RAIBOW BAY BEACH FIELD REPORT

Table of ContentsAbstract............................ P-3

1.0 Introduction....................................................................................................................................................................P-4Figure 1: Map showing Southern QLD beaches...........................................................................................................P-4

2.0 Methodology..................................................................................................................................................................P-53.0 Statement of Findings................................................................................................................................................... P-6

3.1 History of Rainbow Bay................................................................................................................................... P-6

3.2 Data Collection.................................................................................................................................................P-6

Table 1: Overall Data Collection at Rainbow Bay.....................................................................................p.6Table 2: Management Techniques............................................................................................................... p.6

3.2.1 Vegetation...................................................................................................................................p.63.2.2 Fencing........................................................................................................................................ P-7

Figure 2: Photograpgh of fegetation and fencing used at Rainbow Bay (Tweed Sand Bypass,

2010)............................................................................................................................................p.73.2.3 Seawall........................................................................................................................................ P-7

Figure 3: Photograph of the seawall located in front of Rainbow Bay Surf Club (Captured by

Lee.M.Winter)3.2.4 Pathways..................................................................................................................................... P-8

3.2.5 Sand Pumping System.................................................................................................................p.8Figure 4: Annotated aerial shots of Rainbow Bay from various years showing width fluctuation...................................................................................................................................p.8

4.0 Evaluation...................................................................................................................................................................... p.94.1 Table 3: Vegetation - Evaluation of vegetation as a management process..............................................p.94.2 Table 4: Fencing- Evaluation of fencing as a management process...........................................................p.94.3 Table 5: Seawalls - Evaluation of seawalls as a management process....................................................p.104.4 Table 6: Pathways - Evaluation of pathways as a management process...................................................p.10

5.0 Justification:.................................................................................................................................................................p.ll6.0 Bibliography:................................................................................................................................................................P-127.0 Appendix B:..................................................................................................................................................................P-13

Figure 5: Field Sketch of Rainbow Bay................................................................................................p.13Figure 6: Picture of Rainbow Bay Beach (taken 22.4.16)................................................................ p.13Link to TRESBP Fact Sheet................................................................................................................... p.14

Abstract:The coastal erosion management process at Rainbow Bay was analysed and evaluated for their effectiveness. It was found that the vegetation, fencing, pathways and seawall methods were sufficient and effective management processes. However, it is believed that if the current sand pumping system was enhanced, it would

be beneficial for the beach in a social, economic and environmental sense.

1.0 IntroductionSouth East Queensland's Rainbow Bay (Figure 1) has seen of a significant increase of coastal erosion since extending Tweed River's training wall in the 1960's. The effect of the extension deprived the beaches of natural sand migration through longshore drift. Numerous coastal management strategies have been implemented by the Gold Coast City Council, including the vegetation and fencing methods, as well as the TRESBP program (since 2001). This report will examine the effectiveness of the management process and make recommendations regarding the future of the beach.

Figure 1: Overview of Southern Gold Coast Beaches cUk' MX

Sourthem Gold Coast BeahcesIncluding Kirra Beach, Coolangatta Beach, Rainbow Bay Beach and Duranbah Beach

LegendBeach

? Beach Features

2.0 MethodologyIn preparation for the report on Rainbow Bay beach, several methods of data collection were conducted. This included a field trip to the Southern Queensland beaches on the 22nd of April, 2016. Whilst at the location, field sketches, measurement observations and photographs (see Appendix B) were collected all in one visit and at one point of time. Due to the limited visits and duration of stay, the data was prone to faults, thus being bias. Field sketches and photographs were also captured from a very narrow stretch at the beach; observations & measurements were constructed without adequate or appropriate equipment. Following tjne collection of primary data, secondary sources were collected from various sources. (Appendix A).

3.0 Statement of Findings3.1 History of Rainbow Bay

The state of Rainbow Bay is known to fluctuate in the width through-out certain times of the year (referrer to Appendix B). The beach also has touristic features such as the 'Rainbow Bay Surf Lifesaving Club' and Snapper Rocks that are located on the eastern-side of the beach. ^

3.2 Data CollectionTable 1: Overall Data Collection at Rainbow Bay on 22nd April 2016

Weather Conditions • FineWind Direction • SWWave Direction • WWave Frequency • 13 p/minWave Type • ConstructiveTide • High incoming (flood)HWM - LWM Distance « 16mSwash Zone • 11mBerm * Yes-scarpingLiving Fauna • Yes-seagullsVegetation • Beach grass, she-oak, morning glory,

pandanusHuman Impact • Yes - fencing, footprints, human

activity, peopleWidth of Beach • 60mEvidence of Erosion • Yes -scarpingMethods of Stabilisation • Plantation, thick grass, fencingDepth of Dunes • 4m

Table 2: Management Techniques; data collected 22nd April 2016

Distance • 20mCoverage • 50%Height <* 2-2.5mCondition ® Intact

Rainbow Bay has also implemented various techniques to maintain the amount of sand in its beach.3.2.1 Vegetation:Vegetation has been implemented into the area to secure the movement of sand. The roots of the plants grow and grip onto the sand, restraining movement of sand in the area. Some of the vegetation found in this area includes beach grass, she-oak, morning glory and pandanus (Appendix

A)' V

3.2.2 Fencing:To prevent erosion occurring on the plants, fences have been constructed to keep people and animals away from ruining the vegetation. The fence has been made from cut wood and a green, plastic mesh to allow water to flow through, but restrain as much sand movement as possible.

Helps contain over­growth of vegetation, keeping the beach tidy

Clearly defines out-of- bound areas to reduce

erosionConstructed from timber and has a

green mesh to prevent sand

Figure 2: Photograpgh of fegetation and fencing used at Rainbow Bay (Tweed Sand Bypass, 2010) cutAUM

3.2.3 Seawall:Further along the east coast, a seawall made from boulders had been placed to not only keep the sand on the inside of the wall compacted and less prone to erosion, but to be used as a visually appealing anti-erosion method.

Figure 3: Photograph of the seawall located in front of Rainbow Bay Surf Club (Captured by Lee.M.Winter)

Can complement really well with other features on the beach

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3.2.4 Pathway:

Located inshore from Rainbow Bay are pathways that have been employed for the convenience of easier transport and accessibility to locations nearby the beach. They are made from concrete and are commonly used not only by people who want to access Rainbow Bay, but for those who want to travel up or down the coastline of the beach.

3.2.5 Sand Pumping System:

The current sand pumping system, (AKA the TRESBP) has been a running system throughout all the Southern Gold Coast beaches ever since 2001. The system collects deposited sand caught by the jetty at the southern side of the Tweed River entrance and transports it to the northern beaches through underground pipes (see Appendix B for more information).

As seen in Figure 4, the TRESBP has kept the width of Rainbow Bay at a full level ever since it was implemented. Without the system, it is clearly evident that the beach was more depleted and had created a sand bar, creating an uneven ratio or sea and sand.

1988

1994

2005

flock* covered with

deposited Wr>dSandbar

coveredSind generating

near mountain

fcocks almost completely covered Sandbar

completely gone

Sand transferred to

1 U>*< amount1 of recks

K. x

1 Sandbar ■ ■ U'C'ftttki 1■ imposed

V t JSP

Figure 4: Annotated aerial shots of Rainbow Bay from various years showing width fluctuation.

4.0 EvaluationEven though the local council are using different techniques to manage erosion, some are noticeably more efficient than others.

4.1 Table 3: Vegetation - Evaluation of vegetation as a management process

VegetationSocial q Aesthetically ® Less Beach

pleasing ® Can look ugly if not• Beach deemed to be tended

invested inEconomic • Cheap

• May spread & grow bigger -> less money

® Large quantity isneeded -> more money

© May require tending-> hire gardeners

Environmental o Environmentally ® May destroy habitats offriendly current fauna

® Provides habitats for © May encouragenative insects unwanted fauna

Overview - Vegetation:

Overall/ vegetation is a great method of managing erosion. Plants not only look

aesthetically pleasing and are environmentally friendly, but are also inexpensive.

4.2 Table 4: Fencing- Evaluation of fencing as a management process

Social ® Visually pleasing © Plain looking/Visually© Less freedom/space for unappealing

children/animals to ® Less accessibility of thewonder

© Indicates safe areasbeach

Economical ° Made using cheap materials

© Efficiently sizedmaterial dimensions- less expensive

° Not durable © Easily damageable

Environmental • Environmentally © Increased areafriendly population -> more

o Minimal environment litteringdamage o Prevents native fauna

from entering area

Overview - Fencing:

Fencing is a very effective technique that should be encouraged. While

keeping the beach looking tidy, it is both economically and environmentally

friendly and consumes a minimal space on beaches.

4.3 Table 5: Seawalls - Evaluation of seawalls as a management process

SeawallsSocial ©

©©

Encourages social activitiesKeep area well kept Natural look

@

©

Not aesthetically pleasingPotentially dangerous

Economical © Cheaper than other © Expensive to constructmethods @ Large quantities are

© Long lasting/durable needed

Environmental © Constructed from © Limits Vegetationnatural materials © Interferes with natural

© Helps prevent land processeserosion

Overview - Seawalls:

Seawalls may not appeal to the citizens, but it is a low-costing method

that uses natural materials to blend with the environment. It also last a

longtime while does its job well.

4.4 Table 6: Pathways - Evaluation of pathways as a management process

PathwaysSocial O Offers multi-vehicle © Less natural scenery

access O Higher chance of© Can be decorated pedestrian accidents

Economical © Tourism rates increase © Less space for other© Variety of materials can features

be used to construct it © Large quantity usedEnvironmental © Encourages less human © Less vegetation

erosion © Reduction of potential© Provides a safe and

levelled walk plainhabitat of fauna

Overview - Pathways:

Providing pathways near a beach is crucial for a touristic site.

They provide access for most vehicles and encourage minimal

erosion.

5.0 Justification:After the evaluation of the management process currently at Rainbow Bay, it was noted that the width of the beach could be more sufficiently handled if a pumping system was implemented. Although the system would be quite costly and may harm the native fauna's habitual area, the beach itself would receive a consistent width all year round and provide the current TRESBP system a permanent area that it's excess sand could be transferred to. Therefore, by employing a sand pumping system into Rainbow Bay, it would assist not only Rainbow Bay's erosion management process, but the TRESBP system as well.

6.0 Bibliography:ID#45464, Airviewonline.com, 2016, "Tweed Heads And Coolangatta | Airview Online Aerial Stock Photo" Accessed 12 May 2016, URL: https://airviewonline.com/gallerv/view/45464/tweed-heads-and-

coolangattaLeemwinter.com, 2016, Accessed 22 May 2016 http://leemwinter.com/wp- content/uploads/2015/ll/2015-09-30-09.30.18.ipg

Seasonal beach changes at Rainbow Bay, Undated, "Seasonal beach changes at Rainbow Bay" Accessed

10 May 2016, URL:http://www.tweedsandbypass.nsw.gov.au/ data/assets/pdf file/0005/514859/rainbow-bay-beach-behaviour.pdf

7.0 Appendix B:

Figure 5: Field Sketch of Rainbow Bay

Figure 6: Picture of Rainbow Bay Beach (taken 22.4.16) /

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Link to TRESBP Fact Sheet:httn-//www..wMd?anrihvmSS.nsw.Bov.au/ data/assets/pdf file/0009/49986<)/FACT SHEET 1 What is TRESBPjj

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