to adjacent natural stands of gumplant to better understand the effect of island construction on soil parameters most likely to affect gumplant establishment.


iii H. T. Harvey & Associates 16 April 2015

Table of Contents

Section 1.0 Introduction ............................................................................................................................................. 1 1.1 Project Background ................................................................................................................................................ 1 1.2 Refuge Island Construction Date, Location, and Design ................................................................................ 1 1.3 Monitoring Purpose ............................................................................................................................................... 3 1.4 Refuge Island Design Elevation ........................................................................................................................... 3

Section 2.0 Methods .................................................................................................................................................... 5 2.1 Habitat Elevation .................................................................................................................................................... 5

2.1.1 Habitat Elevation Monitoring ....................................................................................................................... 5 2.1.2 Consolidation/settlement .............................................................................................................................. 5

2.2 Vegetation ................................................................................................................................................................ 6 2.2.1 Refuge Islands .................................................................................................................................................. 6 2.2.2 Excavation Areas ............................................................................................................................................. 7

2.3 Gumplant Survival versus Refuge Island Elevation ......................................................................................... 7 2.4 Photo-documentation ............................................................................................................................................ 7

Section 3.0 Results and Discussion ........................................................................................................................... 8 3.1 Habitat Elevation .................................................................................................................................................... 8

3.1.1 Refuge Island Elevations ................................................................................................................................ 8 3.1.2 Excavation Areas ........................................................................................................................................... 10

3.2 Vegetation .............................................................................................................................................................. 11 3.2.1 Gumplant Survival ........................................................................................................................................ 11 3.2.2 Gumplant Height .......................................................................................................................................... 14 3.2.3 Qualitative Percent Cover ............................................................................................................................ 16

3.3 Gumplant Survival versus Island Elevation ..................................................................................................... 18 3.4 Photo-documentation .......................................................................................................................................... 18 3.5 Status of Earthen Island Function ..................................................................................................................... 19

Section 4.0 Design, Maintenance and Monitoring Recommendations ............................................................. 20 4.1 Refuge Island Design ........................................................................................................................................... 20 4.2 Future Planning, Maintenance and Monitoring ............................................................................................... 20

Section 5.0 Literature Cited ...................................................................................................................................... 22 Figures Figure 1. Refuge Island Location Map ............................................................................................................................ 2 Figure 2. Year 1 and Year 2 refuge island average elevations (+/- SE) over time. .................................................. 8 Figure 3. Year 1 and Year 2 excavation area average depth (+/- SE) over time. ................................................... 11 Figure 4. Year 1 Refuge Island Average Gumplant Survival (+- SE) Over Time

By Topographic Position ............................................................................................................................ 12 Figure 5. Year 2 Refuge Island Gumplant Average Survival (+/- SE) Over Time

By Topographic Position ............................................................................................................................ 12 Figure 6. Year 1 Refuge Island Gumplant Average Height (+/- SE) Over Time

by Topographic Position ............................................................................................................................ 14 Figure 7. Year 2 Refuge Island Gumplant Average Height (+/- SE) Over Time

by Topographic Position ............................................................................................................................ 16 Figure 8. Gumplant Survival Versus Elevation (Year 1 islands are shown in green,

year 2 islands are shown in blue) ............................................................................................................... 18


iv H. T. Harvey & Associates 16 April 2015

Tables Table 1. Duration of Vegetation and Topography Monitoring Required

by Project Permits .......................................................................................................................................... 3 Table 2. Photo-documentation Locations ..................................................................................................................... 7 Table 3. Refuge Island and Excavation Area Elevations.............................................................................................. 9 Table 4. Refuge Island Gumplant Survival ................................................................................................................... 13 Table 5. Gumplant Heights ............................................................................................................................................. 15 Table 6. Percent vegetation cover in refuge island excavation and fill areas ........................................................... 17 Table 7. Gumplant Replanting Recommendations ..................................................................................................... 21 Appendices Appendix A. Lessons Learned From Construction of California Clapper

Rail Earthen High Tide Refuge Islands ...................................................................................................... 1 Appendix B. Invasive Spartina Project Pilot Earthen Island

Construction Notes to Contractors ............................................................................................................ 1 Appendix C. Photo-documentation................................................................................................................................ 1 Preparers Ron Duke, M.A., Principal-In-Charge Max Busnardo, M.S., Project Manager, Sr. Restoration Ecologist Gavin Archbald, M.S., Restoration Ecologist Joe Howard, M.L.A., Principal, Landscape Architect


v H. T. Harvey & Associates 16 April 2015

Section 1.0 Introduction

1.1 Project Background

The California Coastal Conservancy’s (Conservancy) Invasive Spartina Project (Project) constructed 22 high tide refuge islands (refuge islands) between 2012 and 2014 (H. T. Harvey & Associates 2014) as one of several habitat enhancement measures required by the U. S. Fish and Wildlife Service (Service) to benefit the endangered California Ridgeway’s rail (Rallus obsoletus obsoletus, formerly the California clapper rail [Rallus longirostris obsoletus], hereafter, “rail”) in marshes where hybrid Spartina (Spartina foliosa x alterniflora) is being eradicated (USFWS 2012a). Refuge islands are designed to mimic the high tide refuge function provided by gumplant (Grindelia stricta) lined tidal marsh slough channels in mature tidal marshes. The primary purpose of the refuge islands is to reduce rail mortality caused by predation during extreme high tides. These islands are expected to provide similar high tide refuge benefits for salt marsh harvest mice (Reithrodontomys raviventris).

1.2 Refuge Island Construction Date, Location, and Design

In December-January of 2012- 2013, the Conservancy constructed 6 refuge islands: at Bair Island (1 island), Belmont Slough North (1 island), Belmont Slough South (1 island), Bird Island (1 island), Cooley Landing (1 island), and MLK/New Marsh (1 island) (H. T. Harvey & Associates 2013a). In prior reports, these refuge islands were referred to as “pilot islands”. Hereafter, the first 6 refuge islands are referred to as “year 1 refuge islands”. In December-January of 2013-2014, the Conservancy constructed the 16 remaining refuge islands required by the Service (hereafter, the “year 2 refuge islands”): at Arrowhead Marsh (2 islands), Bair Island (3 islands), Bunker Marsh (2 islands), Cogswell Marsh (6 islands), Cooley Landing (1 island), and MLK/New Marsh (2 islands) (H. T. Harvey & Associates 2014). Figure 1 shows the high tide refuge island general locations. Year 1 and 2 refuge islands were built to be approximately 25 feet (ft) long by 10 ft wide with island tops approximately 2 ft above the marsh plain and located adjacent to a tidal marsh slough channel (H.T. Harvey & Associates 2013a and 2014). Nineteen of the 22 refuge islands were constructed using marsh mud excavated from along a nearby tidal slough channel (the “excavation area”). Three refuge islands (at MLK/New Marsh) were constructed using terrestrial clay subsoil from a farm in Petaluma, CA (H. T. Harvey & Associates 2013c). All refuge islands were capped with marsh sod (e.g., the upper ~6 inches (in) of marsh vegetation and mud removed from the fill and excavation areas) and then refuge island tops and sides were planted with gumplant (Grindelia stricta) and saltgrass (Distichlis spicata) container plants. Maps of individual refuge islands, design specifications, and construction methods are provided in two Notes to Contractors documents used to guide construction of the year 1 and year 2 refuge islands: respectively, the Invasive Spartina Project Pilot Earthen Island Construction Notes to Contractors and the Invasive Spartina Project Earthen


1 H. T. Harvey & Associates 16 April 2015

Arrowhead Marsh

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Bird Island

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Bunker Marsh

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Figure 1: Refuge Island Location MapHigh Tide Refuge Islands for the San Francisco Estuary

Invasive Spartina Project Year-2 Monitoring Report (3415-04)

High Tide Refuge IslandsYear 1 (6 islands)

Year 2 (16 islands)

April 2015

Island Construction Notes to Contractors documents (Appendix A and Appendix B; H. T. Harvey & Associates 2012 and 2013b). The 22 islands were largely built to the design parameters, as documented in “as-built” memoranda submitted to the Conservancy (H. T. Harvey & Associates 2013a & 2014).

1.3 Monitoring Purpose

Project permits from the Service and the Bay Conservation and Development Commission (BCDC) require annual monitoring of refuge islands for 3 and 5 years, respectively (Table 1). Refuge islands are not required to meet specific success criteria. However, monitoring is designed to address the degree to which the islands provide high tide refuge habitat suitable for use by the rail and salt marsh harvest mouse (BCDC 2012; USFWS 2012b). This report characterizes the ecological condition of the 22 refuge islands in September- October 2014, 9 months after construction of the year 2 islands and 21 months after construction of the year 1 islands. Therefore, this report constitutes the first year of monitoring for the year 2 islands and the second year of monitoring for the year 1 islands. Table 1. Duration of Vegetation and Topography Monitoring Required by Project Permits

Permitting Agency Biological Opinion/Permit Number

Habitat Monitoring Required

U.S. Fish and Wildlife Service 2003-27819S 3 years

Bay Conservation and Development Commission

M2012.016.00 5 years

This report documents changes in the habitat elevation and vegetation of the 22 refuge islands in order to, (1) assess whether the earthen islands are on a trajectory to provide high tide refuge habitat for rails, and; (2) identify design elements (e.g., elevation, material and methods used to construct earthen islands) that should be adjusted in future earthen island construction phases to maximize the high tide habitat function of the islands. This monitoring report integrates the September- October 2014 data with habitat elevation data collected immediately following construction (H. T. Harvey & Associates 2013a & 2014) and habitat elevation and vegetation monitoring collected in mid-May 2013, approximately 5 months after installation of the year 1 islands (H. T. Harvey & Associates 2013c).

1.4 Refuge Island Design Elevation

Year 1 and Year 2 refuge island tops were designed to be constructed at +1.0 ft above Mean Higher High Water (MHHW) and +1.3 ft above MHHW, respectively. Year 2 islands were built slightly higher than year 1 islands because we observed a strong correlation between island elevation and gumplant survival on the year 1 islands, 5 months after construction (H. T. Harvey & Associates 2013c).



The elevations of refuge island tops were designed to rapidly create high quality rail refugia dominated by gumplant, while remaining below the High Tide Line of the individual marsh sites. Field surveys and literature review conducted by H. T. Harvey & Associates found that gumplant in the San Francisco Estuary grows from -0.75 ft below to +2.21 ft above MHHW, with an average range of -0.10 below to + 0.82 ft above MHHW. The island top elevations were set such that following short term settlement (1-2 years) the site would still be within the mid-upper elevation range suitable for gumplant. Islands were expected to settle by approximately -0.5 ft to an island top elevation of approximately +0.5 ft above MHHW for year 1 islands and +0.8 ft above MHHW for year 2 islands.



Section 2.0 Methods

H. T. Harvey & Associates’ restoration ecologists, G. Archbald and K. Schott monitored the 22 refuge islands on 10, 11, 16, 23, 26 September and 9 October 2014. Refuge islands at Arrowhead Marsh, Belmont Slough North, Belmont Slough South, Bunker Marsh, Cogswell Marsh, Cooley Landing, and MLK/New Marsh were accessed by foot at low tide for monitoring. Bird Island and Bair Island sites were accessed during high tides to allow access to the refuge island sites via an aluminum workboat.

2.1 Habitat Elevation

2.1.1 Habitat Elevation Monitoring

Habitat elevation monitoring was designed to measure settlement of refuge islands and changes in the depth of excavation areas. Monitoring was conducted along permanent elevation transects established along the long axis of each refuge island and excavation area. Transects are marked by two PVC (or rebar) stakes installed at the ends of each island and excavation area. Transects were re-occupied for monitoring by stretching a measuring tape between the two marking stakes. During monitoring, spot elevations were collected every 3 feet and at topographic hinge points (e.g., top of slope, mid-slope) along each refuge island and excavation area. Measurements collected along the top of the island were averaged to determine the island top elevation. The depth of the excavation area was determined by averaging the elevations collected at the bottom of excavation area. Elevations were measured using a Leica Rugby 50 laser level and stadia rod relative to an elevation control stake set at MHHW installed at each refuge island location prior to construction (H. T. Harvey & Associates 2012 & 2013b).

2.1.2 Consolidation/settlement

Consolidation/settlement refers to the process by which islands decrease in elevation over time and includes both consolidation of material (e.g., marsh mud) placed on the marsh plain and the settlement of the island into the marsh plain. Percent consolidation/settlement provides a metric to compare elevation change between refuge islands. The percent consolidation/settlement of each island was calculated as the [height of the island above the marsh plain during September-October 2014 monitoring] / [as-built height of the island above the marsh plain following construction] * 100. The height of the marsh plain at each island site was determined by averaging elevation measurements collected with an RTK-GPS every 5 ft across the island fill site prior to construction (H. T. Harvey & Associates 2012 & 2013b).



2.2 Vegetation

Vegetation monitoring includes a survey of gumplant height and survival on each refuge island, a visual estimation of vegetation cover by species on the islands and in excavation areas, and notes on non-native plant recruitment.

2.2.1 Refuge Islands

2.2.1.1 Gumplant Survival

Approximately 58 gumplant plantings were installed on each island in year 1 and year 2. Year 1 gumplant plantings were provided by the Watershed Nursery in D-40 containers (2.5 in diameter x 10 in deep); gumplant plantings in Year 2 were provided by the Watershed Nursery in 1-gallon containers (6 in diameter x 7 in deep). The number of plants installed on each island was counted during as-built gumplant height surveys following planting. Gumplant quantities installed were recorded separately for 3 topographic positions on each island: (1) on the island top, (2) on the marsh plain side of the island, and (3) on the tidal slough channel side of the island. Gumplant was installed on island side slopes within the upper 2/3 of the island’s vertical profile; the lower 1/3 of the island side slopes was left unplanted. During annual monitoring, the number of living gumplant plants on each island was counted within each topographic position. Gumplant plantings were counted as “alive” if green leaves were present. Survival was calculated by dividing the number of living plants by the initial number of plants installed within each topographic position and for each island as a whole. The effect of topographic position on gumplant survival was evaluated by graphing average gumplant heights by topographic position with standard error bars in Microsoft Excel. Average values which differed by more than the sum of the standard errors associated with the average values were interpreted as exhibiting a substantive difference between treatments (i.e., non-overlapping error bars were interpreted as having a substantive effect and overlapping error bars were interpreted as no effect).

2.2.1.2 Gumplant Heights

The heights of all living gumplant plants were measured as the vertical distance between the tallest green leaf and the island surface. Gumplant heights were recorded separately within the topographic positions described above. Average gumplant heights were calculated by topographic position and by island. The effect of topographic position on gumplant height was evaluated in the same way as described above for gumplant survival.

2.2.1.3 Qualitative Observations

The approximate percent vegetation cover of vegetation on each earthen island was visually estimated and all native and non-native plant species present on the island were noted. The approximate percent cover of hybrid Spartina within 10 ft of each island was visually estimated.



2.2.2 Excavation Areas

2.2.2.1 Qualitative Observations

We estimated the percent cover and recorded the species of plants established on the side slopes and bottom of the excavation areas.

2.3 Gumplant Survival versus Refuge Island Elevation

Analysis of abiotic factors hypothesized to affect gumplant establishment (e.g., elevation [as a proxy for hydroperiod], soil pH, soil salinity) following year 1 monitoring suggested that elevation is a key driver of gumplant success on refuge islands (H. T. Harvey & Associates 2013b). Therefore, regression analysis (in Microsoft Excel) was used to evaluate the strength of the relationship between gumplant survival and year 1 and year 2 island elevations relative to MHHW.

2.4 Photo-documentation

Earthen islands and excavation areas were photographed from fixed locations (Table 2) following construction and again in September- October 2014. The longitudinal profile of most islands was also photographed in September- October 2014. Table 2. Photo-documentation Locations

Photopoint Description

1 View from the control stake to the excavation area

2 View from the control stake to between the earthen island and the excavation area

3 View from the control stake to the earthen island

4 View from the foot of the earthen island facing downstream

5 View from the foot of the earthen island facing upstream

6 View from the foot of the excavation area facing upstream



Section 3.0 Results and Discussion

3.1 Habitat Elevation

3.1.1 Refuge Island Elevations

3.1.1.1 Year 1 Islands

Approximately 21 months after construction, the average elevation of year 1 refuge islands was 0.50 ± 0.08 ft above MHHW (Figure 2). Year 1 island elevations ranged from +0.19 ft above MHHW at Belmont Slough South to +0.74 ft above MHHW at MLK/New Marsh (Table 2). On average, year 1 islands have decreased by -0.42 ft from the as-built elevation due to consolidation/settlement. This equates to 23% consolidation/settlement over approximately 2 years (Table 2).

Figure 2. Year 1 and Year 2 refuge island average elevations

(+/- SE) over time. On average among year 1 islands, island tops and the upper ~0.6 ft of the side slopes are within the typical vertical range for gumplant (-0.10 ft to +0.82 above MHHW).


Approximately 9 months after construction, the average elevation of Year 2 refuge islands was 0.89 ± 0.05 ft above MHHW (Figure 2). The elevation of year 2 islands ranged from +0.52 ft above MHHW at Arrowhead Marsh (ARH1) to +1.10 ft above MHHW at Cogswell Marsh (COGC1) (Table 3). Year 2 refuge island elevations have decreased on average by -0.34 ft from the as-built condition. This equates to 18% consolidation/settlement (Table 3). On average, year 2 refuge island tops and the upper 1 foot of the side slopes are within the typical vertical range for gumplant.



9

Table 3. Refuge Island and Excavation Area Elevations

1 Estimated as-built elevation; the elevation of BELS1 was measured at 0.48 ft above MHHW 2 weeks after construction. 2 Year 1 refuge islands were built in December 2012- January 2013. Year 2 refuge islands were built in December 2013- February 2014.

Marsh Year Built2

Island Number

Island Elevation Relative to MHHW (ft)

Total As-Built Height of Fill Above Marsh Plain (ft)

Change in Top of Island Elevation (ft) from As-Built

Percent Consolidation/Settlement

Excavation Area Elevation Relative to MHHW (ft)

Change in Excavation Depth (ft) from As-built

Design As-built2

May 2013

Sept/Oct 2014

As-Built2

May 2013

Sept/Oct 2014

Bair Island Year 1 BAIR1 1.0 0.88 0.60 0.54 1.87 -0.34 18.2% -2.83 -2.68 -2.52 +0.31

Belmont Slough N Year 1 BELN1 1.0 1.00 0.44 0.37 1.99 -0.63 31.7% -2.23 -2.31 -1.16 +1.07

Belmont Slough S Year 1 BELS1 1.0 0.91 0.22 0.19 1.91 -0.71 37.2% -2.85 -2.62 -2.22 +0.63

Bird Island Year 1 BIRD1 1.0 0.90 0.57 0.49 1.63 -0.41 25.2% -2.78 -2.60 -2.07 +0.71

Cooley Landing Year 1 COOL1 1.0 0.98 0.71 0.66 1.7 -0.32 18.8% -1.34 -1.35 -0.98 +0.36

MLK Marsh Year 1 MLK1 1.0 0.87 0.73 0.74 1.83 -0.13 7.1% NA NA

Arrowhead Marsh Year 2 ARH1 1.3 1.06 0.52 1.86 -0.54 29.0% -2.2 -2.09 +0.11

Arrowhead Marsh Year 2 ARH2 1.3 1.26 0.64 1.92 -0.62 32.3% -2.2 -2.11 +0.09

Bair Island Year 2 BAIR2 1.3 1.22 0.79 2.10 -0.43 20.5% -2.78 -2.67 +0.11



Bunker Marsh Year 2 BUNK1 1.3 1.10 0.8 1.62 -0.30 18.5% -2.44 -2.17 +0.27

Bunker Marsh Year 2 BUNK2 1.3 1.31 0.99 1.93 -0.32 16.6% -2.39 -1.79 +0.60

Cogswell Marsh B Year 2 COGB1 1.3 1.24 1.03 1.39 -0.21 15.1% -2.17 -1.75 +0.42



Cogswell Marsh C Year 2 COGC1 1.3 1.38 1.10 2.12 -0.28 13.2% -2.14 -1.75 +0.39



Cooley Landing Year 2 COOL2 1.3 1.32 1.00 1.76 -0.32 18.2% -2.32 -1.89 +0.43

MLK Marsh Year 2 MLK2 1.3 1.39 1.09 2.3 -0.30 13.0% NA NA

MLK Marsh Year 2 MLK3 1.3 1.25 1.06 2.03 -0.19 9.4% NA NA

Average of Year 1 islands 1.0 0.92 0.55 0.50 1.82 -0.42 23.0% -2.41 -2.31 -1.79 +0.62

Average of Year 2 Islands 1.3 1.23 0.89 1.88 -0.34 18.0% -2.19 -1.95 +0.24

3.1.1.3 Consolidation/Settlement

The amount of consolidation/settlement varied between refuge islands, from 7.1% at MLK/New Marsh (MLK1) to 37.2% at Belmont Slough South (Table 1). The difference in consolidation/settlement between islands is likely the result of (1) the initial moisture content (or conversely the initial bulk density) of material used for construction and (2) the stability of the underlying marsh substrate. The greatest consolidation/settlement occurred at islands where sediment used for construction appeared visibly saturated during construction (e.g., at Belmont Slough and Arrowhead Marsh). By contrast, consolidation/settlement was lowest at island sites where material for construction appeared relatively dry and the substrate was firm underfoot during construction (e.g. at MLK/New Marsh and Cogswell Marsh). Most consolidation/settlement of islands appears to have occurred within the first few months following construction. For example, Year-1 islands decreased in elevation by -0.34 ft in the first 5 months after construction but only -0.05 ft additionally over the next 16 months (Figure 2).

3.1.2 Excavation Areas

3.1.2.1 Year 1 Excavation Areas

On average, +0.62 ft of sediment accreted in year 1 excavation areas over 21 months (Figure 3). Sediment accretion ranged from +0.31 ft at Bair Island (BAIR1) to +1.07 ft at Belmont Slough North (BELN1) (Table 1). This depth of sediment accumulation is similar to sedimentation rates observed in restored south bay salt ponds at similar elevations. For example, sediment accumulated at rates ranging from about 0.1 ft to 0.4 ft per year within Pond A21 (Fremont, CA) at 5 ft NAVD88 (Callaway et al 2013), an elevation equivalent to refuge island excavation areas during the monitoring period (4.6 to 5.2 ft NAVD88). These results show that year 1 excavation areas are recovering elevation lost from sediment excavation.

3.1.2.2 Year 2 Excavation Areas

On average, +0.24 ft of sediment accreted in year 2 excavation areas over 9 months (Figure 2). Sediment accretion ranged from +0.00 ft at Cogswell Marsh (COGB3) to +0.60 ft at Bunker Marsh (BUNK2) (Table 1). No relationship was found between excavation area depth and sediment accretion, suggesting that variability in sedimentation rates between marshes may influence sedimentation rate more than excavation area depth alone. Results show that year 2 excavation areas are rapidly recovering elevation lost from sediment excavation.



Figure 3. Year 1 and Year 2 excavation area average

depth (+/- SE) over time.

3.2 Vegetation

3.2.1 Gumplant Survival


Gumplant survival on the year 1 refuge islands averaged 27.1% in September-October 2014, a decline from

62% average survival in May 2013 (Figure 4). Gumplant survival ranged from 0.0% at Belmont Slough North

and Bird Island (islands built from marsh sediment), to 77.6% at MLK/New Marsh where islands were

constructed using terrestrial clay soil. Among islands constructed using marsh sediment, survival was highest

at Bair Island (BAIR1) and Cooley Landing (COOL1) (Table 4).

There was no difference between average gumplant percent survival whether plants were installed on the top

or side slopes of the island (Figure 4, Table 4). Interim year 1 monitoring (May 2013) found that survival was

higher on island tops (average = 76.3%) than on earthen island sides (average = 53.9%), however, this trend

did not persist in September-October 2014.



Figure 4. Year 1 Refuge Island Average Gumplant Survival (+- SE)

Over Time By Topographic Position

Figure 5. Year 2 Refuge Island Gumplant Average Survival (+/- SE)

Over Time By Topographic Position


Gumplant survival on the year 2 refuge islands averaged 83.8% 9 months after construction; 21.8% higher

average survival than seen on year 1 islands 5 months after construction (Figures 4 and 5). Two factors may

explain the higher survival of gumplant on year 2 islands: (1) gumplant was planted in 1-gallon container

plants on year 2 islands versus in narrower D-40 containers on year 1 islands. The large container size (hence

larger volume of nursery soil) may have reduced transplant shock associated with planting gumplant into

saline marsh sediment, and, (2) year 2 islands were built +0.3 ft higher than year 1 islands. This additional

elevation may have reduced inundation stress associated with regular tidal inundation and thereby increased

gumplant survival.



13

Table 4. Refuge Island Gumplant Survival

Marsh Year Built 1 Island Number

Average Gumplant Survival Average Top of Island Gumplant Survival

Average Channel Side Gumplant Survival

Average Marsh Plain Side Gumplant Survival (%)

May 2013 Sept/Oct 2014 May 2013 Sept/Oct 2014 May 2013 Sept/Oct

2014 May 2013 Sept/Oct 2014

Bair Island Year 1 BAIR1 46.6% 37.9% 68.2% 50.0% 42.9% 35.3% 37.5% 29.4% Belmont Slough N Year 1 BELN1 58.0% 2.4% 78.9% 0.0% 47.1% 7.7% 46.2% 0.0% Belmont Slough S Year 1 BELS1 32.8% 11.5% 75.0% 4.0% 5.6% 11.8% 17.6% 25.0% Bird Island Year 1 BIRD1 55.2% 1.9% 51.7% 0.0% 50.0% 6.0% 55.6% 0.0% Cooley Landing Year 1 COOL1 82.8% 31.4% 84.0% 26.1% 94.7% 33.3% 56.3% 38.5% MLK Marsh Year 1 MLK1 96.6% 77.6% 100.0% 68.2% 81.3% 87.5% 100.0% 88.9%

Arrowhead Marsh Year 2 ARH1 68.0% 65.2% 86.7% 75.0% Arrowhead Marsh Year 2 ARH2 52.2% 26.7% 68.8% 60.0% Bair Island Year 2 BAIR2 95.7% 100.0% 92.9% 90.0% Bair Island Year 2 BAIR3 91.5% 86.4% 92.3% 100.0% Bair Island Year 2 BAIR4 85.2% 95.2% 100.0% 68.4% Bunker Marsh Year 2 BUNK1 85.4% 90.5% 92.3% 62.5% Bunker Marsh Year 2 BUNK2 92.0% 83.3% 91.6% 100.0% Cogswell Marsh B Year 2 COGB1 76.5% 61.1% 88.2% 81.3% Cogswell Marsh B Year 2 COGB2 86.4% 78.9% 84.6% 100.0% Cogswell Marsh B Year 2 COGB3 89.6% 93.3% 76.5% 100.0% Cogswell Marsh C Year 2 COGC1 87.8% 70.6% 94.1% 100.0% Cogswell Marsh C Year 2 COGC2 89.8% 78.9% 92.3% 100.0% Cogswell Marsh C Year 2 COGC3 93.8% 95.0% 100.0% 85.7% Cooley Landing Year 2 COOL2 92.2% 84.6% 100.0% 100.0% MLK Marsh Year 2 MLK2 76.0% 93.3% 68.8% 68.4% MLK Marsh Year 2 MLK3 79.6% 77.3% 92.3% 66.7%

Average of Year 1 Islands 62.0% 27.1% 76.3% 24.7% 53.6% 30.3% 52.2% 30.3% Average of Year 2 Islands 83.8% 80.0% 88.8% 84.9%

1 Year 1 refuge islands were built in December 2012- January 2013. Year 2 refuge islands were built in December 2013- February 2014.

Gumplant survival on year 2 islands ranged from 52.2% survival at Arrowhead Marsh (ARH2) to 95.7%

survival at Bair Island (BAIR 2). In contrast to year 1 islands, gumplant survival on many of the refuge islands

constructed with marsh mud was higher than survival at MLK/New Marsh where islands were constructed

using terrestrial fill (Table 2).

3.2.2 Gumplant Height


Average gumplant height increased among year 1 islands relative to the May 2013 monitoring period (Figure 6; Table 3). Gumplant heights did not differ substantially with topographic position within each monitoring period. However, channel side gumplant heights increased substantially between the May 2013 and September-October 2014 monitoring periods (Figure 6).

Figure 6. Year 1 Refuge Island Gumplant Average Height (+/- SE)

Over Time by Topographic Position



15

Table 5. Gumplant Heights

Marsh Year Built

Island Number

Average Gumplant Height (ft)

Average Top of Island Gumplant Height (ft)

Average Channel Side Gumplant Height (ft)

Average Marsh Plain Side Gumplant Height (ft)

As-Built May 2013

Sept/Oct 2014

As-Built May 2013

Sept/Oct 2014

As-Built May 2013

Sept/Oct 2014

As-Built

May 2013

Sept/Oct 2014

Bair Island Year 1 BAIR1 1.57 0.94 1.40 1.54 1.43 1.41 1.59 1.42 1.60 1.59 1.15 1.13

Belmont Slough N Year 1 BELN1 1.42 1.04 1.58 1.50 1.19 NA 1.45 0.95 1.58 1.28 0.77 NA

Belmont Slough S Year 1 BELS1 1.40 1.09 1.41 1.47 1.21 0.83 1.31 1.20 1.08 1.39 0.50 1.81

Bird Island Year 1 BIRD1 1.36 1.36 1.00 1.32 0.87 NA 1.40 0.96 1.00 1.36 1.04 NA

Cooley Landing Year 1 COOL1 1.38 1.36 1.49 1.44 1.36 1.56 1.34 1.25 1.38 1.33 1.59 1.52

MLK Marsh Year 1 MLK1 1.34 1.61 1.73 1.30 1.69 1.72 1.40 1.58 1.66 1.35 1.54 1.79

Arrowhead Marsh Year 2 ARH1 2.32 1.47 2.21 1.18 2.57 1.87 2.23 1.51

Arrowhead Marsh Year 2 ARH2 2.26 1.52 2.21 1.29 2.36 1.53 2.22 1.60

Bair Island Year 2 BAIR2 2.40 1.76 2.32 1.52 2.45 2.26 2.54 1.68



Bunker Marsh Year 2 BUNK1 2.20 1.84 2.27 1.58 2.16 1.92 2.16 2.16

Bunker Marsh Year 2 BUNK2 2.44 1.70 2.39 1.57 2.51 1.79 2.47 1.81

Cogswell Marsh B Year 2 COGB1 2.41 1.70 2.30 1.36 2.50 1.84 2.43 1.82



Cogswell Marsh C Year 2 COGC1 2.43 2.06 2.39 2.22 2.43 1.97 2.47 2.03



Cooley Landing Year 2 COOL2 2.26 1.40 2.30 1.29 2.11 1.59 2.40 1.31

MLK Marsh Year 2 MLK2 2.30 2.20 2.27 1.88 2.40 2.22 2.24 2.53

MLK Marsh Year 2 MLK3 2.16 2.22 1.99 1.93 2.41 2.51 2.20 2.37

Average of Year 1 islands 1.41 1.23 1.44 1.43 1.29 1.38 1.42 1.23 1.38 1.38 1.10 1.56

Average of Year 2 Islands 2.37 1.79 2.37 1.64 2.41 1.89 2.36 1.89


Average gumplant height decreased on year 2 islands from the as-built condition (Figure 7; Table 3). This is explained by the observation that gumplant leaves frequently died-back on plantings and were replaced by leaves of lower height which re-sprouted from the base. Gumplant transplanted into saline conditions often experience transplant shock and initially die back above ground (pers. observation). Moreover, the nursery produced substantially taller gumplant container plants in year-2 compared to year-1 (Table 3- as-built height); these year-2 container plants likely had a lower root: shoot ratio compared to year-1 plants. This difference could also have contributed to the increased dieback of aboveground gumplant stems relative to year-1. Topographic position affected gumplant height. Gumplant height declined about 0.25 ft more on island tops than on side slopes (Figure 7; Table 3). This may be the result of increased stress on island tops. Alternatively, lower height could indicate plants are allocating more resources to below ground root production relative to plants installed lower in the tidal frame.

Figure 7. Year 2 Refuge Island Gumplant Average Height

(+/- SE) Over Time by Topographic Position

3.2.3 Qualitative Percent Cover

3.2.3.1 Year 1 and Year 2 Refuge Islands

There was robust growth of perennial pickleweed (Salicornia pacifica) from the transplanted sod on all earthen islands. Substantial growth of other marsh plants present in marsh sod was also observed, including saltgrass (Distichlis spicata), fleshy jaumea (Jaumea carnosa), and alkali heath (Frankenia salina). Survival of saltgrass from plantings also appeared high. Saltgrass was observed spreading from saltgrass plantings installed on both year 1 and year 2 islands. No upland plants were found on any refuge islands.



Non-native salt marsh plants, Russian thistle (Salsola soda) and Algerian sea lavender (Limonium ramosissimum subsp. provinciale), were found and removed during monitoring at COGB1 and COGC3, respectively (1 single plant in both cases). Invasive hybrid Spartina was found in trace amounts on the following islands: COGC3, MLK1, MLK2, and MLK3.

Hybrid Spartina was present within 10 ft of the refuge island at the following islands: BAIR1 (<1% cover), BAIR 2 (15% cover), BAIR 3 (25% cover), BAIR 4 (10% cover), BELS1 (10%), BUNK1 (1% cover), BUNK2 (20% cover), COGB1 (7% cover), COGB3 (30% cover), COGC1 (present- no cover value), COGC2 (<1% cover), COGC3 (<1%), MLK1 (60% cover), MLK 2 (60% cover) and MLK3 (80% cover). Table 4 provides the percent cover of tidal marsh plants observed on each island. Table 6. Percent vegetation cover in refuge island excavation and fill areas

Marsh Year Built Island Number Vegetation Cover

Excavation Area Refuge Island

Bair Island Year 1 BAIR1 Not visible 98%

Belmont Slough N Year 1 BELN1 40% 97%

Belmont Slough S Year 1 BELS1 10% 100%

Bird Island Year 1 BIRD1 10% 90%

Cooley Landing Year 1 COOL1 90% 98%

MLK Marsh Year 1 MLK1 NA 93%

Arrowhead Marsh Year 2 ARH1 36% 72%

Arrowhead Marsh Year 2 ARH2 60% 91%

Bair Island Year 2 BAIR2 35% 85%



Bunker Marsh Year 2 BUNK1 15% 92%

Bunker Marsh Year 2 BUNK2 35% 90%

Cogswell Marsh B Year 2 COGB1 35% 95%



Cogswell Marsh C Year 2 COGC1 15% 85%



Cooley Landing Year 2 COOL2 40% 85%



Average of Year 1 islands 38% 96%

Average of Year 2 Islands 33% 88%



3.2.3.2 Year 1 and Year 2 Excavation Areas

Excavation areas ranged from low cover to well vegetated (e.g., 10% to 90% cover; Table 4). Plant cover was primarily perennial pickleweed. Fleshy jaumea, saltgrass, and hybrid Spartina were also present in some excavation areas. Cover was higher along most excavation area side slopes and lower at the bottom of excavation areas. Sites with lower cover tended to be the sites at lower elevations. Salt marsh cover is anticipated to continue increasing as these areas aggrade.

Hybrid Spartina cover in excavation areas were as follow: ARH1 (1% cover), ARH2 (< 1% cover), BAIR2 (1% cover), BUNK2 (1% cover), COGB3 (5% cover), COGC1 (5% cover), COGC3 (2% cover), and BELS1 (2% cover).

3.3 Gumplant Survival versus Island Elevation

Gumplant survival was greater at sites located higher in the tidal frame (Figure 8). Elevation relative to MHHW was a strong predictor (R2 = 0.68) of gumplant survival. Gumplant survival was approximately 80% and above at earthen islands sites with tops situated at or above approximately +0.70 ft above MHHW.

Figure 8. Gumplant Survival Versus Elevation (Year 1 islands are shown

in green, year 2 islands are shown in blue)

3.4 Photo-documentation

Photo-documentation comparing earthen islands and excavation areas in December-January 2013 (As-built for year 1 islands) and December-February 2014 (As-built for year 2 islands) versus September-October 2014 is provided in Appendix C.



3.5 Status of Earthen Island Function

Year 1 and year 2 refuge islands were expected to settle following construction to approximately +0.5 ft above MHHW and +0.8 ft above MHHW (respectively). With establishment of 2-3 ft tall gumplant, this will provide cover for rails during most high tide events. We found that 4 of the 6 year 1 islands (and all year 2 islands) remained above +0.5 ft above MHHW. Thirteen of the 16 year 2 islands remained above +0.8 ft above MHHW. Therefore, 20 of the 22 islands were within a suitable elevation range to provide the target high tide refuge cover for rails when gumplant establishes. Gumplant was (on average) 1.4 ft tall on year 1 islands and 1.7 ft tall on year 2 islands. The Year 1 islands with high gumplant cover (MLK1 and BAIR1) have developed sufficient gumplant canopy architecture to provide high and moderate cover (respectively) for rails. Replanting of gumplant will be needed on 4 of the 6 year 1 islands to develop sufficient cover for rails. As expected, the recent gumplant plantings on year 2 islands are recovering from transplant shock and have not yet developed gumplant canopy architecture that would provide cover for rails with the exception of MLK2 and MLK3 islands, where gumplant establishment has occurred faster due to the use of terrestrial soil for island construction. We anticipate that 1-3 more growing seasons will be needed for gumplant on most year 2 islands to mature enough to provide good cover for rails. On nearly all refuge islands, perennial pickleweed dominated vegetation provides cover to a height of approximately 0.5-1 ft above the island ground surface, providing suitable cover for the salt marsh harvest mouse and some cover for rails.



Section 4.0 Design, Maintenance and Monitoring Recommendations

4.1 Refuge Island Design

We provided the following recommendations for island design to the Conservancy in November 2014. These refuge island design recommendations were incorporated in the construction design for 21 additional refuge islands which were constructed in the December-January of 2014-2015.

1. Increase constructed earthen island top elevations to 1.5 - 1.7 ft above MHHW. Gumplant percent survival in year 1 and year 2 is strongly correlated with refuge island elevation relative to MHHW. Additionally, we have observed along the margins of tidal marshes, that gumplant cover is typically highest near and above the high tide line. Drainage and desiccation patterns on refuge islands are likely more similar to conditions at the margins of tidal marshes than conditions for gumplant along tidal slough channels where gumplant grows lower in the tidal frame (and where survival may be facilitated by rapid drainage of pore water in marsh sediment due to channel proximity). Therefore, to sustain gumplant survival as islands settle, we recommend increasing the height of island tops to be slightly below the high tide line.We expect islands constructed to 1.5- 1.7 ft above MHHW to settle to approximately 1.1- 1.4 ft above MHHW in the first year. This increased height is likely to increase gumplant survival rates. 2.Experimentally incorporate terrestrial soil in gumplant planting pits. Gumplant canopy structure has established most rapidly on year 1 and year 2 islands built using terrestrial soil (at MLK/New Marsh). This may be due to lower salinity stress on gumplant seedlings, since the terrestrial soil salinity was low at the time of plant installation. Therefore, we recommend experimentally installing gumplant in planting pits amended with terrestrial clay soil on refuge islands otherwise constructed using marsh sediment. This treatment has the potential to speed establishment of dense gumplant canopies on refuge islands.

4.2 Future Planning, Maintenance and Monitoring

We have the following island recommendations for future island planning, maintenance and monitoring:

1. Plan and build islands to ensure target elevation. Gumplant survival has been lowest on islands which are relatively low in the tidal frame. Island consolidation/settlement appears to be greatest when islands are constructed using low bulk density marsh sediment (e.g., at Belmont Slough and Arrowhead Marsh). To avoid constructing islands below the design elevation, island locations could be ground-truthed earlier in the site selection/permitting process to avoid construction in areas with relatively unconsolidated sediments. This would require USFWS permission for restoration ecologists



to access marshes during Ridgway’s rail breeding season. Alternately, islands built using low bulk density material could be built higher than the design grade to offset anticipated consolidation/settlement.

2. Replant gumplant on selected islands. Gumplant was intentionally “over planted” on refuge islands during construction because some gumplant mortality was anticipated. However, gumplant survival has been exceptionally low on some islands necessitating replanting to develop the target high tide refuge habitat. We recommend the Conservancy replant salt-hardened gumplant in 1-gallon container plants in locations and approximate quantities listed below in the Table 7. We hypothesize that gumplant survival was low on these islands due to their relatively low elevations and, therefore, increased inundation stress on gumplant plantings. However, these islands remain within the tidal range that gumplant establishes along tidal slough channels. Furthermore, Year 1 islands were planted with gumplant from D-16 container stock. Replanting using 1-gallon gumplant container plants may increase gumplant survival. Finally, installing gumplant into soil pits amended with terrestrial soil (as described in Section 4.1) may also increase gumplant survival. If terrestrial soil treatments increase gumplant survival on Year 3 islands, this treatment applied during replanting on Year 1 and 2 islands. Table 7. Gumplant Replanting Recommendations

Marsh Year Built Island Number Recommended Gumplant Replanting Quantities

Bair Island Year 1 BAIR1 28

Belmont Slough N Year 1 BELN1 49

Belmont Slough S Year 1 BELS1 46

Bird Island Year 1 BIRD1 53

Cooley Landing Year 1 COOL1 34



Total 252

3. Incorporate Simple, Rapid Field Measurements of Soil Parameters Into Year-3 Island Monitoring. Conduct rapid field measurements of soil paste salinity and pH on a sub-set of refuge islands compared to adjacent natural stands of gumplant to better understand the effect of island construction on soil parameters most likely to affect gumplant establishment. For example, soil paste salinity and pH in the rooting zone could be compared between gumplant installed with and without terrestrial soil.



Section 5.0 Literature Cited

Bay Conservation and Development Commission. 2012. BCDC Permit No. M2012.016.00. Issued 14 December 2012.

Callaway JC, Schile LM, Borgnis EL, Busnardo M, Archbald G and R Duke. Sediment dynamics and

vegetation recruitment in newly restored salt ponds: Final report for Pond A6 sediment study. Submitted to Resources Legacy Fund and the South San Francisco Bay Salt Pond Restoration Project. 26 July 2013.

H. T. Harvey & Associates. 2012. Invasive Spartina Project Pilot Earthen Island Construction Notes to

Contractors. Prepared for the California Coastal Conservancy. Dated 10 December 2012. Project #3352-01.

H. T. Harvey & Associates. 2013a. Lessons Learned from Construction of California Clapper Rail Earthen

High Tide Refuge Islands. Project #3352-01. Technical Memorandum submitted to the California State Coastal Conservancy.

H. T. Harvey & Associates. 2013b. San Francisco Estuary Invasive Spartina Project Earthen Island

Construction Notes to Contractors. Prepared for the California Coastal Conservancy. Dated 21 November 2013. Project #3415-03.

H. T. Harvey & Associates. 2013c. San Francisco Estuary Invasive Spartina Project Pilot Earthen Islands

Interim Year-1 Monitoring Report. Submitted to the California Coastal Conservancy. Dated 14 June 2013. Project 3415-02.

H. T. Harvey & Associates. 2014. 2013 -2014 San Francisco Estuary Invasive Spartina Project high tide refuge

island construction update. Memorandum submitted to the California State Coastal Conservancy dated 9 April 2014. Project #3415-04.

United States Geologic Survey. 1983. South San Francisco Bay Tidal Marsh Vegetation and Elevation Surveys

– Corkscrew Marsh, Bird Island and Palo Alto Baylands, California, 1983. U.S. Geological Survey, Sacramento, CA.

United States Department of Agriculture. 1957. SOIL: The Yearbook of Agriculture 1957. The United States

Government Printing Office, Washington D.C. United States Fish and Wildlife Service. 2012a. Formal Consultation for the Proposed San Francisco Estuary

(Estuary) Invasive Spartina Project (Biological Opinion). Dated 21 August 2012. United States Fish and Wildlife Service. 2012b. File Number 2003-27819S. Dated 14 December 2012.



Appendix A. Lessons Learned From Construction of California Clapper Rail Earthen High Tide Refuge Islands

Invasive Spartina Project Pilot Earthen Island Interim Year-1 Monitoring

A-1 H. T. Harvey & Associates 16 April 2015


Invasive Spartina Project Pilot Earthen Island Construction Notes to Contractors

Prepared by:


10 December, 2012 Project # 3352-01

Invasive Spartina Project, Pilot Earthen Islands Construction Notes to Contractors i

H. T. Harvey & Associates 12 December 2012

Table of Contents

Table of Contents ................................................................................................................................................................ i Construction Notes ............................................................................................................................................................ 1

Construction Work Window ........................................................................................................................................ 1 Location ........................................................................................................................................................................... 1 Elevation Control Stake/ Grade Control .................................................................................................................. 2 Excavation Area ............................................................................................................................................................. 2 Earthen Island Construction ........................................................................................................................................ 3 Planting ............................................................................................................................................................................ 3

Tables Table 1. Locations of Earthen Island, Excavation Areas and Elevation Control Stakes ....................................... 4 Table 2. Limits of Excavation Area ................................................................................................................................ 4 Table 3. Earthen Island Vertical Construction Dimensions ....................................................................................... 5 Table 4. Earthen Island Planimetric Construction Dimensions ................................................................................ 5 Table 5. Container Plant Quantities per Earthen Island ............................................................................................. 6 Figures Figure 1. Earthen Island Typical Plan View .................................................................................................................. 7 Figure 2. Earthen Island Typical Cross Section ............................................................................................................ 8 Figure 3. MLK/ New Marsh ........................................................................................................................................... 9 Figure 4. Belmont Slough South- Plan View Location .............................................................................................. 10 Figure 5. Belmont Slough North- Plan View Location ............................................................................................. 11 Figure 6. Bird Island- Plan View Location .................................................................................................................. 12 Figure 7. Cooley Landing- Plan View Location .......................................................................................................... 13 Figure 8. Bair Island North Quadrant West- Plan View Location ........................................................................... 14

Invasive Spartina Project, Pilot Earthen Islands Construction Notes to Contractors 1


Construction Notes

The following notes, tables and figures provide information to support construction of 6 pilot

earthen islands; one at each of the 6 following marsh locations: MLK/New Marsh, Belmont Slough

South, Belmont Slough North, Bird Island, Cooley Landing, and Bair Island North Quadrant West.

Construction Work Window

Excavation and fill placement shall be done when sediments are not inundated and prior to 1 February 2013. Ideally, the excavation of material and construction of the island will be completed during one low-tide cycle. If earthen island construction is not completed before the tide rises, measures such as tarping the excavated and salvaged materials will be employed to prevent the materials from entering the tidal waters and prevent erosion.

Location

Each pilot earthen island marsh location (with the exception of MLK/New Marsh) consists of an

earthen island fill area, an excavation area, and an elevation control stake; all within 20-30 feet (ft) of

each other and each marked with a 1.25 inch diameter white PVC post. The MLK/New Marsh site

consists of an earthen island and an elevation control stake. This site does not include an excavation

area because the earthen island will be constructed from clean, imported fill.

On the day of construction, an H. T. Harvey & Associates’ restoration ecologist will be present to

flag the footprints of the excavation and earthen island fill areas and point out the location of the

elevation control stake at each pilot island marsh location. However, the contractor is responsible

for being able to navigate to these locations in the absence of an H. T. Harvey & Associates

restoration ecologist. The geographic coordinates of these locations are provided in Table 1. In

addition, an ESRI shapefile (viewable in ArcMap) and a KMZ file (viewable in Google Earth) are

provided with this document. Figures 1 and 2 provide plan and cross-section views of a generalized

earthen island construction area (excluding the control stake). Figures 3 through 7 provide the

general location of pilot earthen island construction areas. Note that the artificial floating islands

shown in Figure 1 will be constructed by others (U.S. Geologic Survey Staff).



Elevation Control Stake/ Grade Control

The Contractor is responsible for grade control to meet the requirements in Tables 2, 3, 4 and

Figure 2. An elevation control stake is situated approximately 20-40 ft from each island location and

consists of a 1.25 inch diameter white PVC pipe with top of pipe cut at Mean Higher High Water

(MHHW). The location (latitude and longitude) of elevation control stakes are provided in Table 1

and the specific elevation (in ft NAVD88) of each control stake is provided by marsh location in

Table 2. The maximum depth of excavation and the height of island construction were determined

relative to the control stake elevation (Tables 2 and 3). Heavy equipment should be kept at least 10

ft from control stakes at all times and physical contact with control stakes should be avoided to

prevent control stake disturbance.

Excavation Area

Each island (with the exception of the MLK/New Marsh island) will be constructed from

approximately 6 to 15 cubic yards of bay mud material that will be excavated from an adjacent

vegetated slough channel bank (the excavation area) from a maximum area of 250 square feet (ft2)

(Figure 1). Prior to excavation, the top six vertical inches (0.5 ft) of the existing marsh vegetation,

root structure and sediment (marsh sod) will be salvaged from the surface of the excavation area and

1) planted on the earthen island after excavation is complete and 2) planted on the side slopes of the

excavation area after excavation is complete. At the site of bay mud excavation, the slough channel

segment will be contoured to create a low-elevation bench with 1 H: 1 V side slopes between the

unexcavated marsh plain and the excavated low-elevation bench. Table 2 provides the design grade

of the low elevation bench (i.e. the maximum depth of the low-elevation bench) in ft NAVD88 and

relative to MHHW (the height of control stake). The estimated vertical depth of sediment between

the existing marsh plain surface and the design grade of the low elevation bench is presented in

Table 2. During excavation and construction of the marsh island, the profile (vertical orientation) of

the excavated marsh sediments should be preserved to the extent feasible within the Contractor’s 1

to 2 day construction time and budget per site.

No excavation will be conducted at the MLK/New Marsh site.



Earthen Island Construction

The top six vertical inches (0.5 ft) of the existing marsh vegetation, root structure and sediment (mash sod) will be salvaged from the surface of the earthen island construction area and set aside, to be planted on the earthen island after fill placement is complete. Bay mud from the excavation area (or imported fill at the MLK/New Marsh site) will then be placed in the island footprint in such a way as to minimize air pockets in the fill material. After fill is complete, marsh sod salvaged from the earthen island construction area and from the excavation area (if additional marsh sod is needed to cover island) will be installed across the top and side slopes of the constructed earthen island to a finished design elevation of 1.0 ft above MHHW with 2 H: 1 V side slopes (Figure 2). The height of each island top relative to the marsh plain is specified in Table 3. The dimensions (length and width) of the island top and base are specified in Table 4. The top of the earthen island should be contoured to prevent water from ponding on the top of the island and the sediment and sod on the top and sides of the island lightly compacted to reduce erosion from tidal fluctuations before planting the island with container plants. The elevation of earthen islands will be verified via measurement (e.g., with a laser level) of the vertical difference between the control stake and top of island.

Planting

The portion of each island from 0.5 ft below MHHW (0.5 ft below top of control stake) to the top of the island will then be planted with marsh gumplant (Grindelia stricta) on 2 ft centers. Saltgrass (Distichlis spicata) will also be installed from container stock at all islands, with two plants next to every other marsh gumplant planting (Table 5). Plants should be installed in gaps between marsh sod clumps, to the extent feasible. Care should be taken to install plants with as much nursery soil around the roots of gumplant and saltgrass plantings as possible. Following planting, no air pockets should remain between installed plants and earthen island construction material.



Table 1. Locations of Earthen Island, Excavation Areas and Elevation Control Stakes

Pilot Island Marsh Location

GPS Coordinates (NAVD 88)

Earthen Island Center Point Excavation Area Center Point

Elevation Control Stake

Latitude Longitude Latitude Longitude Latitude Longitude

MLK/New Marsh*

37.73946 -122.2087854 NA NA 37.73947 -122.2087078


37.54251 -122.251722 37.54257 -122.2518235 37.54258 -122.251698


37.54648 -122.2524651 37.54645 -122.2523431 37.54641 -122.2524593

Bird Island 37.54944 -122.233597 37.54934 -122.2336451 37.54943 -122.2336852

Cooley Landing 37.47787 -122.1282943 37.47789 -122.1284818 37.47798 -122.1283378

Bair Island North Quadrant West

37.53918 -122.2192292 37.53908 -122.219072 37.53908 -122.2192819

* MKL/ New Marsh will be constructed from clean imported fill. Therefore, coordinates for an excavation area are not provided. Table 2. Limits of Excavation Area


Elevation of Top of Control Stake (Situated at MHHW) (ft NAVD88)

Maximum Excavation Depth (ft) Below MHHW

Maximum Depth of Excavation Below Existing Ground Surface (ft)

Total Maximum Excavation Area Surface Area (ft2)

MLK/New

Marsh*

6.46 NA NA NA

Belmont Slough South 6.99 2.99 2.03 250

Belmont Slough North 6.99 2.99 1.77 250

Bird Island 7.02 3.42 1.87 250

Cooley Landing 7.05 3.05 2.54 250


7.08 3.08 2.39 250

* MKL/New Marsh will be constructed from clean imported fill. Therefore, no excavation area dimensions are provided. Horticultural specifications for imported fill to the MLK/New Marsh island will be provided, but is not presenter herein.



Table 3. Earthen Island Vertical Construction Dimensions


Elevation of Top of Control Stake (Situated at MHHW) (ft NAVD88)

Height of Island Tops above MHHW (ft)

Design Elevation for Top of Islands (ft NAVD88)

Average Elevation of Ground Surface at Fill Site (ft NAVD88)

Average Fill Height above Ground Surface (ft NAVD88)

MLK/New Marsh 6.46 +1 7.46 5.50 1.96


6.99 +1 7.99 5.99 2.00


6.99 +1 7.99 6.00 1.99

Bird Island 7.02 +1 8.02 6.29 1.73

Cooley Landing 7.05 +1 8.05 6.50 1.55


7.08 +1 8.08 6.09 1.99

Table 4. Earthen Island Planimetric Construction Dimensions


Total Island Length Including Side Slopes (ft NAVD88)

Total Island Width Including Side Slopes (ft NAVD88)

Maximum Surface Area of Island Fill (ft2)

Length of Island Top At 1ft Above MHHW (ft)

Width of Island Top At 1ft Above MHHW(ft)

MLK/ New Marsh 25 10 250 17 2


25 10 250 17 2


25 10 250 17 2

Bird Island 28 9 250 21 2

Cooley Landing 31 8 250 25 2


25 10 250.0 17 2



Table 5. Container Plant Quantities per Earthen Island

Species Common Name

On-Center Spacing Quantity per Earthen Island

Total Quantity (5 islands)

Grindelia stricta gumplant 2 ft 58 348

Distichlis spicata saltgrass 2 plants installed adjacent to every other gumplant planting

58 348

0 2010

1 INCH = 20 METERS

Figure 3: USACE Jurisdictional Delineation -Pilot Islands Location at MLK New Marsh

Map produced: September 2012Imagery: Microsoft Bing Aerials

LEGEND

Survey Area (2.88 ac)

Pilot Island Location (1 Earthen + 1 Floating)

USACE Section 10/404 Jurisdictional Features

Wetland (2.74 ac)

Other Waters (0.14 ac)

PARDEE LN

JARPA Permit Application Materials

Be l m

o n tS

l o u g h

Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping,Aerogrid, IGN, IGP, and the GIS User Community

0 2010

1 INCH = 20 METERSFigure 4: USACE Jurisdictional Delineation -Pilot Island Location at Belmont Slough South

Map produced: September 2012Imagery: World Imagery, ESRI

LEGENDSurvey Area (2.79 ac)Pilot Island Location (1 Earthen + 1 Floating)Upland (0.06 ac)

USACE Section 10/404 Jurisdictional FeaturesWetland (2.17 ac)Other Waters (0.62 ac)

Belm

ont S

loughBeach Park Blvd


0 4020

1 INCH = 40 METERS

Figure 5: Island Location atBelmont Slough North

Map produced: September 2012Imagery: Microsoft Bing Aerials

LEGEND

Site Boundary

ISP

ISP

Non-Pilot Island Location (1 Earthen + 1 Floating)

2012 California Clapper Rail Detections (BySurvey Round)

2011 Invasive Spartina Cover

#

Foster City Blvd

SanFrancisco

Bay



0 2010

1 INCH = 20 METERS

Figure 6: USACE Jurisdictional Delineation -Pilot Island Location at Bird Island


LEGEND




Wetland (2.57 ac)


San Francisco Bay

BIRD ISLAND



0 2010

1 INCH = 20 METERS

Figure 7: USACE Jurisdictional Delineation -Pilot Island Location at Cooley Landing Central


LEGEND




Wetland (1.98 ac)


San Francisco Bay

TAR

TAST

BAY RD



0 2010

1 INCH = 20 METERS

Figure 8: USACE Jurisdictional Delineation - PilotIsland Location at Bair Island North Quadrant West


LEGEND




Wetland (2.24 ac)


Stei

nber

ger S

lough

San Francisco Bay


Appendix B. Invasive Spartina Project Pilot Earthen Island Construction Notes to Contractors


B-1 H. T. Harvey & Associates 16 April 2015


San Francisco Estuary Invasive Spartina Project

Earthen Island Construction Notes to Contractors

Project #3415-03

Prepared by:


Prepared for:

Ms. Marilyn Latta California Coastal Conservancy

1330 Broadway, Suite 1300 Oakland, CA 94612

21 November 2013

Invasive Spartina Project, Earthen Islands Construction Notes to Contractors i

H. T. Harvey & Associates 21 November 2013

Preparers Ron Duke, M.A., Principal-In-Charge Joe Howard, M.L.A., Principal, Landscape Architect Max Busnardo, M.S., Project Manager, Sr. Associate Restoration Ecologist Gavin Archbald, M.S., Restoration Ecologist

Invasive Spartina Project, Earthen Islands Construction Notes to Contractors ii


Table of Contents

Table of Contents ................................................................................................................................................................ i Overview ......................................................................................................................................................................... 1 Field Staking of Earthen Island Construction Features and Grade Control........................................................ 2 Earthen Island Construction Materials ...................................................................................................................... 3 Access .............................................................................................................................................................................. 4 Construction Work Window ........................................................................................................................................ 4 Measures to Protect Marsh during Construction ..................................................................................................... 4 Marsh Sod Harvest and Storage .................................................................................................................................. 5 Excavation Area ............................................................................................................................................................. 5 Earthen Island Construction ........................................................................................................................................ 5 Marsh Sod Installation .................................................................................................................................................. 6 Container Plant Installation .......................................................................................................................................... 6

Tables Table 1. Earthen Island Quantity by Tidal Marsh ........................................................................................................ 1 Table 2. Geographic Coordinates of Earthen Island Construction Features .......................................................... 2 Table 3. Control Stake Elevations ................................................................................................................................... 3 Table 4. Imported Soil Specifications for Earthen Island Construction at MLK Marsh and Arrowhead

Marsh ............................................................................................................................................................... 4 Table 5. Earthen Island Planimetric Construction Dimensions ................................................................................ 6 Table 6. Container Plant Quantities per Earthen Island ............................................................................................. 7 Figures Figure 1. Vicinity Map ....................................................................................................................................................... 8 Figure 2. Earthen Island Typical Plan View .................................................................................................................. 9 Figure 3. Earthen Island Typical Cross Section .......................................................................................................... 10 Figure 4. Arrowhead Marsh ........................................................................................................................................... 11 Figure 5. Bair Island ........................................................................................................................................................ 12 Figure 6. Bunker Marsh .................................................................................................................................................. 13 Figure 7. Cogswell Marsh ............................................................................................................................................... 14 Figure 8. Cooley Landing ............................................................................................................................................... 15 Figure 9. MLK Marsh ..................................................................................................................................................... 16

Invasive Spartina Project, Earthen Islands Construction Notes to Contractors 1


Overview The California Coastal Conservancy (Conservancy) plans to construct 16 earthen islands (referred to herein as islands or earthen islands) to provide habitat for the federally endangered California clapper rail (Rallus longirostris obsoletus) in San Francisco Bay tidal marshes. Construction of these islands combined with the 6 pilot islands constructed in winter 2012-2013, will fulfill the earthen island installation requirements of the U.S. Fish and Wildlife Service (USFWS) 2012 Biological Opinion for the Invasive Spartina Project (ISP). The 16 islands will be installed prior to 1 February 2014, during the clapper rail non-breeding season. The following notes, tables, and figures provide information to support construction of these islands. Two scenarios for construction are being considered - with and without the inclusion of earthen islands at Arrowhead Marsh. The quantity of islands per tidal marsh are shown under both scenarios in Table 1 and their general locations are shown in Figure 1. The geographic coordinates of island locations are provided in Table 2. Figures 2 and 3 convey the general layout and dimensions of the earthen islands. Figures 4 – 9 show the locations of earthen islands within tidal marshes. Table 1. Earthen Island Quantity by Tidal Marsh

Tidal Marsh Name Number of Earthen Islands to be Installed Scenario 1: Islands

at Arrowhead Marsh Scenario 2: No Islands at Arrowhead Marsh

Arrowhead Marsh 2 0

Bair Island 3 3

Bunker Marsh 2 2

Cogswell B Marsh 3 2

Cogswell C Marsh 3 4

Cooley Landing 1 1

MLK Marsh 2 3

Total 16 16 The earthen islands will be constructed along slough channels primarily using bay mud harvested at the site, however the islands at MLK marsh (and possibly at Arrowhead Marsh) will be built with imported soil. Six pilot earthen islands were constructed in 2012/2013. The 16 islands to be constructed in 2013/2014 will be constructed to similar dimensions and construction will comply with the temporary tidal wetland impact limits and minimization measures in the existing regulatory agency permits for the project. Earthen islands will be constructed using methods that minimize impacts to the surrounding marsh. Earthen island plan view dimensions will be approximately 25 feet (ft) x 10 ft and constructed vertically to a maximum of 3 ft above the existing marsh plain surface. Based on our pre-construction surveys, most islands will be constructed to a maximum height of approximately 2 ft above the existing marsh plain surface. Following construction, islands will be covered with marsh sod salvaged during construction and planted with container plants.



Table 2. Geographic Coordinates of Earthen Island Construction Features

Fill Site Excavation Area Elevation Control Stake Location Latitude Longitude Latitude Longitude Latitude Longitude 1 Arrowhead Marsh #1 37.74449 -122.21470 37.74444 -122.21470 37.74434 -122.21473 1 Arrowhead Marsh #2 37.74285 -122.21365 37.74279 -122.21373 37.74276 -122.21365 Bair Island #2 37.54049 -122.21999 37.54042 -122.21991 37.54043 -122.22011 Bair Island #3 37.53725 -122.21685 37.53716 -122.21676 37.53721 -122.21665 Bair Island #4 37.53793 -122.21427 37.53795 -122.21437 37.53807 -122.21422 Bunker Marsh #1 37.67584 -122.16619 37.67601 -122.16618 37.67592 -122.16632 Bunker Marsh #2 37.67368 -122.16528 37.67359 -122.16525 37.67365 -122.16543 Cogswell Marsh B #1 37.63175 -122.14751 37.63171 -122.14764 37.63181 -122.14767 Cogswell Marsh B #2 37.63243 -122.14292 37.63255 -122.14294 37.63250 -122.14305 Cogswell Marsh B #3 37.63861 -122.14706 37.63871 -122.14700 37.63867 -122.14721 Cogswell Marsh C #1 37.63437 -122.14987 37.63430 -122.14981 37.63441 -122.14972 Cogswell Marsh C #2 37.63171 -122.14926 37.63159 -122.14923 37.63154 -122.14934 Cogswell Marsh C #3 37.63068 -122.15003 37.63052 -122.15020 37.63067 -122.15022 2 Cogswell Marsh C #4 37.63545 -122.15127 37.63556 -122.15139 37.63553 -122.15115 Cooley Landing #2 37.47986 -122.13070 37.47984 -122.13060 37.47993 -122.13058 2 MLK Marsh #2 37.73813 -122.20897 N/A N/A 37.73801 -122.20895 MLK Marsh #3 37.74014 -122.20693 N/A N/A 37.74027 -122.20685 MLK Marsh #4

37.74055 -122.20836 N/A N/A 37.74063 -122.20831

1 Constructed only under Scenario 1: Islands at Arrowhead Marsh 2 Constructed only under Scenario 2: No islands at Arrowhead Marsh

Field Staking of Earthen Island Construction Features and Grade Control H. T. Harvey & Associates (retained by the Conservancy) field staked the earthen island fill location, the adjacent excavation location, and the elevation control stake at earthen island sites. GPS coordinates for the fill, excavation, and control stake locations are provided in Table 2 (above). The fill, excavation, and control stake locations at each site are all within 100 ft of one another. Note that there is no excavation location at MLK Marsh as islands will be constructed with imported fill. Excavation locations were established at Arrowhead Marsh to provide the option to construct with in-situ marsh mud. Elevation control stakes consist of 1.25 inch diameter white PVC posts with the top of post set at Mean Higher High Water (MHHW). Earthen island fill and excavation areas are each marked with a 0.5 inch diameter white PVC post. The crest of each earthen island will be constructed to an elevation of 1.3 ft above MHHW (Figure 3). Elevation control stakes are provided for the Contractor to measure the height of each earthen island and depth of each excavation area to meet the design intent shown in Figures 2 and 3. The specific elevation (in ft NAVD88) of each control stake is provided in Table 3 by marsh location. On the day of construction,



an H. T. Harvey & Associates’ restoration ecologist will flag the footprints of the excavation and earthen island fill areas and point out the location of the elevation control stake at each construction location. Table 3. Control Stake Elevations

Island Location Elevation of Top of Control Stakes (Situated at MHHW) (ft NAVD88)

Arrowhead Marsh #1 6.43

Arrowhead Marsh #2 6.43

Bair Island #2 7.08

Bair Island #3 7.08

Bair Island #4 7.08

Bunker Marsh #1 7.09

Bunker Marsh #2 7.09

Cogswell Marsh B #1 7.22



Cogswell Marsh C #1 7.22



Cogswell Marsh C #4 (backup for Arrowhead) 7.22

Cooley Landing #2 7.05

MLK Marsh #2 (backup for Arrowhead) 6.46

MLK Marsh #3 6.46

MLK Marsh #4 6.46

Earthen Island Construction Materials The earthen islands at Bair Island, Bunker Marsh, Cogswell Marsh, and Cooley Landing (Figures 5, 6, 7, 8) will be constructed using bay mud excavated from a slough channel bank situated within 100 ft of each island. The MLK Marsh islands (Figures 9) will be constructed using imported soil because the substrate at this site is gravelly fill (not bay mud), is not likely suitable to support the target habitat, and is difficult to excavate manually. The Arrowhead Marsh islands will be constructed using either imported soil or bay mud depending upon in-situ bay mud substrate suitability and cost considerations (Figure 4). Soil can be imported to MLK Marsh using a low ground pressure haul truck or similar equipment that will allow existing dense marsh vegetation to recover to pre-construction density in 1-2 growing seasons. Soil can be imported to Arrowhead Marsh by boat/mini-barge to the westward edge of the marsh to within approximately 300 ft of each island construction location (Figure 4). Imported soil must meet the specifications provided in Table 4.



Table 4. Imported Soil Specifications for Earthen Island Construction at MLK Marsh and Arrowhead Marsh

Constituent Minimum Maximum

clay (0 – 0.002 mm) 20% 50%

silt (0.002 – 0.05 mm) 10% 80%

sand (0.05 – 2.0 mm) 30% 80%

organic matter (by weight of soil) 2% 5%

pH 6.4 7.7

boron NA < 3 ppm

Access Site access permissions will be secured by the Conservancy for the Contractor. At Bunker Marsh, Cogswell Marsh, Cooley Landing and MLK Marsh, earthen islands construction locations can be accessed on foot from levees and roads. Construction crews/equipment will require transport via boat to access the Arrowhead Marsh and Bair Island locations. To reach construction locations within marshes, crews must cross marsh slough channels that are up to approximately 20 ft wide.

Construction Work Window Earthen island construction (harvesting of marsh sod, excavation of marsh mud, fill placement, and marsh sod placement) will be done when the excavation and fill areas are not inundated and prior to 1 February 2014. If earthen island construction is not completed in a single day, measures will be employed to prevent the materials from entering tidal waters and to prevent erosion (e.g., tarping the excavated and salvaged materials, removing or securing plywood deployed for marsh protection).

Measures to Protect Marsh during Construction The existing marsh vegetation roots and substrate will be thoroughly protected from damage during island construction. There will be no visible damage to the marsh plain, beyond above ground vegetation compression, outside of the excavation and fill areas following the completion of construction. Protective materials such as plywood sheets over filter fabric (or equivalent) will be installed to completely cover all vegetated marsh areas that will be regularly accessed by workers during island construction, including the access pathways to construction sites and vegetation immediately surrounding the earthen island fill and excavation sites. At MLK Marsh, if a low-pressure haul truck is used to import soil to the fill site, protective material must be placed to protect the marsh in vehicle turn-around areas. These measures are required to prevent damage to marsh vegetation and to prevent the formation of trails to earthen island sites that could be detected and exploited by predators.



Marsh Sod Harvest and Storage At both the earthen island fill and excavation areas, the top 6 vertical inches (0.5 ft) of the existing marsh vegetation, root structure, and sediment (marsh sod) will be salvaged from the surface and stockpiled for planting on the earthen island. If excess harvested sod is available after the earthen island is planted, it will be re-planted in the site’s excavation area. The length and width of each sod piece will be at least 1 ft. Sod should be cut and removed from the fill and excavation areas in large, square pieces with straight edges. This could be accomplished by using flat edged shovels to cut and harvest the sod. Sod will be stockpiled on the adjacent marsh plain in a single layer and handled with care to preserve sod quality for re-use. The underlying marsh vegetation at the sod stockpile site will be protected in a similar manner as the access routes described above. At the direction of an H. T. Harvey & Associates restoration ecologist, up to 10 additional sod pieces will be harvested from surrounding marsh areas (at each island site) to increase marsh plant species diversity on the earthen island.

Excavation Area Earthen islands at Bair Island, Bunker Marsh, Cogswell Marsh and Cooley Landing will be constructed from approximately 11 to 22 cubic yards of bay mud material that will be excavated from an adjacent vegetated slough channel bank. The maximum area of excavation is 250 square ft (ft2) (Figure 2). The maximum allowable depth of the excavation area is 3.3 ft below the top of the control stake (situated at MHHW). This will ensure that post-excavation elevations will be suitable for cordgrass (Spartina foliosa) colonization. No sediment excavation is needed at MLK Marsh which will be constructed using imported fill. Arrowhead Marsh sites will be constructed either from imported fill or excavated bay mud. The existing marsh plain at most excavation areas is typically situated from approximately 0.4 to 1.0 ft below MHHW. Therefore, we anticipate that maximum excavation depths will typically range from approximately 2.3 – 2.9 ft below the existing marsh plain, depending upon the specific site elevations. At the excavation sites, the slough channel segment will be contoured to create a low-elevation bench with 1 H: 1 V side slopes between the unexcavated marsh plain and the excavated low-elevation bench.

Earthen Island Construction Earthen islands will be located along slough channels and will be constructed to form oblong earthen mounds that follow the curve of the adjacent slough channel. The footprint of each earthen island will be 250 ft2. The width and length may vary to fit the specific site conditions. Following sod placement (see below), all earthen islands will be constructed to a height of 1.3 ft above the control stake (situated at MHHW) with 1.5 to 2 H: 1 V side slopes (Figures 2 and 3). Table 5 provides the dimensions (length and width) of the island top and base. Most earthen island fill areas are situated approximately 0.3 ft to 1.0 ft below MHHW. Therefore, it is anticipated that a maximum of 1.6 to 2.3 vertical ft of fill will be required to construct the earthen islands.



The top of the earthen island will be contoured to prevent ponding. The sediment and sod on the top and sides of the island will be lightly compacted to reduce erosion. Sediment and soil should be placed to minimize air pockets in the fill material. The elevation of earthen islands will be verified via measurement (e.g., with a laser level) of the vertical difference between the control stake and top of island. Table 5. Earthen Island Planimetric Construction Dimensions

Total Island Length Including Side Slopes (ft NAVD88)

Total Island Width Including Side Slopes (ft NAVD88)

Length of Island Top At 1ft Above MHHW (ft)

Width of Island Top At 1ft Above MHHW(ft)

25 10 17 2 1 Total island length and width may be adjusted to fit site-specific conditions with the guidance of a restoration ecologist.

Marsh Sod Installation After excavation and earthen island fill, sod will be planted (placed) on the earthen island to completely cover the island. Sod should be fit together tightly to eliminate gaps between individual sod pieces. Where imported soil is used for island construction, the top 6 inches of soil will be wetted to field capacity (with bay water or freshwater) prior to sod placement. All islands will have a finished design elevation of 1.3 ft above MHHW following sod placement. Any remaining sod not needed for the island will be planted back in the excavation area, beginning with the side slopes. When the side slopes are planted, remaining sod should be spread out on the bottom of the excavation area.

Container Plant Installation Marsh gumplant (Grindelia stricta) and saltgrass (Distichlis spicata) will be installed on the earthen islands immediately following marsh sod installation. Gumplant (TreePot4 containers) and saltgrass (1 gallon containers) container stock will be purchased by the Conservancy from The Watershed Nursery (located in Richmond, California). The Contractor will coordinate with the Conservancy and The Watershed Nursery to pick up the container stock from The Watershed Nursery and transport it to the island sites. The portion of each island from 0.2 ft below MHHW (0.2 ft below top of control stake) to the top of the island will then be planted with gumplant on approximate 2.0 ft centers and saltgrass on approximate 2.5 ft centers (Table 6). Planting holes will be cut into the earthen island sod layer such that the container plants fit tightly into the planting holes and surrounding marsh sod is not damaged during installation. Care will be taken to install plants with as much nursery soil around the roots as possible. Plywood or other comparable protective material will be placed on earthen island side slopes to protect sod from damage during planting. Alternatively, marsh gumplant and saltgrass container plants could be installed prior to marsh sod installation, leaving 0.5 ft of the container plant root ball situated above the subgrade soil surface. Marsh sod (0.5 ft thick) would then be immediately installed around the container plants.



Following planting, no air pockets will remain between installed plants, earthen island fill, and marsh sod pieces. Any gaps between marsh sod pieces and/or between sod pieces and container plants will be filled with excess sod such that there are no remaining air pockets following earthen island construction and planting.

Table 6. Container Plant Quantities per Earthen Island (1 gallon containers)

Species Common Name On-Center Spacing (approximate)

Quantity per Earthen Island

Total Quantity (16 islands)

Grindelia stricta gumplant 2.0 ft 50 800

Distichlis spicata saltgrass 2.5 ft 32 512

MLK Marsh

Bair Island

Bunker Marsh

Cogswell Marsh

Cooley Landing

Arrowhead Marsh

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, EsriJapan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2013

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Napa

Oakland

San Jose

StocktonMartinez

Hollister

Fairfield

Santa Cruz

San Rafael

Santa Rosa

Redwood City

San Francisco

SO L A N O

SA N TA C L A R A

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November 2013

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Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX,Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS User Community

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Cogswell Marsh

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CooleyLanding

Figure 4: Arrowhead MarshEarthen IslandConstruction Locations


0 300150 Feet

LEGENDEarthen Island Construction Location

November 2013

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Figure 5: Bair IslandEarthen IslandConstruction Locations


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Cogswell Marsh

MLK Marsh

CooleyLanding

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Figure 6: Bunker MarshEarthen IslandConstruction Locations


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Figure 7: Cogswell MarshEarthen IslandConstruction Locations


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Figure 8: Cooley LandingEarthen IslandConstruction Location


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Figure 9: MLK MarshEarthen IslandConstruction Locations


0 200100 Feet


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Appendix C. Photo-documentation


C-1 H. T. Harvey & Associates 16 April 2015

Appendix C. Photo-documentation

High Tide Refuge Islands for the SFEISP Project Year-2 Monitoring Report C-1 H. T. Harvey & Associates

16 April 2015

Year 1 Islands Bair Island (BAIR 1)

View of the Longitudinal Profile of the Earthen Island in September 2014.

View of the Earthen Island (PP4) in January 2013 (left) and September 2014 (right).

View of the Excavation Area (PP6) in January 2013 (left) and September 2014 (right).


16 April 2015

Belmont Slough North (BELN1)

View of the Longitudinal Profile of the Earthen Island in October 2014.

View of the Earthen Island (PP4) in December 2012 (left) and October 2014 (right).

View of the Excavation Area (PP6) Facing Upstream in December 2012 (left) and Facing Downstream in October 2014 (right).


16 April 2015

Belmont Slough South (BELS1)


View of the Earthen Island (PP4) Facing Downstream in December 2012 (left) and September 2014 (right).

View of the Excavation Area (PP6) Facing Upstream in December 2012 (left) and Downstream and Facing Downstream in September 2014 (right).


16 April 2015

Bird Island (BIRD1)

View of the Longitudinal Profile of the Earthen Island in October 2014.

View of the Earthen Island (PP4) Facing Downstream in January 2013 (left) and October 2014 (right).

View of the Excavation Area (PP6) Facing Downstream in January 2013 (left) and October 2014 (right).


16 April 2015

Cooley Landing (COOL1)

View of the Earthen Island (PP4) in December 2012 (left) and September 2014 (right).

View of the Excavation Area (PP6) in December 2012 (left) and September 2014 (right).


16 April 2015

MLK/ New Marsh (MLK1)

View of Longitudinal Profile of Earthen Island (left) and Close-Up of Vegetation Health (right).

View From the Slough Channel West of the Earthen Island Facing the Earthen Island (PP4) in January 2013 (left) and September 2014 (right).


16 April 2015

Year 2 Islands Arrowhead Marsh (ARH1)

View of the Earthen Island (PP4) in February 2014 (left) and September 2014 (right).

View of the Excavation Area (PP6) in February 2014 (left) and September 2014 (right).


16 April 2015

Arrowhead Marsh (ARH2)


View of the Earthen Island (PP4) in February 2014 (left) and September 2014 (right).

View of the Excavation Area (PP6) in February 2014 (left) and September 2014 (right).


16 April 2015

Bair Island (BAIR2)


View of Earthen Island (PP4) in September 2014.

View of Excavation Area (PP6) in January 2014 (left) and September 2014 (right).


16 April 2015

Bair Island (BAIR3)


View of Earthen Island (PP4) in January 2014 (left) and September 2014 (right).



16 April 2015

Bair Island (BAIR4)





16 April 2015

Bunker Marsh (BUNK1)


View of Earthen Island (PP4) in February 2014 (left) and September 2014 (right).

View of Excavation Area (PP6) in February 2014 (left) and September 2014 (right).


16 April 2015

Bunker Marsh (BUNK2)

View of Earthen Island (PP4) in February 2014 (left) and September 2014 (right).

View of Excavation Area (PP6) in January 2014 2014 (left) and September 2014 (right).


16 April 2015

Cogswell Marsh B (COGB1)

View of Earthen Island (PP4) in January 2014 2014 (left) and September 2014 (right).

View of Excavation Area (PP6) in January 2014 2014 (left) and September 2014 (right).


16 April 2015

Cogswell Marsh (COGB2)





16 April 2015

Cogswell Marsh (COGB3)





16 April 2015

Cogswell Marsh C (COGC1)





16 April 2015

Cogswell Marsh (COGC2)





16 April 2015

Cogswell Marsh (COGC3)




16 April 2015

Cooley Landing (COOL2)




16 April 2015

MLK Marsh (MLK2)




16 April 2015

MLK Marsh (MLK3)




16 April 2015

Documents

High Tide Refuge Islands for the San Project Project # 3415-04€¦ · canopy architecture to provide high and moderate (respectively) forcover rails. Replanting of gumplant will