Managing Coastal Resources

8/21/2019 Managing Coastal Resources

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Managing Coastal

ResourcesResources and the EnvironmentJessica Coote - 27 March 2015

MANAGING COASTAL RESOURCES - JESSICA COOTE 1

(Apple Images, 2014)


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1.0 Introduction

1.1 Aim of Report

With tourism contributing 4.5 Billion Australian Dollars per annum to the Gold

Coast City Council, sustaining the aesthetic beauty of the coastline has become a key

aspect of sustaining Gold Coast beaches (Mullins, 2015). However, beach and sea

processes are having a detrimental effect on any attempt to pursue greater opportunities

in the tourism industry. As part of the Ocean Beaches Strategy, the City of the Gold Coast

is developing the Palm Beach Shoreline Project- this comprehensive strategy aims to

provide permanent protection of the the foreshore at Palm Beach.

The project aims to:

-reduce the vulnerability of the beach and beachfront development to storm damage

-protect, and if practical, enhance the beach amenity for the community

-provide a sustainable, cost effective and integrated solution

-avoid or mitigate adverse environmental and social impacts.

The aim of this report is to investigate the effectiveness of the strategy of Beachreplenishment stabilised by a continuous seawall in achieving the first aim of the Palm

Beach Shoreline Project. This will be done by analysing fieldwork data collected at Palm

Beach and discussing the impact of coastal processes and their management strategies,

then evaluating two management strategies (including the strategy of beach

replenishment stabilised by a continuous seawall).


Figure 1 GROYNE AT PALM BEACH

(Fieldwork photo, 2015)


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1.2 Location

Palm Beach is an iconic part of the Gold Coast Shoreline. The 3.8 kilometre stretch of

beach located on the southern Gold Coast, is an iconic part of the East Australian Coast,

but is susceptible to extreme beach erosion. A popular tourist destination, Palm Beach is

located between Tallebudgera and Currumbin Creek, and

85 kms South of Brisbane (The University of Queensland,

2015). Figure 1 depicts the location of Palm Beach. A

beachside suburb, many residences have been built directly

on the dune system, mainly on the fore dune. Therefore

these houses are susceptible to erosion by waves and other

coastal processes (The University of Queensland, 2015).

Cyclone Barbara of 1967 was detrimental to Palm Beach,

with waves thrashing the coastline and eroding up to the

front line of houses.

The following table provides the approximate number of residents in Palm Beach

from 1954 to 2011. It is clear from the evidence that the population has continued to rise

steadily, with a dramatic increase from 1961 to 1986, and a small dip in the Palm Beach

population in 2006. The great increase in the 1960-80’s period saw many residents move

closer to the coastline- this dramatically increased the amount of property at risk oferosion and storm damage. It is important to note that even with a string of Tropical

cyclones occurring in 1967, this did not deter new residents or where they built.

Palm Beach's census populations have been:

(QLD Places)

Census Year Population

1954 660

1961 1491

1986 12,552

2001 13,943

2006 13,494

2011 13,956


Figure 2

(Google Images)

MAP OF PALM BEACH


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1.3 Data Collection

Fieldwork was conduced on Friday 27th February 2015 at Palm and Kirra Beach on the

Gold Coast, and an additional trip to Point Danger to observe the sand by-pass system.Whilst at the field locations, the following factors were observed and assessed:• Land Use• Physical Features• Protection Factor• Evidence of Storm Damage• Waves- frequency, estimated length, estimated height and direction.• Human management evident• Width and Angle of the beach• Wind

Some of the numbers involved in the investigation are estimated because limitedresources did not allow for exact calculations to be achieved. A clinometer, compass andstopwatch were used. Another limitation to the accuracy of the report is that fact thatmeasurements were only taken during one time period, therefore the beach conditions

could be altered by the time of day, season and local interference from weather. For a moresound justification and assessment of conditions,a longer research and fieldwork periodwould be needed.



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Table of Contents

Managing Coastal Resources 1

Resources and the Environment 1 1.0 Introduction 2

1.1 Aim of Report 2

1.2 Location 3

1.3 Data Collection 4

Table of Contents 5

List of Figures 6

2.0 Analysis 6

2.1 Coastal Processes Evident 7

2.2 Human Processes 7

2.3 Impact of Storm Damage 8

2.4 Identification of Management Strategies 10

3.0 Decision Making 13

3.1 Evaluation of Beach Replenishment stabilised by a continuous seawall 13

3.2 Evaluation of an Artificial Reef 14

4.0 Conclusion 15

4.1 Recommendation 16

4.2 Justification 16

4.3 List of References 16



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List of Figures

Figure 1 Gryone at Palm Beach (Fieldwork Photo,2015)Figure 2 Map of Palm Beach (Google Images,2015)Figure 3 Erosion near Palm Beach Houses (Fieldwork Photo,2015)Figure 4 Transect of Palm Beach (Fieldwork Sketch,2015)

Figure 5 Cyclone Dinah (BOM, 2013)Figure 6 Palm Beach 1967 (Australian Government, 2001)Figure 7 Florida Management (USA Geological Survey, 2000)Figure 8 Table of Management Strategies (Fieldwork Data,2015)

Figure 9 Sand By-pass (Fieldwork Photo,2015)Figure 10 Diagram of a Constructive Wave (Worldyword,2011)

2.0 Analysis



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2.1 Coastal Processes Evident

Intense low pressure systems off the coast generate large waves and elevated water levels;

these exacerbate natural processes such as erosion, transportation and deposition. Erosion,defined as the destructive wearing away of the coastline, is particularly enhanced by large

waves(Skinner, Redfern, & Farmer, 2014). The power of the waves thrashing against acoastline causes weaknesses in the rock to widen- this is called Hydraulic Action.However there are other types of coastal erosion, including corrasion, corrosion andattrition (Easton, Leahy, Ramsdale, & Ward, 2010). Eventually sediment is deposited intothe water and transported down the coastline

by longshore drift (Easton, Leahy, Ramsdale, &Ward, 2010). Created by winds, wave and tidalenergy, longshore drift is the movement of sand

along the coastline, when the direction the sandmoves in depends on the dominant wavedirection (Coastal Watch, 2008). Longshoredrift can be interrupted by human intervention

and management strategies such as groyens-walls, often wooden, built at right angles to the

beach to interfere with the longshore drift andtrap sand to build up a beach. An example of a

groyen was seen during fieldwork at PalmBeach.

Exacerbation of coastal processes can causestorm damage to residences and humanstructures along the coastline. The local dunesystem is also an important feature of Palm

Beach, this having a great impact on the level of protection already offeredenvironmentally. Residents have built on the fore-dunes, the second weakest dune in theformation, therefore the protection is minimal to the houses behind. This can be directly

above in Figure 3.

2.2 Human Processes

Human actions clearly exacerbate storm damage. An example at Palm Beach is how closehouses have been built to the beach. The pressure of structures on the fore dunes destroys

the dunes underneath, therefore disrupting the system of the beach. Building so close tothe shoreline also disrupts local ecosystems and habitats along the coast. Figure 3captured during fieldwork was taken facing North North West; it demonstrates thedramatic erosion along the coastline and how close it is the Palm Beach houses.


EROSION NEAR PALM BEACH HOUSESFigure 3

(Fieldwork photo,2015)


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At Palm Beach the following information was used to create a transect of the beach:• The distance from the back of the beach to the foreshore was 42 metres.• The direction of the waves on the date of fieldwork was West South West. Therefore the

prevailing wind was of a South West direction during fieldwork.• Using a clinometer, the angle of the slope of the beach is -6 degrees.

As demonstrated in the above transect, there is clear evidence of erosion along the

coastline. This shows clearly the immediate risk Palm Beach is of greater storm damagewhich, by turn, threatens the Gold Coast.

2.3 Impact of Storm Damage


(Fieldwork photo)

Figure 4 TRANSECT OF PALM BEACH


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Storm damage on Palm Beach has resulted in severe erosion on the foreshore, destroyinghouses along the front part of the beach. Fieldwork photographs shows evidence oferosion on the front line of the houses on Palm Beach.

Economically, storm damage can cost residents and local councils millions of dollars of

repair. Cyclone Dinah of 1967 culminated an estimatedtotal financial cost of $250 Million at todays rate (W,2002). Severe erosion impacted houses and businessesalong the Queensland Coast

Environmentally, coastal processes can sometimes leadto unusual effects- for example during TC Dinah (1967)the high water mark rose to 10 m above normal levels

(Australian Government: Bureau of Meteorology, 2015).This clearly then led to infrastructure being damaged oreven destroyed- the esplanade at Surfers Paradise on theGold Coast collapsed from the impact of large waves

(Callaghan, n.d.). Banana and cane crops were wipedout on the Tweed Coast as a result of TC Dinah, this

thus affecting locals lively-hoods and income.

Socially, beaches provide an area of recreation and aesthetic beauty. Images of white sandand crystal oceans are replaced by rubbish, plants and general detritus piled on thecoastline after storms. In 1967, several severe tropical cyclones collided with the Gold

Coast shoreline- including TC Dinah, Barbara, Dulcie, Elaine and Glenda. 8 million cubicmetres of sand was eroded from the beaches and threatened the backing Gold Coastroads, houses and hotels (Coastal watch, 2008).The cyclones of 1967 did bring home topeople the vulnerability of this coast unless some measures were taken to improve what

was here in the way of protection and development (Coast, 2013). Generally mostresidents have a positive attitude towards the protection of beaches and coasts in theirimmediate area. Citizens of the Gold Coast have a

good understanding of coastal processes- inparticular erosion and the effect it may/does

have- however some are unwilling to providetheir own services and money to help protect the

beaches; they view it as a ‘force of nature’ thatshould not be stopped.Because many residences and local businesses aresituated on the front line of the beach, this has

created an enhanced environment for erosion tooccur.

In relation to the immediate threat to Palm Beach,storm damage has had a great impact on the houses and beaches of the southern Gold


CYCLONE DINAHFigure 5

Figure 6 PALM BEACH 1967

(BOM,2015)

(BOM, 2013)


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Coast. Shown in Figure 5, Palm Beach suffered severe erosion during the tropical cyclonesof 1967. This coastal damage has been encouraged by ongoing recreational use and thegrowing population of coastal apartments and residences along the Palm Beach coastline.

2.4 Identification of Management Strategies

There are various management strategies that countriessuffering sever storm damage put in place. The GoldCoast- a coastal resort city whose urban environment has

evolved through a series of human interventions on the

natural shoreline, is reliant on a perceived high qualityenvironment which in turn is reliant on continuing

maintenance (Cooper, J.A.G., 2012). There are currentlyseveral management strategies in place on the GoldCoast in an attempt to cope with the impact of coastalprocesses. All beaches located on the Gold Coast are

currently under some sort of management plan (Mullins,2015). Figure 7 highlights the dramatic change along anAmerican Coastal state (Florida) after various

management strategies were placed in practise to combatseveral erosion.

After the cyclones of 1967, an assessment of Gold Coast

beaches known as the Delft Report of 1970 was created toguide coastal management on the Gold Coast for over 30years. The report, which remains highly influential in themanagement of the coastline to this day, recommended

an extensive sand nourishment regime across all beaches,as well as highlighting the importance of dune formation through these nourishmentworks, and shielding them from wind erosion with native vegetation and sand-catching

fences (Gourlay,1996).

The operations of dredging on the Tallebudgera and Currumbin creeks and theconstruction of rock groynes and seawalls was also under taken as a result of the Delft

Report. An option which has not been implemented at Palm Beach but one that could beextremely beneficial is the implementation of an artificial reef. Created with man-madematerials, artificial reefs increase habitat available for marine life, and enhance

recreational amenities (Griffith Univsity, 2005) . A reef as been implemented at

Narrowneck, North of Palm Beach, with great success.


Figure 7

(USA Geological Survey, 2000)

FLORIDA MANAGEMENT


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In terms of Palm Beach specifically, the local council has had a mixed response in regardsto the idea of a seawall and sand replenishment on their beach- some arguing that the wall

will provide great and successful protection to the front line of houses- others arguing thatit will destroy the local and relaxed nature of the healthy beach environment.

Figure 8 TABLE OF MANAGEMENT STRATEGIES ON THE GOLD COAST



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Many experts suggest that the beaches of the Gold Coast are the basis of the Tourist

industry, and that is a good enough reason for councils to continue preserving, managingand maintaining them. Adopted in 2010, the Gold Coast Shoreline Management Plan(GCSMP) identified Palm Beach as requiring priority action to protect local public andprivate infrastructure from storm surge and erosion (Australian tenders). In late 2014 it

was decided that the Plan would adopt the strategy of ‘Beach Replenishment stabilised bya continuous seawall.’ This plan will be evaluated in Section 3.1.

Management strategy What is it Example on the Gold

Coast

Other Information

Groynes Groynes are walls, oftenwooden, built at rightangles to the beach tointerfere with the

longshore drift an trapsand, building up the beach.

Two groynes have beenconstructed-one at KirraBeach and another atMiles Street

( QueenslandGovernment, n.d.).

Sea Wall Typically concretestructures, sea walls are built at the back of beaches to offerprotection from largewaves.

Construction of a seawall at Broadbeach began in February 2015(QueenslandGovernment, 2015).

This sea wall will cost$1.5 million, andconstruction willcontinue for six months.

Artificial Reef An artificial reed is aman-made structure, built to promote marinelife , control erosion orimprove surfing.

An artificial reef wasconstructed atNarrowneck in 1999 and2000 (QueenslandGovernment, 2015).

At a total length of 450m,the reef was made out ofPrefabricated geo-textile bags with a total cost ofapproximately $2.5million.

Beach Nourishment Beach nourishmentinvolves moving sandfrom one location to

another to create a largervolume of sand to bemoved during storms,therefore protectingproperty behind the beach.

Projects have beenundertaken all alongGold Coast beaches-

including a 5 km stretch between Surfers Paradiseand Main Beach. A sand- bypass has beendeveloped at Pointdanger on the QLD/NSW boarder (WaterResearch Laboratory,n.d.).

As a result, the width ofthe beach has increasedfrom June to Decemberof 2013, as seen in the

image below.

An diagram of the sand bypass at Point Danger.



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3.0 Decision Making

The following section will outline two optionsthat should be considered in tackling the issue of

erosion at Palm Beach on the Gold Coast; the firstthe prospect of Beach Replenishment stabilised by a continuous seawall, the second, an artificial

reef. The two solutions will be judged againstfour criterion: reducing the vulnerability of the

beach to storm damage, cost effectiveness,minimal environmental impacts and positive

social value.

3.1 Evaluation of Beach Replenishment

stabilised by a continuous seawall

As the original plan for the Palm Beach Shorelineproject, the solution of constructing a sea wall in addition to beach replenishment is a

viable option. Offering protection to infrastructure along the coastline and thoseresidences susceptible to immediate effects of erosion and beach processes- a sea wallwould be a successful solution. In terms of reducing the vulnerability of the beach tostorm damage, the wall would only be a last-line of defence to the houses behind the

beach. However in addition to the wall, beach replenishment would widen the width of

the beach, therefore encouraging dune formation and creating a greater distance betweenthe berm (the high water mark) and the dune climax at the back of the beach. This

solution is not viable in terms of cost effectiveness- the English Environment Agency(2007), gives an average construction cost for seawalls of US$2.65 million/AUD $3.37million (at 2009 price levels). This includes all initial construction, however it does excludemaintenance expenses- which is a flaw in the solution. The aspect of beach replenishment

would then add to the overall finical cost of the plan-the minimum expenditure is usually$1 - $2 million dollars; larger, longer-lasting projects often cost much more (e.g., $100million - 1 billion)(brynmawr, n.d.). Environmentally, this plan is somewhat positive and

somewhat negative- a concrete wall on the beach may have some lasting effects of theenvironment, such as concrete spilling in the natural habitat. Whilst additional sand onthe shoreline would promote and encourage dunes and sustain the environment. Finally,the social value of the wall would be aesthetically unpleasing to the eye- potentially

ruining the “beach-feel” and look of the Gold Coast.The sand replenishment however would allow for more social activities and enjoyment onthe beach. Sand replenishment can be developed in a variety of ways, including a sand

by-pass system, which has been implemented at Danger Point on the Queensland and

New South Wales coastal border- this can be seen in Figure 9. Although this system haspromoted sand replenishment at Kirra Beach, it is unlikely this system would worksufficiently at Palm Beach.


SAND BY-PASS

(Fieldwork photo)

Figure 9


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3.2 Evaluation of an Artificial Reef

An alternate solution to protecting Palm Beach, instead of Beach replenishment stabilised by a continuous seawall, is to create an artificial reef just off the coast of the beach. As

stated by the Scottish Natural Heritage Organisation in 1998 reefs act as a buffer, anddissipate part of the incident wave energy before it reaches the dune face, protecting theupper beach from erosion and encouraging deposition (Scottish Natural Heritage, 1998).An example of a reef was initiated as part of the North Gold Coast Beach Protection

Strategy at Narrowneck, its primary purpose towiden and protect the northern Gold Coast

beach from erosion in storm conditions. In

terms of the first criterion, to reduce thevulnerability of the beach from storm damage,an artificial reef would not be successfulinitially. However, after time the beach would

be expanded as less destructive waves woulddrain away the sand from the beach, thereforethe overall erosion of Palm Beach woulddecrease. If the reef was constructed with

similar products (Prefabricated geo-textile

bags) and over the same dimensions, theestimated coast would be approximately $2.5

million Australian Dollars. However there is little to no maintenance cost involved in theartificial reef, and therefore this cost would be the total expenditure. Environmentally,natural processes are only partly disrupted by the implementation of an artificial reef,allowing dunes to stabilise on the shore. Thus, this creates a more sound habitat for

environmental and coastal processes.

Because an artificial reef is constructed out of geo-textile fabric, a permeable fabric which

is commonly used to separate, filter, reinforce, protect or drain soil, it is consideredenvironmentally friendly, therefore having little environmentally impact. Socially, the biggest impact this solution would have on the surrounding communities would be theimpact on the surf break and the fact it may disrupt amenity use of Palm Beach. However,

in most cases artificial reefs have be known to create a better surf break and surfingenvironment. Narrowneck is an example of the improvement of surfing conditions due tothe artificial reef. The addition of beach replenishment to this strategy is possible andfeasible; however it has not, in this report, been considered in the evaluation.Artificial

reefs have many positive aspects- and at Palm Beach the most prominent example of thisis how environmentally friendly it would be to the coastline of the Gold Coast. Extensivedigital imagery, hydrographic survey and observational monitoring shows that the reef


(Worldyword,2011)

DIAGRAM OF A CONSTRUCTIVE WAVEFigure 10


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implemented at Narrowneck on the Gold Coast was a successful project in terms of bothwidening the beach (by 40metres over a decade) and reducing the power and impact ofharsh waves. Promoting a clearer break of the waves would, as stated above, encourage

more constructive waves rather than destructive ones; consequently building up the beachwith sediment. The lack of maintenance needed is also a largely positive aspect. Although

economically compared to the first solution of a sea wall and beach replenishment theyare quite similar, the first stated possible solution requires constant preservation andconservation for it to protect the beach to its fullest potential. The level of protection thereef would offer Palm Beach would take years to be demonstrated and it would therefore

be unclear to measure an immediate success rate. This, of course, is one of the main

negatives of the solution for an artificial reef; another negative being that initially andduring the construction process, the surfing capabilities of the beach would be disrupted-this possibly causing distress to the local Gold Coast surfing community of Palm Beach.

4.0 Conclusion



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In conclusion, Palm Beach requires priority action to protect local public and privateinfrastructure from storm surge and erosion.

4.1 Recommendation

The original strategy of ‘Beach replenishment stabilised by a continuous seawall’ is not, infact, the right strategy to implement. The alternative solution of implementing an artificialreef off the coast of Palm Beach satisfies the chosen criteria to a higher standard, and itwould therefore be logical to implement this strategy instead. In terms of better achieving

the first aim of the Palm Beach Shoreline Project- to reduce the vulnerability of the beachand beachfront development to storm damage, an artificial reef would work best.

4.2 Justification

The conservation of local beach communities on the Gold Coast is of key importancewhen considering manners of protection from storm damage. The preservation of the

beach and beachfront development at Palm Beach is the initial stage of the ShorelineProject on the Gold Coast, in addition to protecting, and if practical, enhancing the beachamenity for the community, providing a sustainable, cost effective and integrated solution,

and avoid or mitigate environmental and social impacts. In conclusion, Palm Beachrequires priority action to protect local public and private infrastructure from storm surgeand erosion. An artificial reef will help armour the beach from storm and weatherdestruction. Extensive digital imagery, hydrographic survey and observational monitoring

shows that the reef implemented at Narrowneck on the Gold Coast was a successful

project in terms of both widening the beach (by 40metres over a decade) and reducing thepower and impact of harsh waves. It is evident that if the same strategy be implementedon Palm Beach, the coastline and community would react positively and the resulting

environmental protection caused by the artificial reef would be powerfully conclusive anddecisive.An artifical reef is a categorically better strategy than the original plan of a seawall and

sand replenishment. From a plan which would require a large ongoing cost, little localcommunity support, major disruption to coastal processes and only limited protectionfrom storm damage, in comparison to a smaller cost, more public approval, less

environment damage and greater protection from storm damage; an artificial reef is theright strategy to implement at Palm Beach.

4.3 List of References



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