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US Fish and Wildlife Service - Plum Island and Pilot Island Page i

Underwater Inspection Report

Table of Contents

1. Introduction/Background

2. Method of Investigation

3. Inspection Findings

4. Channel Bottom and Scour Assessment

5. Evaluation and Summary

Appendix A – Photographs ........................................................................................................... A1

Appendix B – CAD Drawings ........................................................................................................ B1

Appendix C – Video Log ............................................................................................................... C1

Disclaimer: The information provided herein is for the limited administrative and operational use of US Fish and Wildlife Service and their contractors. Other requests for this document shall be referred to J.F. Brennan Company, Inc. The accuracy of the information provided is limited by the conditions of the site during the day of the inspection.

US Fish and Wildlife Service - Plum Island and Pilot Island Page 1

1. Introduction/Background

J.F. Brennan Company, Inc. (Brennan) performed an inspection of the Plum Island and Pilot Island structures near Door County, Wisconsin (See ‘Appendix A, Figure 1’). The inspection was conducted to determine the general condition of the in-water structures. These Islands have not been used for some time and the future goals are to open them back up for use. Environmental conditions, such as channel bed material, biological growth, and drift/debris, were also generally noted.

Structure Data

Owner:

Structure:

US Fish and Wildlife Service Plum Island and Pilot Island

Location: Door County, Wisconsin Waterway Crossing: Lake Michigan

2. Method of Investigation

A FHWA Level I visual and tactile inspection of the structure and surrounding riverbed was used to observe signs of distress and deterioration including, but not limited to: movement, cracks, honeycombing, scaling, spalling, exposed reinforcing steel, collision damage, scour, undermining, and piping.

Date of Inspection: August 10, 2021

Brennan Dive Team: Sean McMullen Dive Supervisor Jermain Sykes Inspection Diver Joe Baldoni Standby Diver / Tender

The inspection was conducted using surface-supplied air with equipment including a Kirby Morgan dive helmet with full diver-to-surface communications; and a helmet-mounted Outland Video Camera / Light combo with a video recorder providing live streaming at the dive platform.

All dives were conducted in accordance with Brennan’s Safe Diving Practices Manual as well as all pertinent ADCI, OSHA, and USCG regulations. Additionally, all dives adhered to the dive schedules and decompression tables outlined in the U.S. Navy Dive Manual, Rev. 7.

All measurements referenced hereinafter were approximate and reflect the conditions on-site at the time of the inspection.

The three (3) levels of underwater inspections are described as:

Level I - A simple visual or tactile (by feel) inspection, without the extensive use of tools or measuring devices. It is usually employed to gain an overview of the structure and will precede or verify the need for a more detailed Level II or Level III inspection.

Level II - A detailed inspection which involves physically cleaning or removing growth from portions of the structure. In this way, hidden damage may be detected and assessed for severity. This level is usually performed on at least a portion of a structure, supplementing a Level I.

Level III - A highly detailed inspection of a structure which is warranted if extensive repair or replacement is being considered. This level requires extensive cleaning, detailed measurements, and testing techniques that may be either destructive or non-destructive in nature.

3. Inspection Findings

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US Fish and Wildlife Service - Plum Island and Pilot Island Page 2

• BARR- Plum and Pilot Islands (Click and follow link directly. Your email address must have been given access for you to open up folder. If you do not have access and need it, please reach out so we can get your email address added.)

Plum Island Plum Islands structures were positioned on the Northeast side of the Island. The inspection was broken up into five different structures. These structures included; Boathouse, East Pier, Breakwater, Catwalk, and Ferry Landing (See ‘Appendix A, Figures 2 & 3’).

1. Boathouse: Please see ‘Appendix A, Figures 4 - 8’

1.1 Foundation Type (Diameter, Location and Spacing):

The concrete floor of the Boat House was in overall satisfactory condition (See

‘Appendix A, Figure 9’).

The original diameter of the concrete Piles for the West and East Piles was 39-inches by 35-inches.

The original diameter of the concrete Piles for the North and South Piles was 36-inches by 24-inches.

Bottom substrate consisted of sand, rock, and timber (See ‘Appendix A, Figure

10’).

Please see ‘Appendix B, B2’ for Pile locations and spacings.

1.2 Concrete Pile Condition (Loss and Exposed Rebar):

Overall: All Piles were covered with minor to moderate marine growth and Zebra

Mussels.

**It is important to note that we do not know what condition the concrete Piles were in when they were wrapped with the metal sheeting. I say this because when looking on the South Face at Pile 2, the sheeting had fallen off and where it was once covered was in very poor condition. It also did not appear as though there were any signs of previous repairs.

West Face: Diver worked South to North. Please see ‘Appendix A, Figures 11 - 14’.

• Pile 1: Spalling was observed at the freeze/thaw zone and then at the bottom of the Pile.

o Freeze/Thaw: Went all the way around the Pile and measured 40-inches tall and experienced approximately 1 to 2-inches of loss.

o Near Bottom: Went all the way around the Pile and measured 19-inches tall and 5-inches of loss.

• Pile 2: Was in even worse shape than Pile 1. The rebar cage was completely exposed near the bottom of the Pile and the concrete loss extended well into the Pile, behind the exposed rebar cage.

o The rebar cage measured 29 ½-inches by 17-inches.

• Pile 3: Spalling was observed at the freeze/thaw zone and then at the bottom of the Pile.

o Freeze/Thaw: Minor spalling went all the way around the Pile and measured 51-inches tall and had 1 to 2-inches of loss.

o Near Bottom: Measured 17-inches tall with 5-inches of loss.

• Pile 4: Spalling was observed at the freeze/thaw zone and then at the bottom of the Pile.

o Freeze/Thaw: Minor spalling went all the way around the Pile and measured 20-inches tall and had 1 to 2-inches of loss.

o Near Bottom: Measured 23-inches tall with 7-inches of loss and exposed rebar.

North Face: Diver worked West to East. These Piles were smaller diameter and measured 36-inches by 24-inches. Please see ‘Appendix A, Figures 15 - 18’.

• Pile 1: Was the same Pile from the West Face, Pile 4.

• Pile 2: Spalling was observed at the freeze/thaw zone and then at the bottom of the Pile.

https://jfbrennan.sharepoint.com/:f:/r/sites/DiveInspections/Shared%20Documents/BARR-%20Plum%20and%20Pilot%20Islands?csf=1&web=1&e=pmYtyt

US Fish and Wildlife Service - Plum Island and Pilot Island Page 3 o Freeze/Thaw: Minor spalling went all the way around the Pile and measured 15-inches tall and had 1 to 2-inches of loss.

o Near Bottom: Measured 34-inches tall with 3 ½-inches of loss.

• Pile 3: Was in much better condition than the rest of the inspected Piles.

This Pile was wrapped in metal from top to bottom.

o The metal encasing experienced light to moderate surface rust throughout. It also was starting to separate at the seam.

• Pile 4: Was also wrapped in a metal casing.

o The metal casing experienced light to moderate rust, separation on the seam, and a few small holes.

East Face: Diver worked North to South. Please see ‘Appendix A, Figures 19 - 21’.

• Pile 1: Was the same Pile from the North Face, Pile 4.

• Pile 2: Experienced spalling throughout the entirety of the Pile. At most there was 5-inches of loss with exposed rebar. This was centralized towards the bottom of the Pile.

• Pile 3: On the East side of the Pile the protective metal casing was coming off from the Pile. The seam was completely separated.

• Pile 4: This Pile was also wrapped with the metal casing. It experienced light to moderate surface rust throughout and the seam was starting to separate.

South Face: Diver worked West to East. Please see ‘Appendix A, Figures 22 & 23’.

• Pile 1: Was the same Pile from the West Face, Pile 1.

• Pile 2: At one point in time this Pile was also wrapped in metal, but it has since deteriorated/pulled away from the Pile.

o Spalling was observed near the bottom of the Pile and went all the way around. This area measured 9-inches tall and had up to 8-inches of loss.

• Pile 3: This Pile was also wrapped with the metal casing. However, it was cracking, had holes, and was separating at the seam.

• Pile 4: Was the same Pile from the East Face, Pile 4.

Near the middle of the Boat House there were four more support Piles. These were constructed from concrete and wrapped in corrugated metal. They all appeared to be in satisfactory condition with minor to moderate surface corrosion throughout (See ‘Appendix A, Figure 24’).

• These Corrugated Piles were approximately 2-feet in diameter.

1.3 Boathouse Supports:

These supports were constructed from concrete and ran North to South (See ‘Appendix A, Figure 25’).

They measured 1-foot 4 ½-inches wide.

On the outside Support Beams, it was 24-inches from the Boat House Floor to the bottom of the Support Beam.

On the inside Support Beams, it was 21 ¼-inches from the Boat House Floor to the bottom of the Support Beam Please see ‘Appendix B, B2 - B4’ for Support Beam locations and spacings.

2. East Pier: Please see ‘Appendix A, Figures 26 - 30’.

2.1 Cribbing Condition (Below Water):

Overall, the East Pier was in satisfactory condition throughout. The timbers felt sound throughout. However, they were 100% covered in light to moderate marine growth.

The Pier sat directly on the small rock, sand, and bedrock substrate. The diver could only probe down a few inches into the substrate (See ‘Appendix A, Figures 31 & 32’).

Horizontal and vertical square timbers made up the Pier Cribbing.

• Horizontal: Measured 12-inches by 12-inches and were spaced approximately 12-inches from each other.

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• Vertical: Measured 12-inches by 12-inches.

West Face: Diver worked South to North.

• There was a small section, near the waterline, where the horizontal timber was fractured, it did not appear as though fill loss occurred at this location (See ‘Appendix A, Figure 33’).

• Approximately midway, along the West Face, the water depth was 8-feet.

North Face: Diver worked West to East.

• The second horizontal below the waterline was missing across the entire face. It appeared as though there was minor fill loss at this location (See ‘Appendix A, Figure 34’).

• Approximately midway, along the North Face, the water depth was 10-feet.

West Face: Diver worked North to South.

• Was in overall typical condition, the timber cribbing looked good along with the fill (See ‘Appendix A, Figure 35’).

• Near the Boat Ramp, on the Boathouse, there was a lot more timber debris stacked up.

• Approximately midway, along the West Face, the water depth was 10-feet.

3. Breakwater: Please see ‘Appendix A, Figures 36 - 47’.

3.1 Cribbing Condition (Below Water):

Overall, the Breakwater timbers that made up the Cribbing were in worse condition than the East Pier timber Cribbing. The Breakwater timbers experienced loss and rotted timbers throughout, this was mainly centralized towards the freeze/thaw zone.

There was large riprap placed along the outside of the Breakwater’s Timber Cribbing.

South Face: Diver worked West to East.

• At the waterline, the horizontal timber was missing for the entire width of the South Face. It did appear as though there was fill loss occurring at this location (See ‘Appendix A, Figure 48’).

• Water depth was 5-feet.

East Face: Diver worked South to North.

• Moving from the South Face to the East Face, the timber at the waterline was deteriorated along with the second below waterline.

o Waterline: Measured 11-feet wide and experienced up to 6-inches of loss.

o Second Row: Measured 20-feet wide 8-inches tall and had up to 4-inches of loss (See ‘Appendix A, Figure 49’).

• At the first bend, the water depth was 10-feet.

• Near the same location the above water timber, waterline timber, and the timber directly below the waterline all experienced heavy deterioration.

o Above Waterline: Measured 13-feet wide by 8-inches tall and up to 7-inches of loss.

o Waterline: 22-feet wide by 11-inches tall and had up to 8-inches of loss.

o Below Waterline: 6-feet wide 8-inches tall and had up to 3-inches of loss.

• At the second bend, on the East Face, the timber at the waterline was heavily deteriorated. It measured 15-feet wide by 11-inches tall and had up to 9-inches of loss.

North Face: Diver worked East to West.

• Overall, satisfactory condition (See ‘Appendix A, Figure 50’).

• Water depth was 11-feet.

West Face: Diver worked North to South.

• Moving from the North Face to the West Face, the second timber below the waterline was missing. It was missing for approximately 15-feet.

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• At the first bend there was missing and fractured vertical and horizontal timbers (See ‘Appendix A, Figure 51’).

• Moving South there were missing horizontal timbers with fill starting to come out.

• At the second bend the waterline timber was split.

• Water depth was 10 ½-feet.

4. Catwalk: Please see ‘Appendix A, Figure 52’.

4.1 Concrete Condition (Bedrock):

Overall, the catwalk was in very poor condition. The Piers sat directly on bottom and were not anchored in. Riprap surrounded the base of the Pier.

The Piers were 100% covered with marine growth.

1st Pier: Most Eastern Pier, closest to Boathouse.

• Was listing North.

• In sporadic areas, around the base of the Pier, the diver could stick his hands under the Pier.

o For example, on the South side of the Pier, the undermining measured 9-inches wide by 18-inches tall and 3-inches of loss (See ‘Appendix A, Figure 53’).

2nd Pier:

• Was listing North.

• Undermining and spalling were worst on this Pier.

• North Face:

o Undermining measured: 2-feet 7-inches wide by 18-inches tall and experienced 42-inches of loss.

• East Face:

o Spall measured: 12-inches wide by 36-inches tall and had 4-inches of loss.

o Spall measured: 18-inches wide by 7-inches tall and had up to 7-inches of loss.

• South Face:

o For the complete height of the Pier, spalling exposed the rebar cage. This area measured 2-feet 9-inches wide and had approximately 7-inches of loss (See ‘Appendix A, Figure 54’).

• West Face:

o Spall measured: 4-feet 10-inches wide by 3-feet 6-inches tall and

2-inches of loss.

3rd Pier:

• The construction joint was separated by 3-inches (See ‘Appendix A, Figure 55’).

• North Face:

o Spall: 13-inches wide by 3-feet 6-inches tall and 8-inches of loss.

o Undermining: 1-foot 3-inches wide by 18-inches tall and 6-inches of loss.

4th Pier:

• Similar condition as previous Piers.

5th Pier: Most Western Pier, closest to Breakwater structure.

• Similar condition as previous Piers.

5. Ferry Landing: Please see ‘Appendix A, Figures 56 - 58’.

5.1 Structure Type:

The Ferry Landing appeared to be constructed from poured concrete and small rock wrapped with corrugated steel that went down into the lake bottom.

5.2 Structure Condition:

Overall, the Ferry Landing was in satisfactory condition. There were no signs of holes or any separation to the corrugated sheets.

The structure was 100% covered with light to moderate marine growth.

When the diver wiped away the marine growth, he observed light surface corrosion

US Fish and Wildlife Service - Plum Island and Pilot Island Page 6 throughout (See ‘Appendix A, Figure 59’).

The water depth on the North Face of the structure was 7-feet. The bottom substrate consisted of sand and smaller rock. There did not appear to be any obstructions in the way for the Ferry.

Pilot Island The Dock was on the West side of Pilot Island and was positioned in a Northwest direction (See ‘Appendix A, Figure 60’).

1. Dock: Please see ‘Appendix A, Figure 61’.

1.1 Structure Type:

Steel sheeting surrounded the poured concrete which made up the Dock

Structure. The sheeting was not driven or fastened to the bottom substrate, rather this structure sat directly on the bedrock.

Attached to the concrete cap of the Dock, was a steel Catwalk that was anchored to the cap by four bolts. The Catwalk then went to the Island and was fastened to the bedrock (See ‘Appendix A, Figures 62 - 64’).

1.2 Structure Condition:

Overall: The concrete experienced spalling, scaling, delamination, and efflorescence throughout (See ‘Appendix A, Figures 65 - 70’). Due to these concrete deficiencies a lot of the J Hooks from the sheeting were no longer in contact with the concrete.

East Face: Island Side

• Undermining was observed for the entire width of the Dock. This undermining measured 117-inches wide by 45-inches tall and up to 72-inches deep with exposed rebar.

North Face:

• Undermining was also found throughout the North Face of the Dock

Structure.

o Northeast Corner: The undermining from the East Face continued onto the North Face for 17-inches (See ‘Appendix A, Figure 71’).

o 5-feet from the corner another area of undermining measured 15-inches wide by 14-inches tall and up to 11-inches deep.

o 25-feet from the previous undermining another area was found.

This undermined section measured 20-inches wide by 13-inches tall and up to 9 ½-inches of loss.

West Face:

• Undermining was found on the Northwest corner measuring 36-inches wide by 24-inches tall and 28-inches deep (See ‘Appendix A, Figure 72’).

South Face:

• Approximately 11-feet from the Southwest corner undermining was found measuring 73-inches wide by 14-inches tall and up to 41-inches of loss.

• 7-feet from the previous undermined section another area was found measuring 144-inches wide by 42-inches tall and up to 72-inches deep (See ‘Appendix A, Figure 73’).

1.3 Member’s Size and Orientation:

The dock measured 9-feet 9-inches wide by 38-feet long.

Water depths were taken approximately mid-span on each Face.

• East: 6-feet deep.

• North: 8-feet deep.

• West: 10-feet deep.

• South: 9-feet deep.

1.4 Bedrock:

Bedrock along with large riprap was present at the time of inspection. The J.F.

Brennan team had to dock up on North Face of the Dock as there was large riprap present on the South Face.

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4. Channel Bottom and Scour Assessment

There are only a few times a year that these Islands can be accessed. All of the structures sat directly on the bedrock substrate. In some locations there was also sand and small riprap on top of bedrock. Please see above for water depths at each location.

5. Evaluation and Summary

Plum Island’s Boathouse was considered to be in poor condition. It is our recommendation that the concrete support piles either be replaced and/or repaired. For example, the Piles could be wrapped and then pumped full of concrete to regain its structural integrity.

Plum Island’s East Pier was in satisfactory condition and there were no to minimal repairs needed. None of the repairs would be of urgent need.

Plum Island’s Breakwater Structure was in fair condition. There were some deteriorated timbers that could be replaced but it did not appear as though there was a significant amount of fill loss. The overall integrity of the structure was there but there were definitely localized failures. It is our recommendation that the missing timbers be replaced, and the extremely deteriorated timbers also be replaced.

Plum Island’s Catwalk was in serious condition. We believe that all of these Piers should either be repaired or completely replaced before using as a Catwalk again.

Plum Island’s Ferry Landing was in satisfactory condition. There were no major deficiencies to report. On top of that there did not appear to be any obstructions for the Ferry.

Pilot Islands Dock was in poor condition. The concrete cap experienced spalling, scaling, delamination, map cracking, and efflorescence throughout. Below the waterline the diver found large areas of undermining. Also, on the South Face of the dock there was large riprap present. If someone was unaware of this and tried to moor up to that side of the dock it could cause major damage to their vessel.

Refer to ‘Routine Underwater Condition Assessment Rating Descriptions’ below for explanations of above noted condition rating(s).

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Routine Underwater Condition Assessment Rating Descriptions

Good: No visible or only minor damage was noted. Structural elements may show very minor deterioration, but no overstressing was observed. No repairs are required.

Satisfactory: Limited minor to moderate defects or deterioration are observed, but no overstressing was observed. No repairs are required.

Fair: All primary structural elements are sound, but minor to moderate defects or deterioration was observed.

Localized areas of moderate to advanced deterioration may be present but do not significantly reduce the load-bearing capacity of the structure. Repairs recommended, but the priority of the recommended repairs was low.

Poor: Advanced deterioration or overstressing was observed on widespread portions of the structure but does not significantly reduce the load-bearing capacity of the structure. Repairs may need to be carried out with moderate urgency.

Serious: Advanced deterioration overstressing, or breakage may have significantly affected the load-bearing capacity of primary structural components. Local failures are possible and loading restriction may be necessary. Repairs may be carried out on a high-priority basis with urgency.

Critical: Very advanced deterioration, overstressing or breakage has resulted in localized failure(s) of primary structure components. More widespread failures are possible or likely to occur, and load restriction should be implemented as necessary. Repairs may need to be carried out on a very high priority basis with strong urgency.

We appreciate the opportunity to work with BARR and US Fish and Wildlife Service on this project. If you have any questions or concerns regarding the information in this report or if Brennan can be of any further assistance, please do not hesitate to contact me directly.

Respectfully submitted, Joe Baldoni Dive Division cell 608.799.5952 jbaldoni@jfbrennan.com

J.F. Brennan Company, Inc.

818 Bainbridge Street La Crosse, WI 54603 www.jfbrennan.com http://www.jfbrennan.com/

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Appendix A – Photographs

List of Figures Figure 1 - Plum and Pilot Island, Area Map .................................................................................. A3 Figure 2 - Plum Island, Structure Locations .................................................................................. A3 Figure 3 - Plum Island, Structure Locations .................................................................................. A4 Figure 4 - Boathouse, Overview ................................................................................................... A4 Figure 5 - Boathouse, North Face ................................................................................................ A5 Figure 6 - Boathouse, East Face .................................................................................................. A5 Figure 7 - Boathouse, South Face ................................................................................................ A6 Figure 8 - Boathouse, West Face ................................................................................................. A6 Figure 9 - Concrete Floor, Typical Satisfactory Condition ............................................................. A7 Figure 10 - Bottom Substrate, Small Rock, Timber Debris & Sand ............................................... A7 Figure 11 - West Face Pile 1, Spalling around Base..................................................................... A8 Figure 12 - West Face Pile 2, Exposed Rebar Cage & Heavy Zebra Mussel Coverage ............... A8 Figure 13 - West Face Pile 3, Spalling Around Base .................................................................... A9 Figure 14 - West Face Pile 4, Exposed Rebar .............................................................................. A9 Figure 15 - North Face Pile 2, Spalling Around Base.................................................................. A10 Figure 16 - North Face Pile 3, Metal Sheeting with Minor Separation ......................................... A10 Figure 17 - North Face Pile 4, Hole in Sheeting .......................................................................... A11 Figure 18 - North Face Pile 4, Sheeting Separating at Seam ..................................................... A11 Figure 19 - East Face Pile 2, Heavy Zebra Mussel Coverage & Spalling Throughout................. A12 Figure 20 - East Face Pile 3, Sheeting Separation ..................................................................... A12 Figure 21 - East Face Pile 4, Surface Corrosion on Sheeting ..................................................... A13 Figure 22 - South Face Pile 2, Broken off Sheeting & Spalling Around Base .............................. A13 Figure 23 - South Face Pile 3, Crack in Sheeting ....................................................................... A14 Figure 24 - Middle of Boathouse Corrugated Pipe, Surface Corrosion ....................................... A14 Figure 25 - Boathouse Support Beams, Minor Efflorescence and Map Cracking ........................ A15 Figure 26 - East Pier, Overview .................................................................................................. A15 Figure 27 - East Pier, Overview from North End of Pier .............................................................. A16 Figure 28 - East Pier, East Face ................................................................................................ A16 Figure 29 - East Pier, East Face ................................................................................................ A17 Figure 30 - East Pier, North Face & West Face .......................................................................... A17 Figure 31 - East Pier, Sitting on Bottom Substrate ..................................................................... A18 Figure 32 - East Pier, Sitting on Bottom Substrate ..................................................................... A19 Figure 33 - East Face, Fractured Timber .................................................................................... A20 Figure 34 - North Face, Missing Horizontal Timber .................................................................... A20 Figure 35 - West Face, Typical Cribbing Condition and Rock Fill Above Water .......................... A21 Figure 36 - Breakwater, South Face Missing Horizontal Timber Above Water ............................ A21 Figure 37 - Breakwater, East Face ............................................................................................. A22 Figure 38 - Breakwater, East Face ............................................................................................. A22 Figure 39 - Breakwater, East Face Timber Deterioration Above Water....................................... A23 Figure 40 - Breakwater, East Face Timber Deterioration Above Water....................................... A23 Figure 41 - Breakwater, North Face ........................................................................................... A24 Figure 42 - Breakwater, West Face ............................................................................................ A24 Figure 43 - Breakwater, West Face Timber Deterioration Above Water...................................... A25 Figure 44 - Breakwater, West Face Missing Timber Above Water .............................................. A25

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Figure 45 - Breakwater, West Face Timber Deterioration Above Water...................................... A26 Figure 46 - Breakwater, West Face Timber Deterioration Above Water...................................... A26 Figure 47 - Breakwater, West Face Timber Deterioration Above Water...................................... A27 Figure 48 - South Face, Missing Timber at Waterline ................................................................. A27 Figure 49 - East Face, Deteriorated Timber ............................................................................... A28 Figure 50 - North Face, Typical Condition .................................................................................. A28 Figure 51 - West Face, Deteriorated Vertical and Horizontal Piles ............................................. A29 Figure 52 - Catwalk, Overview ................................................................................................... A29 Figure 53 - Pier 1, Undermining ................................................................................................. A30 Figure 54 - Pier 2, Exposed Rebar Cage .................................................................................... A30 Figure 55 - Pier 3, Construction Joint Separation and Spalling ................................................... A31 Figure 56 - Ferry Landing, Overview .......................................................................................... A31 Figure 57 - Ferry Landing, North Face........................................................................................ A32 Figure 58 - Ferry Landing, West Face ........................................................................................ A32 Figure 59 - North Face, Marine Growth & Surface Corrosion ..................................................... A33 Figure 60 - Pilot Island, Structure Location ................................................................................. A34 Figure 61 - Dock, Overview ........................................................................................................ A35 Figure 62 - Catwalk, Attaching Anchors...................................................................................... A35 Figure 63 - Catwalk, Anchor Points ............................................................................................ A36 Figure 64 - Catwalk, Going to Island .......................................................................................... A36 Figure 65 - Dock Cap, Spalling, Scaling, Delamination, Efflorescence, & Cracks ....................... A37 Figure 66 - Northwest Corner, Spalling....................................................................................... A37 Figure 67 - Southwest Corner, Spalling ...................................................................................... A38 Figure 68 - Dock Cap, Spalling, Scaling, Delamination, Efflorescence, & Cracks ....................... A38 Figure 69 - Northeast Corner, Spalling ....................................................................................... A39 Figure 70 - Southeast Corner, Overpour & Spalling.................................................................... A39 Figure 71 - North Face, Undermining ......................................................................................... A40 Figure 72 - West Face, Undermining .......................................................................................... A40 Figure 73 - South Face, Undermining ......................................................................................... A41

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Figure 1 - Plum and Pilot Island, Area Map

Figure 2 - Plum Island, Structure Locations

N

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Figure 3 - Plum Island, Structure Locations

Figure 4 - Boathouse, Overview

Boathouse

East Pier Breakwater

Catwalk Ferry Landing

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Figure 5 - Boathouse, North Face

Figure 6 - Boathouse, East Face

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Figure 7 - Boathouse, South Face

Figure 8 - Boathouse, West Face

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Figure 9 - Concrete Floor, Typical Satisfactory Condition

Figure 10 - Bottom Substrate, Small Rock, Timber Debris & Sand

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Figure 11 - West Face Pile 1, Spalling around Base

Figure 12 - West Face Pile 2, Exposed Rebar Cage & Heavy Zebra Mussel Coverage

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Figure 13 - West Face Pile 3, Spalling Around Base

Figure 14 - West Face Pile 4, Exposed Rebar

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Figure 15 - North Face Pile 2, Spalling Around Base

Figure 16 - North Face Pile 3, Metal Sheeting with Minor Separation

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Figure 17 - North Face Pile 4, Hole in Sheeting

Figure 18 - North Face Pile 4, Sheeting Separating at Seam

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Figure 19 - East Face Pile 2, Heavy Zebra Mussel Coverage & Spalling Throughout

Figure 20 - East Face Pile 3, Sheeting Separation

Sheeting

Pile