Second International Engineering Heritage Conference Sydney Local Tour 20 September 2005

Transcription

1 Second International Engineering Heritage Conference Sydney Local Tour 20 September 2005 (Fold-out map of tour behind notes) North Head Sewage Treatment Works As Sydney developed its watercourses became open sewers draining to the harbour. The first pipe sewers were constructed in 1857, with the main ones joining to discharge into the harbour at Bennelong Point, where the Opera House is now. Eventually, pollution and the prevalence of water-borne diseases forced construction of ocean outfall sewers. These commenced in 1889 and discharged at Bondi and Malabar (south of the harbour entrance). North of the harbour, work commenced in 1916 on the Northern Ocean Outfall Sewer, which discharged at Bluefish Point, North Head. The three outfalls discharged raw sewage at the cliff face 7m below sea level. Bennelong Sewer 1869 Punch cartoon As population increased pollution of beaches by the raw sewage became unacceptable and gave rise to construction of the first major coastal treatment plant at Bondi, which was completed in the 1960's. The Bondi plant and the later one at Malabar (1975) provided primary treatment, while the North Head plant (1984) provided high rate primary treatment. All incorporated the removal of screenings, grit, grease, floatables and settleable solids and continued to discharge via the original submerged outlets. Despite this primary treatment, increasing bacteriological pollution, discolouration of the ocean and deposits on beaches (particularly of grease), forced extensive upgrading of the outfalls. This involved constructing three long tunnelled outfalls to diffuse effluent up to 4 km offshore in water up to 80 m deep, and upgrading the sewage treatment plants to improve the quality of the discharged effluent. (See Attachment 1 for basic data on Sydney s sewage ocean outfalls). The North Head treatment works serves an area of 470 sq. km and treats waste equivalent to that produced by around 1.2 million people. It provides primary treatment through screening, grit removal and sedimentation of the sludge, which is then thickened and dewatered and used in agriculture, forestry, landscaping and land rehabilitation. Around 320 million litres of primary treated waste water are discharged to the ocean each day through the outfall tunnel, at depths up to 65 metres. The tunnel has an internal diameter of 3.5 m and is 3.7 km long; the 36 diffusers have a 450mm internal diameter and are spaced at an average of 21 m. (See Attachment 2 for longitudinal sections of outfall tunnel and diffuser riser). About 2.2 million litres are used daily for cleaning the screens and other equipment. Sydney Water is undertaking improvement works at North Head Sewage Treatment Plant to ensure the plant can continue to perform in line with established environmental protection licence standards. The work will include installation of a water recycling facility that will reuse 1.5 million litres of wastewater each day for industrial purposes at the plant. This equates to a saving of around 550 million litres each year of drinking water presently used. North Fort and Royal Australian Artillery National Museum North Fort was completed in 1938 and although not firing a shot in anger during World War II, the guns were a significant deterrent to any potential attack on Sydney Harbour by a naval force. The Fort consisted of two 9.2 inch coastal guns which could rotate 360 degrees and had a range of 27km. The guns were supported by two searchlight elements and three 40mm Bofors anti-aircraft guns. LocalTour_Notes 1

2 In 1960 after 25 years of being fully manned and armed, North Fort was declared non-operational and the guns and most of their supporting infrastructure were removed. Now listed in the Australian Heritage Register, the entire complex is undergoing extensive restoration by volunteers and professionals dedicated to restoring to their original condition, the underground tunnel complex including the magazines, pump rooms, power station and medical dressing station. Adding to this impressive fortification is its unique location with sweeping views over the ocean and the harbour, all nestled amongst the natural flora and fauna of North Head and the Sydney Harbour National Park. North Fort is now the home of the Royal Australian Artillery National Museum devoted to the history of Australian gunners in their role in the many conflicts and peace-keeping operations that have involved Australia. The history of Australian artillery is on display at North Fort and includes an extensive range of guns from the colonial days to today, including medium to heavy field artillery, anti-tank, mortar, air defence and coastal artillery. Other equipment includes ammunition, searchlights and radar. The Museum houses a wide range of medals, uniforms, and an impressive library of books, maps and photographs covering the history of the Australian Artillery. Handling artillery shells, North Fort Quarantine Station (not on tour) From the beginning of colonisation in Australia, the arrival of each ship in Sydney Harbour carrying goods and settlers brought with it the dreaded prospect of epidemics. With smallpox, cholera, Spanish influenza, bubonic plague and other contagious diseases regularly sweeping the world, it became essential that the colony establish a quarantine facility. The combination of maritime convenience and geographic isolation made North Head the ideal location. The Quarantine Act was passed in 1832 and the Quarantine Station that was established, protected Australia for over 100 years. At peak periods there could be as many as 8 ships moored off Quarantine Beach, the Station would run out of accommodation, and residents would be forced to camp on surrounding hills in generally miserable conditions. 3 rd Class Accommodation The Quarantine Station proved no sanctuary for the passengers on the typhus ridden Lady McNaughton, which arrived in Sydney Harbour in 1837 after losing fifty four passengers en route. Thirteen more died after arrival in what were then described as "truly appalling conditions with a sense of misery, wretchedness and disease present everywhere." Captain Stokes of the Beagle wrote that he was able to identify the Quarantine Station by the number of tombstones whitening on the side of the hill. Over the years inmates whiled away their time carving ships badges and information about their journeys into the sandstone rock face near the wharf. With the advent of modern medicine and aviation, the Quarantine Station went into decline and was reduced geographically to its present 69 acres. At the turn of the 19 th century it was used to isolate residents of The Rocks after a bubonic plague outbreak, and following World War 1 soldiers returning from the battlefields of France were quarantined there in fear of an influenza outbreak. The Station was last used as emergency accommodation for people LocalTour_Notes 2

3 fleeing Darwin after the destruction caused by Cyclone Tracy on Christmas Eve 1974 and for Vietnamese orphans in the 1970's. In 1984 ownership passed from the State and Federal Governments to the National Parks and Wildlife Service for inclusion in the Sydney Harbour National Park. The Service regularly conducts a three hour ghost tour after sunset, where visitors are lead by guides through the winding unlit streets and buildings of the Station, listening to familiar stories of colonial life and the Station s often grizzly history, while tales turn more and more to ghostly activity. The National Parks and Wildlife Service is presently negotiating with a developer to lease the station as a hotel and to manage it for 45 years, amidst much opposition from the local and heritage community. Middle Head and Georges Heights Fortifications In 1801 a fort was built above Obelisk Bay to protect the new colony from a possible French attack. For the next 200 years the military had a significant presence on the headland. Three sets of fortifications were built on Georges Heights in the 1870s. They were part of a network of 'outer harbour' defences designed to fire at enemy ships as they entered the harbour. There were upgradings in the 1880s on the advice of British experts. Over the years the fortifications were modified as technology changed and new guns were installed. The invention of aircraft and long-range naval guns led to the dismantling of fortifications in the 1950s. Georges Heights became the site of a new military hospital during World War 1. During World War 2 Australia was forced to redesign its defence systems. A submarine net was placed across the harbour and new quick firing guns were installed at Georges Head. However, Japanese midget submarines made it past these defences into the harbour in May By 1944 the Army had scaled down its operations in the area as the port defence system was no longer effective. The guns were removed and the fortifications were dismantled during the 1950s and replaced by training and barrack facilities. In 1979 large areas of Defence land in the area became national park. More recently, the military has withdrawn from most of its remaining bases to more strategic locations. Much of the area is now under the control of the Sydney Harbour Federation Trust which intends making it a headland park. Early Aboriginal use and the long defence history of the peninsular will be interpreted, and there will be a network of walking trails. Garden Island Naval Dockyard and Captain Cook Graving Dock Serious development of Garden Island as a naval base for the Royal Navy commenced in the 1880s and by 1889 there were administration buildings, stores, a gaol, a chapel, barracks, a rigging shed, workshops and a chain and rigging store. By 1896 it was a well-equipped naval dockyard. In an 1893 building there is a well conserved hydraulically operated system comprising five lifting whips with cranes mounted on the external walls. When the Royal Australian Navy came into being in July 1911 it inherited the facility as its major ship-support base. Advances in ship design and scientific discoveries that led to radar and sonar during World War 2, brought changes in the engineering and skills employed. These took the dockyard from the steam age into diesel power, electronics, and the technology employed in modern ships and in sophisticated weaponry. LocalTour_Notes 3

4 Captain Cook Graving Dock The potential loss of docking facilities in Singapore during World War 2 gave rise to the construction of a graving dock in Sydney to accommodate capital ships, large merchant vessels and passenger liners cum troop transports. The Prime Minister announced the building of the Captain Cook Dock in May It was designed by Sir Alexander Gibb & Partners and built by a combination of government authorities. Excavation and quarrying of fill for the cofferdams was by the Public Works Department; construction of the cofferdams by the Maritime Services Board; and the concrete work was by the Sydney Water Board. The caissons were designed by Vickers Armstrong of Barrow-in-Furness and constructed within the cofferdam by the Sydney Steel Company. Most of the plant was manufactured in Britain, with only two shipments being lost through enemy action. The dock was built between Garden Island and Potts Point with the surrounding reclaimed area (30 acres) joining the island to the mainland. The dock is 1000 ft long with a 137 ft wide entrance and a depth of 45 ft i.e. 305m x 42m x 14m. The de-watering system comprises three pumps with 6 feet diameter suctions that can each discharge 70,500 gals/hour; they can de-water the dock in about 4 hours. Construction of the dock which took 4.5 years from 1941 to 1945 HMAS Vendetta in dock during wartime, ranks as one of the greatest civil engineering projects in Australia. The dock was first used on 1 March 1945, just 6 months before the end of the war in the Pacific (VJ Day) the end of World War 2 Hamerhead Crane In 1952 a 254 ton hammerhead crane was completed on the main fitting out wharf at Garden Island. The crane, which took six years to build, is 203 feet (62 m) high above wharf level and rests on foundations 90 feet (27.5 m) below the sea bed. It could lift 250 tons at 118 feet radius (36 m) and has a 40 ton auxiliary hoist. The crane was designed by Sir William Arrol with Sir Alexander Gibb & Partners as consultants and was built by the Sydney Steel Company Pty Ltd; all the mechanical and electrical equipment came from England. The crane has been retired from service for many years - it is now redundant and non-operational. It should be conserved instead of rusting away and being a roost for pigeons and gulls, but it is a conundrum as to how this might be achieved and who will pay. ADI Ltd In January 1996 the Government-owned Australian Defence Industries changed its name to become simply, ADI. Then in November 1999 it was fully privatised as ADI Limited when it was sold to Transfield Holdings and Thomson-CSF (now Thales). ADI s capabilities include: Project management; software engineering; information systems; systems integration, engineering and support; shipbuilding and maintenance; mine countermeasures systems; ordnance manufacture; mechanical, light, medium to heavy precision engineering and fabrication; design and manufacture of military and specialist vehicles; outsourcing; facilities management; provision of logistic services; electronic warfare support; aerospace and optronics services. The company conducts business throughout Australia and around the world and teams with leading international companies. ADI leases defined parts of Garden Island (including the Captain Cook dock) from the Australian Government and contracts to it for the repair and maintenance of naval shipping and equipment. It is also under contract for the maintenance of the Island s infrastructure. LocalTour_Notes 4

5 Attachment 1 Sydney s Sewage Ocean Outfalls Basic Data 1990 Malabar North Bondi Totals 1. Catchment Details Head Catchment Area (sq. km) Present Resident Population (Millions) Present Equivalent Population (Millions) Ultimate Equivalent Population (Millions) Flows (Ml/d*) Dry Weather Flow in Wet Weather Flow in Ultimate Wet Weather Flow * Megalitres per day 3. Capacity of Outfalls (Ml/d*) Basic Outfall Dimensions Length of Outfall Tunnel (km Shoreline to End of Diffusers (km) Shoreline to First Diffuser Finished Internal Diameter of Outfalls (m) Average Ocean Depth at Diffusers (m) Length of Diffuser Zone (m) Number of Diffusers Average Spacing of Diffusers (m) Number of Ports/Diffuser Note: For flows to reach the capacity of the Malabar and North Head Outfalls, major systems amplifications will be necessary LocalTour_Notes 5

6 Attachment 2 North Head Sewerage Ocean Outfall Longitudinal Section through Outfall Tunnel Section through Diffuser Riser LocalTour_Notes 6

7 North Head Sewage Treatment Works: North Fort and Royal Australian Artillery National Museum: Quarantine Station: Sources Sydney s Ocean Outfalls Planning & Implementation, Water Board January Sydney s Engineering Heritage and other sites, Engineers Australia North Fort brochure Middle Head and Georges Heights Fortifications: Reflections on a Maritime City, Sydney Harbour Federation Trust 2000 Sydney Harbour Federation Trust website The History and Heritage of East Port Jackson, notes for a heritage cruise, Michael Clarke Garden Island Naval Dockyard and Captain Cook Graving Dock: Map: Appendix F Captain Cook Graving Dock notes provided by The Naval Historical Society of Australia The Building of Our 254 Tonne Crane, Colin Stuart, Engineer in Charge of Construction, in Garden Island Sydney: From Settlement to City, Ed. Don Fraser The History and Heritage of East Port Jackson - notes for a heritage cruise, Michael Clarke NRMA (base map) LocalTour_Notes 7