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Little Barrier Island/Te Hauturu-o-Toi was declared a nature reserve on 26 September 1895. It was New Zealand's first nature reserve. During the period when the island was occupied by Māori, as much as a third of the Island was cleared of forest. However, since the acquisition of the land by the New Zealand government, all but 20 hectares of the island have been reforested. The Department of Lands and Survey became responsible for the Island, and employed a caretaker. Access is heavily restricted for conservation reasons, and the island is uninhabited except for rotational conservation staff, scientists and rangers under the authority of the Department of Conservation.
In the late 1950s and early 1960s the caretaker, RH Blanshard, and his wife were the only inhabitants. Blanshard was provided with photographic materials by the Department, and many of his photographs showing the landscape and the native birds are filed on an Auckland survey file [BAAZ 1109/153a]. Here are some examples, showing kereru, tui and a little blue penguin.
These images are based in the Auckland Regional Office of Archives New Zealand. For further enquiries regarding these images please email Auckland.Archives@dia.govt.nz
Archives New Zealand reference: BAAZ A557 153/a 3/637 4 collections.archives.govt.nz/web/arena/search#/?q=R21925582
For updates on our On This Day series and news from Archives New Zealand, follow us on Twitter twitter.com/ArchivesNZ
Material from Archives New Zealand Te Rua Mahara o te Kāwanatanga
Amelie, Stella, John Aven, playing in the sand by the creek. Barrier Lake, Bow Valley Provincial Park, Kananaskis Country, Alberta
Dartford Creek Barrier seen from the West, the Crayford side of the creek. On the bank beyond was where the Longreach Tavern once stood, this was in Joyce Green.
The joy of the niftyfifty set to f1.8 - and then down at ground level to capture some Thames Barrier bokeh - have a great weekend
Your usual modern ticket barrier, It's very small for a station of Eddingham's size however it's the right size to fit in the entryway between the station building and the concourse. I'm more fussed about the looks than the actual size and I'd say it's a pretty accurate model!
Suckerfish follow our sailboat as we leave Low Isle on the Great Barrier Reef, off the east coast of Australia.
Thames Barrier is a large flood control structure on the River Thames, constructed between 1974 and 1982 at Woolwich Reach, and first used defensively in 1983.[1] It is the world's second largest movable flood barrier (the largest is the Maeslantkering in The Netherlands).
Located downstream of central London, the barrier's purpose is to prevent London from being flooded by an exceptionally high tide moving up from the sea, often exacerbated by a storm surge. It only needs to be raised for the duration of the high tide; at ebb tide it can be lowered to release upstream water that backs up behind it. On the northern bank it lies in the area of Silvertown in the London Borough of Newham. On the southern bank it lies in the New Charlton area of Charlton in the London Borough of Greenwich.
Built across a 572 yard wide stretch of the river, the barrier divides the river into four 200 feet and two 34 yd navigable spans and four smaller non-navigable channels between nine concrete piers and two abutments. The flood gates across the openings are circular segments in cross section, and they operate by rotating, raised to allow "underspill" to allow operators to control upstream levels and a complete 180 degree rotation for maintenance. All the gates are hollow and made of steel up to 1½ inches thick. The gates fill with water when submerged and empty as they emerge from the river. The four large central gates are 220 feet long, 35 feet high (above local ground level) and weigh 3,500 tonnes; the outer two gates are 100 feet. Additionally, four radial gates by the riverbanks, also 100 feet long, can be lowered. These gate openings, unlike the main six, are non-navigable.
Before 1990, the number of barrier closures was one to two per year on average. Since 1990, the number of barrier closures has increased to an average of about four per year. In 2003 the Barrier was closed on 14 consecutive tides. The barrier was closed twice on 9 November 2007 after a storm surge in the North Sea which was compared to the one in 1953.
The concept of the rotating gates was devised by Charles Draper. The barrier was designed by Rendel, Palmer and Tritton for the Greater London Council and tested at HR Wallingford Ltd. The site at Woolwich was chosen because of the relative straightness of the banks, and because the underlying river chalk was strong enough to support the barrier. Work began at the barrier site in 1974 and construction, which had been undertaken by a Costain/Hollandsche Beton Maatschappij/Tarmac Construction consortium,[2] was largely complete by 1982. In addition to the barrier itself the flood defences for 11 miles down river were raised and strengthened. The barrier was officially opened on 8 May 1984 by Her Majesty the Queen Elizabeth II. Total construction cost was around £534 m (£1.3 billion at 2001 prices) with an additional £100 m for river defences. The barrier was originally designed to protect London against a flood level with a return period of 100 years in the year 2070 after which the protection would decrease but be within acceptable limits. This defence level included long term changes in sea and land levels as understood at that time (c. 1970). Since then sea level rise due to global warming has been identified. Based on current estimates[3] the barrier will be able to cope with projected sea level rises until around 2060–2070 and is expected to serve its full term. Since 1982 (up to 2007) the barrier has been raised over 100[4] times; further, it is raised every month for testing. The barrier was originally commissioned by the Greater London Council under the guidance of Ray Horner. After the 1986 abolition of the GLC it was operated successively by Thames Water Authority and then the National Rivers Authority until April 1996 when it passed to the Environment Agency.
In 2005, a suggestion was made public that it might become necessary to supersede the Thames Barrier with a much more ambitious 16 km (10 mi) long barrier across the Thames Estuary from Sheerness in Kent to Southend in Essex.[5]
London is quite vulnerable to flooding. A storm surge generated by low pressure in the Atlantic Ocean sometimes tracks eastwards past the north of Scotland and may then be driven into the shallow waters of the North Sea. The storm surge is funnelled down the North Sea which narrows towards the English Channel and the Thames Estuary. If the storm surge coincides with a spring tide then dangerously high water levels can occur in the Thames Estuary. This situation combined with downstream flows in the Thames provides the triggers for Flood defence operations.
According to Gilbert & Horner on 7 December 1663 Samuel Pepys recorded in his diary "There was last night the greatest tide that ever was remembered in England to have been in this river all Whitehall having been drowned". In 1236 the river is reported as overflowing "and in the great Palace of Westminster men did row with wherries in the midst of the hall". (Gilbert & Horner - 1984). Fourteen people died in the 1928 Thames flood, and after 307 people died in the UK in the North Sea Flood of 1953 the issue gained new prominence.
The threat has increased over time due to the slow but continuous rise in high water level over the centuries (20 cm / 100 years) and the slow "tilting" of Britain (up in the north and down in the south) caused by post-glacial rebound.
Early proposals for a flood control system were stymied by the need for a large opening in the barrier to allow for vessels from London Docks to pass through. When containerization came in and a new port was opened at Tilbury, a smaller barrier became feasible with each of the four main navigation spans being the same width as the opening of Tower Bridge.
An incident which had the potential to be catastrophic for London occurred on 27 October 1997. The dredger, MV Sand Kite, sailing in thick fog, collided with one of the Thames Barrier's piers. As the ship started to sink she dumped her 3,300 tonne load of aggregate, finally sinking by the bow on top of one of the barrier's gates where she lay for several days. Initially the gate could not be closed as it was covered in a thick layer of gravel. A longer term problem was the premature loss of paint on the flat side of the gate caused by abrasion. One estimate of the cost of flooding damage, had it occurred, was around £13 billion.[6] The vessel was refloated in mid-November 1997.
The barrier was closed twice on 9 November 2007 after a storm surge in the North Sea which was compared to the one in 1953.[7] The main danger of flooding from the surge was on the coast above the Thames Barrier, where evacuations took place, but the winds abated a little and, at the Thames Barrier, the 9 November 2007 storm surge did not completely coincide with high tide.[8]
A Thames Barrier flood defence closure is triggered when a combination of high tides forecast in the North Sea and high river flows at the tidal limit at Teddington weir indicate that water levels would exceed 4.87 m in central London. Forecast sea levels at the mouth of the Thames Estuary are generated by Met Office computers and also by models run on the Thames Barrier's own forecasting and telemetry computer systems. About 9 hours before the high tide reaches the barrier a flood defence closure begins with messages to stop river traffic, close subsidiary gates and alert other river users. As well as the Thames Barrier, the smaller gates along the Thames Tideway include Barking Barrier, King George V Lock gate, Dartford Barrier and gates at Tilbury Docks and Canvey Island. Once river navigation has been stopped and all subsidiary gates closed, then the Thames Barrier itself can be closed. The smaller gates are closed first, then the main navigable spans in succession. The gates remain closed until the tide downstream of the barrier falls to the same level as the water level upstream.
After periods of heavy rain west of London, floodwater can also flow down the Thames upstream from London. Because the river is tidal from Teddington weir all the way through London, this is only a problem at high tide, which prevents the floodwater from escaping out to sea. From Teddington the river is opening out into its estuary, and at low tide it can take much greater flow rates the further one goes downstream. In periods when the river is in flood upstream, if the gates are closed shortly after low tide, a huge empty volume is created behind the barrier which can act as a reservoir to hold the floodwater coming over Teddington weir. Most river floods will not fill this volume in the few hours of the high tide cycle during which the barrier needs to be closed. If the barrier was not there, the high tide would fill up this volume instead, and the floodwater could then spill over the river banks in London.
Europhoenix Class 37/6, 37608 "Andromeda" - leased to Rail Operations Group (ROG) - waits time with 5M59 13:41 Crewe South Yard to Leicester Loco Inspection Point. On the rear of the rake of barrier coaches is the former Northern Belle-liveried Class 57/3, 57305.
(Photographs taken on organised tour of Freightliner's Crewe Basford Hall yard.)
Crews add asphalt to make room for concrete traffic barriers at Evergreen Point Road as eastbound lanes shift to the north. This change, made during the weekend closure of SR 520 Oct. 19-21, 2012, will make room for a new median transit stop.
Je suis une barrière bleue, mais comme une autre cousine de la commune nuit est ma teinte, et mon avenir dirait-on .
Plozévet, Finistère, Bretagne France .
Photographie J-P leroy, droits réservés .
The Thames Barrier is the world's second largest movable flood barrier. It is a flood control structure located downstream of central London. The barrier's purpose is to prevent London from being flooded by an exceptionally high tide moving up from the sea, often exacerbated by a storm surge. It only needs to be raised for the duration of the high tide; at ebb tide it can be lowered to release upstream water that backs up behind it. On the northern bank it lies in the area of Silvertown in the London Borough of Newham. On the southern bank it lies in the New Charlton area of Charlton in the London Borough of Greenwich.
Historical needs for a barrier
London is quite vulnerable to flooding. A storm surge generated by low pressure in the Atlantic Ocean sometimes tracks eastwards past the north of Scotland and may then be driven into the shallow waters of the North Sea. The storm surge is funnelled down the North Sea which narrows towards the English Channel and the Thames Estuary. If the storm surge coincides with a spring tide then dangerously high water levels can occur in the Thames Estuary. This situation combined with downstream flows in the Thames provides the triggers for flood defence operations.
The threat has increased over time due to the slow but continuous rise in high water level over the centuries (20 cm / 100 years) and the slow "tilting" of Britain (up in the north and west, and down in the south and east) caused by post-glacial rebound.
Fourteen people died in the 1928 Thames flood, and after 307 people died in the UK in the North Sea Flood of 1953 the issue gained new prominence.
Early proposals for a flood control system were stymied by the need for a large opening in the barrier to allow for vessels from London Docks to pass through. When containerization came in and a new port was opened at Tilbury, a smaller barrier became feasible with each of the four main navigation spans being the same width as the opening of Tower Bridge.
Design and construction
One of the gates in underspill (March 2007)
The concept of the rotating gates was devised by Charles Draper. The barrier was designed by Rendel, Palmer and Tritton for the Greater London Council and tested at HR Wallingford Ltd. The site at Woolwich was chosen because of the relative straightness of the banks, and because the underlying river chalk was strong enough to support the barrier. Work began at the barrier site in 1974 and construction, which had been undertaken by a Costain/Hollandsche Beton Maatschappij/Tarmac Construction consortium,[1] was largely complete by 1982. In addition to the barrier itself the flood defences for 11 miles down river were raised and strengthened. The barrier was officially opened on 8 May 1984 by Her Majesty Queen Elizabeth II. Total construction cost was around £534 m (£1.3 billion at 2001 prices) with an additional £100 m for river defences.
Built across a 520-metre (570 yd) wide stretch of the river, the barrier divides the river into four 61-metre (200 ft) and two about 30 metre (100 ft) navigable spans. There are also four smaller non-navigable channels between nine concrete piers and two abutments. The flood gates across the openings are circular segments in cross section, and they operate by rotating, raised to allow "underspill" to allow operators to control upstream levels and a complete 180 degree rotation for maintenance. All the gates are hollow and made of steel up to 40mm thick. The gates fill with water when submerged and empty as they emerge from the river. The four large central gates are 20.1 metres (66 ft) high and weigh 3,500 tonnes. [2] Four radial gates by the riverbanks, also about 30 metres (100 ft) wide, can be lowered. These gate openings, unlike the main six, are non-navigable.
Prediction for operation
A Thames Barrier flood defence closure is triggered when a combination of high tides forecast in the North Sea and high river flows at the tidal limit at Teddington weir indicate that water levels would exceed 4.87 m in central London. Forecast sea levels at the mouth of the Thames Estuary are generated by Met Office computers and also by models run on the Thames Barrier's own forecasting and telemetry computer systems. About 9 hours before the high tide reaches the barrier a flood defence closure begins with messages to stop river traffic, close subsidiary gates and alert other river users. As well as the Thames Barrier, the smaller gates along the Thames Tideway include Barking Barrier, King George V Lock gate, Dartford Barrier and gates at Tilbury Docks and Canvey Island. Once river navigation has been stopped and all subsidiary gates closed, then the Thames Barrier itself can be closed. The smaller gates are closed first, then the main navigable spans in succession. The gates remain closed until the tide downstream of the barrier falls to the same level as the water level upstream.
After periods of heavy rain west of London, floodwater can also flow down the Thames upstream from London. Because the river is tidal from Teddington weir all the way through London, this is only a problem at high tide, which prevents the floodwater from escaping out to sea. From Teddington the river is opening out into its estuary, and at low tide it can take much greater flow rates the further one goes downstream. In periods when the river is in flood upstream, if the gates are closed shortly after low tide, a huge empty volume is created behind the barrier which can act as a reservoir to hold the floodwater coming over Teddington weir. Most river floods will not fill this volume in the few hours of the high tide cycle during which the barrier needs to be closed. If the barrier was not there, the high tide would fill up this volume instead, and the floodwater could then spill over the river banks in London.
Barrier closures and incidents
Before 1990, the number of barrier closures was one to two per year on average. Since 1990, the number of barrier closures has increased to an average of about four per year. In 2003 the Barrier was closed on 14 consecutive tides.
An incident which had the potential to be catastrophic for London occurred on 27 October 1997. The dredger, MV Sand Kite, sailing in thick fog, collided with one of the Thames Barrier's piers. As the ship started to sink she dumped her 3,300 tonne load of aggregate, finally sinking by the bow on top of one of the barrier's gates where she lay for several days. Initially the gate could not be closed as it was covered in a thick layer of gravel. A longer term problem was the premature loss of paint on the flat side of the gate caused by abrasion. One estimate of the cost of flooding damage, had it occurred, was around £13 billion.[3] The vessel was refloated in mid-November 1997.
The barrier was closed twice on 9 November 2007 after a storm surge in the North Sea which was compared to the one in 1953.[4] The main danger of flooding from the surge was on the coast above the Thames Barrier, where evacuations took place, but the winds abated a little and, at the Thames Barrier, the 9 November 2007 storm surge did not completely coincide with high tide.
Ownership / operating authority
The barrier was originally commissioned by the Greater London Council under the guidance of Ray Horner. After the 1986 abolition of the GLC it was operated successively by Thames Water Authority and then the National Rivers Authority until April 1996 when it passed to the Environment Agency.
Future
The barrier was originally designed to protect London against a flood level with a return period of 1000 years in the year 2030 after which the protection would decrease but be within acceptable limits [6]. This defence level included long term changes in sea and land levels as understood at that time (c. 1970). Since then sea level rise due to global warming has been identified. Based on current estimates[7] the barrier will be able to cope with projected sea level rises until around 2060–2070 and is expected to serve its full term. Since 1982 (up to 2007) the barrier has been raised over 100[8] times; further, it is raised every month for testing.
In 2005, a suggestion was made public that it might become necessary to supersede the Thames Barrier with a much more ambitious 16 km (10 mi) long barrier across the Thames Estuary from Sheerness in Kent to Southend in Essex.
Wikipedia
Barrier - A rusted and weathered grill, part of the ventilation system of a seasonal greenhouse at The Farm at South Mountain, Phoenix, Arizona. 8 year old image shot with Canon 40D and 100mm f/2.8 lens.