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Hamilton West Harbour Shoreline and Breakwater Class Environmental Assessment: Environmental Study Report

April 17, 2013

Dillon Consulting Limited Page 70

8.0 BREAKWATER IMPROVEMENTS

8.1. Breakwater Alternative Solutions (Class EA Phase 2)

As discussed in Section 4.3.3, a breakwater reduces on-shore wave activity and assists in the reduction of

on-shore flood hazard. Breakwaters also provide protection to boats moored on off-shore docks. The main

basin is the area housing the greatest number of boats and it is the most open to wave action. This section

of the report specifically addresses the breakwater for the main basin.

8.1.1. Breakwater Alternative Solutions

The alternative solutions must primarily address the wave conditions within the basin. The wave

conditions must be reduced to an acceptable standard. A wave height of less than 0.3 m is generally

considered to be an acceptable wave agitation within a marina basin within the boating season.

Breakwaters must also be able to withstand wave and ice conditions at the site.

A “do-nothing” alternative would continue use of the existing breakwater. Floating breakwaters function

by reducing the wave energy that can be transmitted through and under the structure, thus reducing the

wave height on the back (sheltered) side of the breakwater. The design of a floating breakwater is

primarily governed by wave period. Floating breakwater structures become very inefficient when the

design wave period is exceeded. Continued use of the existing breakwater would provide adequate wave

reduction and protection for the existing mooring basin only up to the design wave period. This design

wave period will be exceeded periodically, as it has been in the past. When exceeded, the docks and boats

will be potentially subject to damage, as has occurred in the past. In addition, the length of the existing

breakwater is not sufficient to allow for future expansion of the marina basin, as envisioned under the

Waterfront Concept Plan. Thus, a “do-nothing” option was not considered further.

Alternative solutions to addressing the wave conditions within the main basin were identified and include:

Option 1: Repair Breakwater;

Option 2: New Breakwater – Fixed;

Option 3: New Breakwater –Floating.

Option 1: Repair Existing Breakwater

A review of the previously completed assessments that were carried out by others after the significant

damage to breakwater and docks in the early 1990s concluded that a replacement of the breakwater rather

than a repair is required. Due to the overall physical limitations of the existing structure, it is anticipated

that it cannot be upgraded to provide adequate wave reduction.

Option 2: New Breakwater – Fixed

A new fixed breakwater could be constructed along the outer perimeter of the expanded basin. Fixed

breakwater refers to structures that are placed on the lake bottom and are statically stable. The most

common type of fixed breakwater on the Great Lakes is a stone structure. Other types of fixed breakwater

could include steel sheet pile caisson, crib structures or H Pile with lagging.

Option 3: New Breakwater –Floating

A new floating breakwater can also be constructed along the perimeter of the expanded basin. Preliminary

assessment of wave climate at the location and review of commercially available floating breakwaters

indicates that suitable floating breakwaters exist. The type of breakwater likely to be utilized is a pontoon

type. These are most commonly concrete structures with integrated flotation systems. Pontoon


April 17, 2013


breakwaters can be utilized as walkways or temporary docks. Other types of floating breakwaters can also

be design to provide the required protection.

A floating breakwater can be relocated should future plans for the marina basin size or shape be altered.

The most common type of anchoring system for a floating breakwater for water depths in excess of 10 m is

a concrete block connected to the breakwater with chain or cable. The concrete blocks can readily be

moved.

The interaction of floating breakwaters with ice is difficult to predict and potential for ice damage to a

floating breakwater exists. Potential for ice damage must be assessed based mostly on local experience and

experience of the manufacturer with their particular type of structure and design. Given that an “A” frame

floating breakwater existed at this location for nearly twenty years without notable ice damage suggests

that use of floating breakwater at this site is feasible.

8.1.2. Breakwater Evaluation and Preferred Solution

A detailed evaluation was completed to compare the advantages and disadvantages of each alternative

based on four principal evaluation criteria groups:

Natural environment considerations;

Socio economic and cultural environmental considerations;

Technical considerations; and

Relative cost considerations.

This evaluation if documented in Table 8.1 at the end of this Section and further discussed below based on

the criteria groups noted.

Natural Environment: Both floating breakwater alternatives (Option 1: Repair Existing Breakwater and

Option 3: New Breakwater - Floating) result in minimal impacts to the natural environment. In both cases

work will be required on the anchor system for the floating breakwater however this work is anticipated to

be short term and result in minimal long term disturbance to fish habitat. The fixed breakwater (Option 2)

is placed on the lake bottom and has a greater potential for loss of fish habitat than the floating structure. It

is noted however, that habitat can often be built into the breakwater structure itself. A fixed breakwater

will also impact water circulation within the main basin and water exchange between the main basin and

the Hamilton West Harbour area. The impact on water quality due to the change in circulation pattern

cannot be quantified without detailed modelling. From a natural environment perspective, a floating

breakwater is preferred. There is limited difference in natural environment benefits between Option 1:

Repair Existing Breakwater and Option3: New Breakwater - Floating.

Socio-Economic and Cultural: None of the three alternatives are anticipated to result in negative impacts

on the existing waterfront recreation or commercial facilities, public safety, or cultural heritage.

Regardless of the type of breakwater structure, there is a potential for impact on navigability but all

structures can be designed to minimize impact. From a socio-economic and cultural perspective, all

options are considered similar.

Technical: It is not anticipated that Option 1: Repair Existing Breakwater can result in a structural integrity

that can provide the appropriate level of protection to the main basin. So, from a technical perspective, this

option is least preferred. Considering construction of a new breakwater, a floating structure (Option 3) is

preferred over a fixed structure (Option 2) as it offers greater flexibility for movement to accommodate

changes in the docks within the basin.


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Cost: From a cost perspective, Option 1 – Repair Existing is the lowest cost. Option 2: New Breakwater –

Fixed has the highest cost (approximately $30,000/m) and Option 3 – New Breakwater – Floating has a

moderate cost (approximately $4,000/m). From a cost only perspective Option 1 is preferred.

The preferred option for the main basin breakwater is a new floating breakwater. It offers sufficient level

of protection from wave action with minimal impact on fish habitat and water circulation. It also offers

flexibility to accommodate changes to the docks4 and/or allow for public access and can be constructed for

a moderate cost.

4 The preliminary dock arrangement shown during consultation on this project within the basin is conceptual and was prepared for

the purpose of determining an approximate size of the water area required for the basin and to assist with the general layout and

configuration of the breakwaters. The preliminary dock layout is based on an average boat size of 10 m. The final dock layout will

be determined as the land side configurations are finalized, suitability of dock access points confirmed and operational aspect of the

boating facility confirmed.


April 17, 2013


Table 8.1: Evaluation of Breakwater Types

Evaluation Criteria Option 1: Repair

Existing Breakwater

Option 2: New Fixed

Breakwater

Option 3: New Floating

Breakwater

Natural

Environment

Opportunity to

naturalize the

shoreline and improve

fish habitat.

None of the alternatives

impede the opportunity

to naturalize the


fish habitat.


impede the opportunity to

naturalize the shoreline

and improve fish habitat.


impede the opportunity to

naturalize the shoreline

and improve fish habitat.

Potential for impact to

aquatic or terrestrial

habitat during

construction.

May include some

improvement to the

anchor system but

overall low potential for

impact on existing

habitat expected.

Construction of a fixed

breakwater involves

depositing material on the

lake bottom resulting in

high potential for habitat

impact.

Construction of a new

anchor system but overall

low potential for impact

on existing habitat

expected.

Potential for water

quality improvement.

Involves construction

within the water and has

some potential for

impact to water quality

during construction.

Fixed breakwater

involved long

construction period within

the water and has high

potential for impact to

water quality during

construction.

Fixed breakwater will

impact the water

circulation pattern in the

harbour and has potential

to impact water quality in

the marina.

Involves construction

within the water and has

some potential for impact

to water quality during

construction.

Impact on Erosion. All of the alternatives

provide protection from

wave action and erosion

provided they are

constructed in

conjunction with

appropriate shoreline

treatment.

All of the alternatives



provided they are

constructed in

conjunction with


treatment.

All of the alternatives



provided they are

constructed in

conjunction with


treatment.

Natural Environment

Summary

Both floating breakwater alternatives (repair existing or replace with new

floating breakwater) result in minimal impacts to the natural environment

compared to the fixed breakwater which has the potential to remove fish habitat

and alter water circulation and possibly water quality in the marina.

Socio-Economic and Cultural Environment

Potential for impacts

on waterfront

recreational or

commercial facilities.

All alternatives will

have minimal impact on

existing shoreline and

on-shore facilities.

All alternatives will have

minimal impact on

existing shoreline and on-

shore facilities.

All alternatives will have

minimal impact on

existing shoreline and on-

shore facilities.


April 17, 2013



Existing Breakwater

Option 2: New Fixed

Breakwater


Breakwater

Opportunity for

enhancement of

waterfront recreational

or commercial

facilities/ amenities.

All alternatives involve

improvement to the

protection of the land

and/or water and thus all

provide opportunities

for enhancement of

amenities.


improvement to the



provide opportunities for

enhancement of

amenities. New fixed

breakwater may provide

an opportunity to provide

public access.


improvement to the



provide opportunities for

enhancement of

amenities. New floating

breakwater may provide

an opportunity to provide

public access.

Potential for impact on

public safety.


improvement to the



provide safety

improvement.


improvement to the



provide safety

improvement.


improvement to the



provide safety

improvement.

Potential to impact

cultural heritage

(archaeological

resources or built

heritage and cultural

landscapes) and/or

treaty rights.

Minimal impact on

cultural heritage or

treaty rights.

Minimal impact on

cultural heritage or treaty

rights.

Minimal impact on

cultural heritage or treaty

rights.

Impact on

Navigability.

All alternatives have

potential to impact

navigability. Care will

be taken to design the

breakwater to minimize

potential for negative

impact.


potential to impact

navigability. Care will be

taken to design the



impact.


potential to impact

navigability. Care will be

taken to design the



impact.

Socio-Economic and

Cultural Environment

Summary

All alternatives are similar in their potential for socio-economic and cultural

environment impact. A new breakwater provides the best opportunity for public

access.

Technical

Structural integrity It is not anticipated that

the existing breakwater

can be repaired to

provide adequate

protection for the

marina.

A new breakwater, fixed

or floating can be

designed to provide

structural integrity.


or floating can be

designed to provide

structural integrity.

Level of protection

provided.

It is not anticipated that

the existing breakwater

can be repaired to

provide an appropriate

level of protection.


or floating can be

designed to provide an

appropriate level of

protection.


or floating can be

designed to provide an

appropriate level of

protection.

Design life/

Maintenance

requirements.

This alternative has a

minimal design life.

A new fixed breakwater

has a design life of

approximately 50 years.

A new floating

breakwater has a design

life of approximately 20-

40 years.


April 17, 2013



Existing Breakwater

Option 2: New Fixed

Breakwater


Breakwater

Potential for

contamination issues

Minimal potential to

encounter

contamination issues as

only anchors on the lake

bottom.

Some potential to

encounter contamination

issues due to greater lake-

bottom disturbance.

Minimal potential to

encounter contamination

issues as only anchors on

the lake bottom.

Flexibility A floating breakwater

provides the most

flexibility as it can be

moved to accommodate

changes to the docks.

Additional new

breakwater needed to

accommodate expanded

marina basin.

A fixed breakwater is the

least flexible as the

structure cannot be

moved.

A floating breakwater

provides the most

flexibility as it can be

moved to accommodate

changes to the docks.

Potential impacts on

utilities.

Anchors can easily be

located away from any

utilities.

Cannot be located on top

of any utilities.

Anchors can easily be

located away from any

utilities.

Constructability Relatively easy to

construct.

Relatively easy to

construct.

Relatively easy to

construct.

Technical Summary The new floating breakwater is preferred as it provides more flexibility than a

fixed breakwater and the existing floating structure is not easily upgraded.

Cost

Relative cost

differences.

Lowest Cost. Highest Cost

(approximately $30,000

per m).

Moderate cost

(approximately $4,000

per m).

8.2. Breakwater Alternative Design Concepts (Class EA Phase 3)

Phase 2 of the class environmental assessment considered potential breakwater alternative solutions. The

alternative solutions included repair of the existing breakwater, replacement of the existing floating

breakwater with a new functional floating breakwater or replacement of the floating breakwater with a

fixed breakwater. The process concluded with a new floating breakwater being the preferred alternative

solution option due to a number of environmental advantages and a substantial capital cost advantage.

The alternative design concept stage work included further development of coastal design criteria and

further refinements of construction costs estimates and breakwater layout and configurations.

8.2.1. Coastal Assessment

A coastal assessment was completed including the development of wave climate for the breakwater

location for a full year and for a typical boating season. Boating season is considered to extend from May

15 to September 30. A wave hindcast was completed which looks at wind data from the last 30+ years to

determine the typical wave height, power and period. The winds used in the hindcast were from the

Hamilton Airport and covered a period of August 1971 to December 2011.

The results of the analysis are presented on Figures 8.1 and 8.2. Figure 8.1 indicates the directional

distribution of wave energy and wave heights. Generally, the hindcast shows that the largest winds and

waves in the west harbour come from the northeast with the second largest from the west. The directional

distributions are similar for the full year and the boating season. However, the full year shows a substantial

increase in wave height from the northeast and west quadrants. Figure 8.2 shows the exceedance of wave


April 17, 2013

Dillon Consulting Limited 6

height and wave period for the hindcast period. The wave period was determined as it is a critical factor in

determining the performance a floating breakwater. The figures show that significant waves in the order of

1.2 m in height with a period of 4.1 seconds can be expected to approach the site from the most critical NE

direction during the year. The wave height and period are reduced to approximately 0.8 m and 3.4 seconds

during the boating season.

Wave scatter diagrams and other figures illustrating monthly and annual wave power distribution for full

year and a boating season hindcast are presented in Appendix D.

Figure 8.1: Directional Distribution of Wave Energy and Wave Heights (Full year)

Figure 8.2: Exceedance of Wave Height and Period (Full year)

North NE East SE South SW West NW North

0

5

10

15

20

25

30

35

40

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Wave P

ow

er

(% o

f to

tal)

Wave H

eig

ht

(m)

Wave Height

% Wave Power

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

0.0001

0.001

0.01

0.1

1

10

100

0 0.3 0.6 0.9 1.2 1.5

Excced

an

ce (

%)

Wave Height (m)

wave height

wave period

Wave Period (s)


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8.2.2. Breakwater Design Alternatives

The breakwaters that can function with the local wave environment are expected to fall into two basic

design types. These design types include an “A” frame design and a concrete pontoon design, although

other systems can be also designed for the site conditions.

A-Frame: Figure 8.3 shows an example of an A-

frame breakwater design. An A-frame type

breakwater includes an inverted “A” frame

structure with floats and an underwater frame that

supports a central baffle board that reflects wave

energy. Floats are typically constructed using steel

pipes. The breakwater is secured in its position

with steel chains connected to concrete blocks on

the lake bottom. The breakwater is typically made

up of a number of sections that are connected

together in a straight line to act as one unit. . This

design is the same type as currently used at the site.

However, the main components of the breakwater,

that is the spacing and size of the floats and the size

of the baffle board would need to be properly sized

to function under design conditions.

Concrete Pontoon: Figure 8.4 shows an example of

a concrete pontoon breakwater design. A concrete

pontoon design typically includes a main body of the breakwater which serves as floatation chamber. It is

typically a concrete shell that encloses a foam core. Underwater walls or baffles extend down along the

sides of the caisson. The top of the concrete can be dressed with timber or other products to provide

walking surface and fenders can be attached to the sides of the pontoon to accommodate fair weather

mooring. The breakwater is secured in its position with steel chains connected to concrete blocks on the

lake bottom. The breakwater is typically made up of a number of sections that are connected together in a

straight line to act as one unit.

Figure 8.4: Concrete Pontoon Breakwater

Figure 8.3: A-Frame Breakwater


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Both types of breakwater would be manufactured off-site and likely floated to the site from a remote

location. Both breakwater types have similar anchoring systems consisting of chain connecting it to

concrete blocks on the bottom of the lake.

Using the evaluation criteria developed early in the project, the alternative breakwater types were

evaluated. Table 8.2 at the end of this section shows the comparison for the two breakwater types for each

of the evaluation criteria. The following summarizes the evaluation based on each of the criteria groups.

Natural Environment – The anchoring system for both alternatives is similar and there is limited impact to

the aquatic environment for either alternative. Neither type of floating breakwater will result in a

significant change in water circulation. The existing breakwater occupies approximately the top 3 m of the

water column. The floating systems under consideration are not expected to occupy any greater portion of

the water column.

Socio-Economic and Cultural Environment – Both design types, i.e. “A” frame or concrete pontoon, are

well suited for application at this location. They can be designed to perform well within the wave climate

of the site adequately reduce the waves providing protection for the marina as well as an element of flood

protection for the shoreline features. Neither alternative will impact cultural heritage.

Technical – Both alternatives have a reasonable 20-40 year lifespan and are readily available5. The only

difference between alternatives relates to their ability to provide an opportunity for docking during special

events. The concrete pontoon breakwater can readily provide additional mooring for special events during

light wave conditions. It can potentially also provide pedestrian access if appropriate ramps are provided.

Public access to the main east breakwater would also require appropriate controls in place to restrict access

during times of severe weather. However, no decision regarding pedestrian access to the breakwater has

been made at this point by the City of Hamilton. The evaluation process assumes that no public access is

being provided.

Cost – Costs are expected to be similar, although the “A” frame design has not been manufactured locally

for some time and up-to-date prices from manufacturers are not available. It is anticipated that the cost for

both options would be in the range of $5,500 to $6,500 per metre.

Overall the breakwater types have very similar impacts and both would be appropriate for this location.

Since there is no clear preference between the alternatives, it is recommended that the determination of

breakwater type be based on the market response to minimum performance specifications set by the City of

Hamilton.

During final design, performance specifications should be set out in a document that describes in detail the

functional and physical properties of the breakwater desired. For example, the document would describe

the incident wave conditions the breakwater is expected to operate in with the maximum transmitted wave

conditions permitted. The document would also describe the materials permitted in the manufacture of the

breakwater and applicable standard material specifications, such as CSA or ASTM standards. This

approach is proposed as it allows manufacturers of various proprietary systems to respond to a tender call.

8.2.3. Breakwater Layout Alternatives

Two alternative breakwater entrance configurations were developed. These include a northeast facing

entrance:

5 The approximate lifespan of a floating breakwater as provided by the manufacturer is approximately 25 years. Based on

experiences including the current Hamilton floating breakwater, it can be assumed that with regular maintenance, the lifespan can

extend to 40 years.


April 17, 2013


Option 1: Northeast Facing Breakwater Layout (Figure 8.5) – this option provides protection to

boats entering and exiting from the more frequent but smaller waves from the west; and

Option 2: Northwest Facing Breakwater Layout (Figure 8.6) – this option provides protection to

boats entering and exiting from the less frequent but larger waves from the east.

The configurations were developed to assist in the illustration and assessment of the function and costs of

the design concepts of the breakwaters. Each breakwater layout protects a marina basin designed to

accommodate up to 900 boat slips using a typical boat size of 9 m. The breakwater layouts are conceptual

only, as the final marina design will be undertaken as a separate project.

Both concept designs provide a main entrance 50 m wide. In addition to this wide entrance, access to the

basin can be potentially obtained around the ends of the two main breakwaters. The breakwaters are not

shore connected. Two secondary breakwaters are used in both concepts to control wave penetration through

the main entrance and to control waves diffracting around the tip of Pier 4. The layouts were developed to

provide protection for the ultimate marina size, minimizing breakwater lengths while providing sufficient

channels to allow boats to move properly. The criteria for selection of channel widths and marina entrance

are based on publications produced by the SCHB of the Department of Fisheries and Oceans and the US

Corps. of Engineers6

Figure 8.5: Option 1 – North East Facing Entrance Breakwater Concept

6 Small-Craft Harbor: Design, Construction and Operation, J. W. Dunham and A. A. Finn, Special Report No. 2, U.S. Army Corps.

Of Engineers, Coastal Engineering Research Center, December 1974. Planning Guidelines for Recreational Harbours in Ontario,

Small Craft Branch, Department of Fisheries and Oceans, prepared by Hough Stansbury, Woodland Limited, 1992.


April 17, 2013


Figure 8.6: Option 2 – North West Facing Entrance Breakwater Concept

Using the evaluation criteria developed early in the project, the alternative breakwater layouts were

evaluated. Table 8.3 at the end of this section shows the comparison for the two breakwater layouts for

each of the evaluation criteria. The following summarizes the evaluation based on each of the criteria

groups.

Natural Environment – The layout of the breakwater will have no impact on the natural environment.

Socio-Economic and Cultural Environment – Both layouts provide adequate protection for the marina.

During the consultation process with stakeholders the boaters expressed a slight preference for the west

facing entrance.

Technical – There is no technical difference between the layout alternatives.

Cost – There is no cost difference between the layout alternatives.

Overall the differences between the layout alternatives relate solely to the type and frequency of wave they

protect against for boaters entering or leaving the basin. As noted above, during consultation boaters

indicated a slight preference for a west facing entrance so that there is protection from the less frequent but

larger waves coming from the east. Thus, overall Option 2: the northwest facing entrance is preferred.

It is noted that the layout concepts shown on Figures 8.5 and 8.6 were prepared for the ultimate marina

size. In reality, the size and operations of the marina will evolve over many years. Although the maximum

size is based on a market study incorporated in the Phase 1 Technical Report (Appendix A), it may take

many years before this capacity is achieved. If the breakwater is installed to far from the docks there is


April 17, 2013


potential for waves to be generated in the space between the docks and the breakwater. An assessment of

potential wave generation between the breakwater location and moored boats was undertaken to determine

the amount of open water that could exist between the docks and marina at this location. The results of this

assessment indicate that at the time of installation there should be no more than 100 meters of open water

between the breakwater and the floating docks.

To determine the final breakwater layout and location, the number of docks and approximate configuration

must be confirmed. It is recommended that a final decision regarding the location of the breakwaters

should be made at the time of final design and contract award.

Installation of the new floating breakwater will require approval of the Hamilton Port Authority. Other

agencies, such as the department of Fisheries and Oceans and Hamilton Conservation Authority should be

advised of the work. Their approvals may be required.


April 17, 2013


Table 8.2: Evaluation of Breakwater Design

Evaluation Criteria Option 1: A-Frame Option 2: Concrete Pontoon

Natural

Environment

Opportunity to

naturalize the


fish habitat.

No difference – neither alternative significantly

changes shoreline or fish habitat.

No difference – neither alternative

significantly changes shoreline or fish

habitat.



habitat during

construction.

No difference – both alternatives have the

minimal impact on fish habitat as a result of the

anchoring system and no impact on terrestrial

habitat.

No difference – both alternatives have

the minimal impact on fish habitat as

a result of the anchoring system and

no impact on terrestrial habitat.

Potential for water


No difference – both alternatives provide

adequate water circulation.

No difference – both alternatives

provide adequate water circulation.

Impact on Erosion. No difference – both alternatives will assist in

the reduction of on shore flooding and erosion

potential.

No difference – both alternatives will

assist in the reduction of on shore

flooding and erosion potential.

Natural Environment

Summary

Both alternatives will assist in reducing on-shore wave action and flooding and thus

erosion and neither will have a significant impact on fish habitat or terrestrial habitat.



on waterfront

recreational or


No difference – both alternatives will protect

recreation and commercial facilities.


protect recreation and commercial

facilities.

Opportunity for

enhancement of


or commercial


Both alternatives will protect recreation and


Both alternatives will protect



public safety.





facilities.

Potential to impact

cultural heritage

(archaeological

resources or built


landscapes) and/or

treaty rights.

No difference – neither alternative will impact

cultural heritage.


will impact cultural heritage.

Impact on

Navigability


protection during storms and require navigable

waters protection act approval.


provide protection during storms and

require navigable waters protection

act approval.

Socio-Economic and


Summary

Both alternatives will protect the amenities at the waterfront.

Technical

Structural integrity No difference – both are suitable for site

conditions.

No difference – both are suitable for

site conditions.


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Evaluation Criteria Option 1: A-Frame Option 2: Concrete Pontoon

Level of protection

provided.

No difference – both are suitable for site

conditions.

No difference – both are suitable for

site conditions.

Design life/

Maintenance

requirements.

No difference – both have a life of 20-40 years

and require the same maintenance.

No difference – both have a life of

20-40 years and require the same

maintenance.

Potential for

contamination issues.

No difference – both are in the same location

and contamination issues are not anticipated.

No difference – both are in the same

location and contamination issues are

not anticipated.

Flexibility Less suitable for boat docking but can be

modified for boat docking at an extra cost.

More suitable for boat docking.


utilities

No difference – neither alternative is likely to

impact utilities.

No difference – neither alternative is

likely to impact utilities.

Constructability No difference – both are straightforward to

construct.

No difference – both are

straightforward to construct.

Technical Summary Both alternatives have a reasonable design life and provide the same level of

protection. The Concrete breakwater provides a more suitable opportunity for

temporary boat docking should that be desirable.

Cost

Relative cost

differences.

Capital costs are similar for both alternatives

(approximately $4,000 per metre). Operation

and maintenance costs would also be similar for

both alternatives.

(Note: Budget pricing estimates presented in this

document are based on information supplied by the

manufacturer, SF Marine)

Capital costs are similar for both

alternatives (approximately $4,000

per metre). Operation and

maintenance costs would also be

similar for both alternatives.

(Note: Budget pricing estimates presented in

this document are based on information

supplied by the manufacturer, SF Marine)


April 17, 2013


Table 8.3: Evaluation of Breakwater Layout

Evaluation Criteria Option 1: North-East Facing Entrance Option 2: North-West Facing

Entrance

Natural

Environment

Opportunity to

naturalize the


fish habitat.

No difference – neither alternative significantly

changes shoreline or fish habitat.


significantly changes shoreline or

fish habitat.



habitat during

construction.

No difference – both alternatives have the

minimal impact on fish habitat as a result of the

anchoring system and no impact on terrestrial

habitat.

No difference – both

alternatives have the minimal

impact on fish habitat as a

result of the anchoring system

and no impact on terrestrial

habitat.

Potential for water



adequate water circulation.


provide adequate water circulation.

Impact on Erosion. No difference – both alternatives will assist in

the reduction of on shore flooding and erosion

potential.


will assist in the reduction of on

shore flooding and erosion

potential.

Natural Environment

Summary

There is no difference between these alternatives from a natural environment

perspective.



on waterfront

recreational or





will protect recreation and


Opportunity for

enhancement of


or commercial


Both alternatives will protect recreation and

commercial facilities. The north-east facing

entrance layout will provide the best protection

against the smaller more frequent waves.

Both alternatives will protect

recreation and commercial

facilities. The north-west facing

entrance layout will provide the

best protection against the larger

although less frequent waves.

During consultation, boaters

expressed a slight preference for

this alternative.


public safety.



No difference – both options will


facilities.

Potential to impact

cultural heritage

(archaeological

resources or built


landscapes) and/or

treaty rights.

No difference – neither option will impact

cultural heritage.

No difference – neither option will

impact cultural heritage.


April 17, 2013


Evaluation Criteria Option 1: North-East Facing Entrance Option 2: North-West Facing

Entrance

Impact on

Navigability

No difference – both options provide protection

during storms and require navigable waters

protection act approval.

No difference – both options

provide protection during storms

and require navigable waters

protection act approval.

Socio-Economic and


Summary

Both options with protect the waterfront amenities. A slight preference for the

north-west facing entrance was expressed by representatives of some of the boating

organizations.

Technical

Structural integrity No difference – both are suitable for site

conditions.

No difference – both are suitable

for site conditions.

Level of protection

provided.

No difference – both are suitable for site

conditions.

No difference – both are suitable

for site conditions.

Design life/

Maintenance

requirements.

No difference – both have a life of 20-40 years

and require the same maintenance.

No difference – both have a life of

20-40 years and require the same

maintenance

Potential for

contamination issues

No difference – both are in the same location

and contamination issues are not anticipated.

No difference – both are in the

same location and contamination

issues are not anticipated.

Flexibility No difference – both provide similar flexibility. No difference – both provide

similar flexibility.


utilities

No difference – neither option is likely to

impact utilities.

No difference – neither option is

likely to impact utilities.

Constructability No difference – both are straightforward to

construct.

No difference – both are

straightforward to construct.

Technical Summary There is no difference between the layout options from a technical perspective.

Cost

Relative cost

differences.

No difference – cost is the same for both

options.

No difference – cost is the same for

both options.

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