THE STRAND REDEVELOPMENT MANAGING COASTAL IMPACT – A SUCCESS STORY

Author: Dawson Wilkie, Director Engineering Services, City Council, PO Box 1268 Townsville QLD 4810

DAY 2 – SATURDAY MORNING SESSION

WELCOME FROM TOWNSVILLE people. The Strand however had seen many sky shows as well as VP 50 and Townsville is a major regional city in North celebrations for the battle of the . . It is some 1800km north of In 1993 Council conducted a “design so it has a need to be independent competition” to start the process of and self-supportive. We affectionately call it developing and improving the Strand. The the capital of . competition attracted wide interest with many submissions received. Gillespie WHAT IS TOWNSVILLE? Peddle Thorp – Brisbane, submitted the winning entry. The designs included a number of interesting design concepts, Townsville is a mixture of light industry and including piles in the sea with replicas of is home to Queensland’s third largest marine animals on them, a lagoon to return industrial port. The port is an important part the area to its pre settled configuration, and of the City and has played a vital role in the many others. Unfortunately there was limited economic increase of the cane, fertiliser and funds and these works were not undertaken. mineral industries. Whilst the port is very In addition the Council over the years had important to Townsville’s economic growth it struggled with the problem of sand loss and also has a down side. The regular dredging what to do. of platypus channel has prevented the regular littoral sand drift, as it now is trapped In 1996 as a result of a further dredging in the channel. This in addition to the application by the Townsville Port Authority construction of a dam and weirs on the Ross Sinclair Knight Mertz were commissioned to River means that the Strand is now starved investigate beach erosion issues in of sand and that any sand lost in extreme Townsville. (1) This report was events is lost forever. In co-operation with comprehensive and forms the basis of the port, a number of other factors caused ongoing investigations. The “problems“ that major disruption to the flow of sand including Townsville faced in sand loss were four fold: the construction of the breakwater marina. - 1. The Townsville Port Authority contributed HISTORY OF THE STRAND to the lack of sand by way of the modification of the beachfront, The Strand was the coastal icon of reclamation dredging and maintenance Townsville however without the natural dredging of the Platypus channel. replenishment of sand it was slowly losing The report estimated that approximately its appeal. was a large 48,000 tonnes of suitable beach sand is cyclone that hit the coast in 1971. The lost annually. damage to the City was significant, as was the damage to the sea wall at the Strand. 2. The construction of the Dam Approximately 55% of the sea wall was and three downstream weirs also replaced with a new larger boulder prevented the flows of sediment by:- revetment with a nominal facing slope of § Trapping sediment behind their walls. 1:1.5 and a raised crest level to 6.1 meters § The flood retarding effect of the weirs, which was approximately 1m higher than the in that they cause water to flow more original wall. The high rock wall however slowly resulting in a lower sediment meant that the beach was lost to the view of carrying capacity.

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PDF created with FinePrint pdfFactory trial version http://www.fineprint.com § The report estimated that the weirs and night (a traditionally dry dam trap approximately 68,000 tonnes place) recorded in excess of 474 mm in a per year. period of five hours, other unofficial rain gauges recorded in excess of 700 mm for 3. The Queensland Department of Natural the same time. This translated into a record Resources and Mines allow the rainfall event of anywhere between 1 in 120 extraction of up to 260,000 tonnes per year up to 1 in 233 year event, depending year from the Ross River upper reaches. on which expert you speak to. Sand supply rates into the Ross River system are estimated at 34,000 tonnes Sid was around long per year. The net loss is not a simple enough to whip up a strong swell, which subtraction but could be in the order of stripped the remaining sand off the Strand. 200,000 tonnes per year. A severely weakened rock wall was then breached both by ocean swell and storm 4. Storm water flows through urban water runoff. Approximately 120 m of wall catchments is usually of higher velocity was lost along with the road and other however with improved drainage infrastructure. In all about 60% of the wall structures, sediment flows are was damaged. Again financial assistance predominately debris and waste from the was granted in the order of $1.4m urban area. The urban catchment also comprises only a small part of the total THE REPAIR catchment (approximately 42 square kilometers of approximately 750 square The old saying of “good things come out of kilometers). adversity” fell true for Townsville. The Premier of Queensland, standing on a wind The report identified a long-term problem swept rock front after having seen the that had to be resolved. flooding and hardship, agreed that to allow the City to continue, the State Government THE DISASTER No. 1 would allocate significant funds to repair the Strand. In March 1997 the residents of Townsville were warned of the approaching tropical The January 1998 event had started the . Before crossing the planning. We had the concept for a coastline the cyclone disintegrated into a recreational design and an understanding of tropical rain depression and settled over the the technical problems. It was also decided city. The result was a declared disaster, to design for a much higher level of with many homes flooded and people immunity and 1 in 100 year event became displaced. The Strand experienced a the design criteria. severe wind storm event, most likely in the order of 1 in 50 year event, and suffered a The usual problems were there. What to do major loss to the remaining sand. The with the storm water outlets that don’t look persistent wave action over several weeks attractive flowing across the sand. How to during ex-cyclone Justin resulted in the keep the sand etc. The result was that we undermining of the central portion and had to step in and do what nature once did. subsequent failure of approximately 33% of The saving grace was that in all but extreme the wall. The event was of such magnitude events the sand was held in the Cleveland that Natural Disaster Financial Assistance Bay basin and was just moved around to the Arrangements were triggered. The costing tune of 70% south and 30% north. All we of the repair was $1.8m. need to do was to truck it back!

THE DISASTER No. 2 THE PROPOSAL

th The evening of Saturday 10 January 1998 The problem was assessed and Council was a land mark day in Townsville. All for decided that whatever solution was adopted the wrong reasons. During the course of the it had to be a long-term solution. It was from

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PDF created with FinePrint pdfFactory trial version http://www.fineprint.com this that the headland concept was shallow water with a gently shoaling seabed introduced. The idea of compartmentalizing that allows larger waves to break before the beach and increasing the time the sand reaching shore. was trapped solved a number of problems. It remedied the stormwater outlets, gave Other waves considered included those Council some land to do something with as generated by a cyclone in the Coral Sea. well as reduced the ongoing maintenance These waves were potentially the largest but costs for sand replacement. were attenuated greatly as they passed over the shallow . Also waves What we did generated between the Great Barrier Reef and the coastline were considered. These The aims of the redevelopment were: waves set the design criteria. ¨ Secure the coastline with a civil structure designed and constructed to For the Storm Tide Frequency of 100 years withstand a 1:100 year storm event; the Storm Tide level was 3.1m, the water ¨ Restore the foreshore using a technique depth was 4.7m and the maximum wave designed to minimise the need for future was 2.8m. wall maintenance and sand replenishment; All options were considered with the ¨ Redevelop by reinstating a beach optimum protection being a beach that in the alignment slightly offshore, providing long term equilibrium can be maintained with greater opportunities for improved minimal effort. Given that the beach had amenity and passive recreation been relatively stable prior to those external opportunities; sand supply effects a beach system seemed ¨ Redevelop to create stable “sandy to be the answer. It also met some of the beach” compartments and extend active expectations of Council for recreational recreation such as swimming and facilities. fishing; ¨ Provide all of the above and, at the The concept of foreshore protection and same time, minimise the risk of tidal land reclamation is often based on environmental harm. placement of large quantities of sand with the realisation that nature will eventually Council had retained Coastal Engineering create the beach profile. While protection Solutions as their consultant after cyclone through rock armoring is by no means a new Justine. They were given the brief to design technique, its application is an inexact a wall to provide the desired protection. The engineering science. Beach Protection Authority of Queensland had commissioned extensive storm tide The reclamation of the land from the sea studies for Townsville. The following table was undertaking by the placement of the was developed: - ‘shot rock’ causeway. This was utilised to Storm Frequency Storm Tide Level not only provide a stable working platform 5 2.2m for heavy machinery but also to minimise the 10 2.2m loss of fines during the construction of the 20 2.5m revetment walls. 50 2.8m 100 3.1m The beaches were designed using state of the art modelling software to model both the The Highest Astronomical Tide is 2.2m. It expected seasonal movements of the was therefore theoretically possible but beaches, and the beaches response to highly unlikely for a storm tide to reach 4 to storm wave activity. The modelling was part 6m. Fortunately most cyclones have of a wider coastal processes study which crossed the coast at a period near low tide. examined in detail the coastal processes of the Cleveland Bay foreshores for both the Townsville is shore side of Cleveland Bay existing and future developed cases. with a wave set up in the order of 2m but with a short wave period. The bay is

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PDF created with FinePrint pdfFactory trial version http://www.fineprint.com The project represents the innovative use of § preferred operation and construction soft engineering solutions to solve the methodologies described in Environmental foreshore erosion problems. It serves a Management Plans such as: unique double purpose in that it uses a - maintaining water quality values structural foreshore protection solution in the - transporting materials to the site form of beaches to create an extensive - placing rock, fill and sand recreational beach for the public. - managing chemicals and fuels - incident and spill response plans The project involved the construction of - minimising dust, noise or other three headlands which feature recreational environmental nuisance facilities, restaurants and headquarters for - measuring and assessing marine lifesavers. The headlands were devised for impacts. a dual role. Apart from their public amenity, the headlands will protect the new seawall and beach. They are in areas that have ENVIRONMENTAL VALUES IN been most vulnerable to cyclone damage PLANNING and are designed to trap sand and break the force of waves. The project objectives required completion in accordance with statutory requirements In all 250,000 tonnes of armor rock, 400,000 and engineering and environmental tonnes of sand, 390,000 tonnes of fill 70,000 approvals. The applicable environmental sq. m of turf, 16,000 trees and shrubs, 900 approvals, standards and guidelines were: palms and 22,5000 native groundcover Harbours Act 1955; Fisheries Act 1994; plants were required to complete the Beach Protection Act 1968; Coastal protection program. Protection and Management Act 1995; Environment Protection Act 1994; Great COMMITMENT TO ENVIRONMENTAL Barrier Reef Marine Park Act 1975; World RESPONSIBILITIES Heritage Properties Conservation Act 1983; State Development and Public Works The waters of Cleveland Bay, immediately Organisation Act 1971, and Numerous offshore from mean low water along The pieces of Legislation and Approval Strand fall within the Great Barrier Reef conditions. World Heritage Area. The area is also listed on the National Estate. The nearest portion MINIMISING ENVIRONMENTAL of the Great Barrier Reef Marine Park is IMPACTS approximately 2km west of the RockPool. Redevelopment of the Strand required tight The Strand redevelopment required controls to ensure that environmental values appropriate controls and monitoring to were not compromised. Intensive ensure that environmental values were not monitoring of turbidity and seagrass health compromised, owing to the proximity of an also occurred outside the development area of outstanding universal natural value. envelope to assess ambient conditions and the overall performance of the civil works. Numerous aspects of environmental management were adopted at the site Various methods have been adopted on the including: Redevelopment site to provide a mixture of § an Environmental Management System risk minimisation and mitigation of framework consistent with ISO 14000 environmental effects including: series with elements such as: - staff and management responsibility § Restricting physical disturbance to - environmental awareness training within the “envelope of the footprint” of - communication and reporting Redevelopment site shown on design - documentation and records, and drawings. A Marine Monitoring Program was implemented, as agreed to by the

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PDF created with FinePrint pdfFactory trial version http://www.fineprint.com Scientific Advisory Group, as described below exposed fill material to limit below. the egress of poor quality § Placing fill, rock and sand into a marine stormwater. environment has inherent problems in - minimising the ‘fines’ content of that it causes turbidity. Turbidity plumes sand imported to the site. have been caused and have occurred, - depositing sand along a beach frequently at times, beyond the crest allowing flood and ebb tidal “envelope of the footprint”. However, it action to naturally redistribute is considered that without the level of imported sand (rather than push environmental management actions sand direct into the sea). adopted, the frequency and magnitude of turbidity would have been greater § Refuelling and minor maintenance off- than that observed. There were several site inside a secure, HTPE liner. means of limiting or controlling the § Oil and fuel spill readiness (should a generation of turbidity beyond the machine fall into the water) with “envelope” including: absorbent material and floating booms. - using shot rock material of good § Dust suppression by tanker trucks quality (with small amounts of watering exposed sediments and associated dirt and fines) roadways. - lining the inside of shot rock berms § Adhering to limited work hours (7am to 6 and outside of fill platforms with pm) six days per week to reduce noise geotextile fabric to prevent long- and impact on amenity of the area. term erosion and sediment losses Nighttime work was required to to the ocean (though some short- excavate the toe of headland rockwalls term loss of fines to the water during November 1998. column did occur) § Importing fill, rock and sand along a - excavating the toe of headland predetermined road transport route. rockwalls at low tide when the risk of resuspending excavated marine COMMITMENT TO ONGOING sediments was reduced MONITORING AND ASSESSMENT (excavation of marine sediments and replacement with armour rock was required for structural Ongoing monitoring programs of the area integrity) surrounding the Strand will also attribute to - preventing the entry of machinery the sustainability of the development. These below the tide level programs include: - installing and maintaining silt curtains around the first 3 § Turbidity Monitoring: headlands to limit the turbidity to Two types of turbidity monitoring were inside the ‘envelope of the undertaken - Instantaneous Events and footprint’. Large tidal ranges and Long-term Turbidity Levels. Seagrass wind stress made these difficult to monitoring and noise monitoring are also keep in place though, at times, being monitored and will continue to be. capture of turbidity inside the curtains meant that ambient light THE RESULT levels outside the ‘envelope’ were preserved. Townsville City Council needed to design a - lining the inside of realigned wall foreshore protection system but also with geotextile fabric prior to incorporate a design that would return the armouring with rock. This Strand back to the residents and visitors to technique minimised the area of fill the region. material exposed to rain and runoff. The Strand now includes two stinger - using sand imported to the site to enclosures, a basketball court, water play form a downstream filter bund park, cafes/restaurants, children’s enclosed

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PDF created with FinePrint pdfFactory trial version http://www.fineprint.com play area, BBQ’s, public toilets and various exercise obstacles along the boulevard. Every aspect of accessibility to the Strand The Tobruk Pool renovations, funded foreshore has been assessed and partially by Townsville City Council, which implemented to make the experience of included a new 25-metre pool, two-way visiting the Strand an enjoyable one. kiosk, gymnasium, clubhouse and refurbished foyer were incorporated into the Areas have been designed with age groups Strand redevelopment. The Picnic Bay Surf in mind. A safe equal access playground Lifesaving Club took the opportunity to build was developed where younger children of all their new $400,000 headquarters on the ability can play and develop their skills. Burke Street headland. The 60 metre Picnic areas and barbecues are also Strand Pier was constructed on the Stuart included close to this young family facility. A Street Headland and provides a venue for “Teen Park” with equipment orientated the keen fisherman. towards teenagers has also been included in the design. The Strand Redevelopment has been aimed at the community with access being a major Care was taken to ensure all age groups contributing factor to its success. Plenty of could use the Strand. An equal access parking is provided the entire length of the consultant was employed to over view the foreshore with off street parking also design even to the abilities of wheel chair provided. The lighting in all areas has been bound people being able to use the rod improved to provide a high level of safety holders provided for people fishing. along with the introduction of regular security patrols. The Strand now offers a friendly and relaxed atmosphere for locals and visitors to Pedestrian crossings have been installed Townsville. Its inclusiveness of people of and traffic management procedures have various ages and interests, visual been put in place in the form of roundabouts attractiveness, proximity to the sea and city, and speed humps. Taxi ranks and Bus cleanliness and sense of safety, and range Stops are provided at points along the of recreational and social opportunities Strand, with bus routes now incorporating available to the community have all been these areas into their schedules. Bicycle highlighted as attributes. On an average lanes are also becoming a prominent feature week over 60,000 people visit the Strand to on Townsville roads making access to the take advantage of the amenities available Strand via a bicycle much safer. for use by the public.

DISABILITY ACCESS CONCLUSION

Access for people with disabilities was a Through an open approach with both major factor in the design of the Strand legislators and the community Townsville therefore all crossings and entryways are City Council has been able to transform a suitable for wheelchair access including the disaster area into an icon for the City. Co- main restaurants and cafes. There is plenty operation between all those concerned of disabled parking spaces along the entire allowed the work in an environmentally length of the foreshore (twice the Australian significant part of the Great Barrier Reef Standard and strategically located). Marine Park.

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PDF created with FinePrint pdfFactory trial version http://www.fineprint.com REFERENCES

Beach Erosion Issues Prepared by Sinclair Knight Mertz for the Townsville Port Authority March 1996

Strand Rejuvenation Prepared by Coastal Engineering Solutions for the Townsville City Council

Submission for Special Funding Consideration – The Strand Redevelopment Prepared by Townsville City Council for the Queensland State Government

The Strand Waterpark

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