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The Thames Tideway scheme is a proposed tunnel running mostly under the River Thames through central London, intended to provide storage and conveyance of combined raw sewage and rainwater discharges that currently overflow into the river. On 12 September 2014, the UK Government approved the plans, overriding some of the findings of the Planning Inspectorate.〔(【引用サイトリンク】url=http://cleanthames.org/2014/09/14/more-on-the-governments-summary-dismissal-of-the-planning-inspectorates-recommendations/ )〕 The decision has given rise to at least three Judicial Reviews.〔(【引用サイトリンク】url=http://www.bbc.co.uk/news/uk-england-london-29838239 )〕〔(【引用サイトリンク】url=http://www.bdb-law.co.uk/news-and-views/blogs/planning-act-2008/2014/november/589-walney-wind-farm-gets-consent-as-a160-beats-records#Other%20News/ )〕 The Thames Water project involves construction of a tunnel (the Thames Tideway Tunnel) running from Acton in the west of London through to Abbey Mills in the east, controlling 34 of the most polluting combined sewer overflows (CSOs) via transfer tunnels along the way or system modifications. The captured sewage will then be transferred to Beckton Sewage Treatment Works (currently being upgraded to increase capacity) via the Lee Tunnel (already under construction) for treatment before being released. The main tunnel will be approximately long and have an internal diameter of . It will run through the centre of London, mostly under the River Thames, at a depth of in the west through to in the east. Once constructed the system is expected to reduce the number of overflow events to a maximum of four per CSO per year at time of commissioning, increasing gradually due to effects of climate change and population growth.〔("Thames Tunnel Needs Report" ), section 5.3.4, Thames Water, Summer 2010.〕 Starting in 2016, construction of the Thames Tideway Tunnel would take seven to eight years. Its current planned target completion date is 2023.〔(Green Light for examination of Thames Tideway Tunnel Proposal ). Thames Water. 2013-03-27〕 The current estimate of its capital cost - excluding unknown financing costs and ongoing operations and maintenance costs - is £4.2 billion in 2012 prices.〔http://documents.scribd.com.s3.amazonaws.com/docs/tm71rgr0g19vbzf.pdf?t=1322490260〕 The budget for the scheme has steadily increased since it was first put forward - for example, the stated budget in 2004 was estimated at £1.7bn, which included the Lee Tunnel and sewage treatment works upgrade costs. In the words of the Consumer Council for Water: ''"The estimated cost of the project has escalated, from £1.7bn in 2004 (including Lee Tunnel and sewage treatment works (STW) costs) to £2.2bn in 2007 (also including Lee Tunnel and STW costs) to £3.6bn now for the shorter Thames Tunnel as far as Abbey Mills, plus some £1bn for the Lee Tunnel and upgrade of works at Beckton. The total costs of all the Tideway schemes have therefore increased from £1.7bn six years ago to £4.6bn today (all costs at relevant year prices). There is no guarantee that the current estimate will not be subject to further escalation."''〔("Thames Water's Thames Tunnel Consultation" ). Consumer Council for Water. January 2011.〕 Less than a year after this writing, a further £500m was added to the estimate.〔("Super-sewer’s price rises £500m" ). Financial Times. 2011-11-03. Retrieved 2013-07-30〕 ==Background== Built between 1859 and 1865, Sir Joseph Bazalgette's original London sewerage system was designed to capture both rainwater run-off and the sewage produced by four million people. As a fail-safe, to prevent sewage backing up and flooding people's homes, Bazalgette's system has the ability to overflow into the River Thames via 57 combined sewer overflows (CSO) along the banks of the river. Today, the population of London is an estimated eight million and Thames Water says that the current system lacks the necessary capacity. Bazalgette's original system does not serve all of these eight million people, as areas in outer London, built later, were provided with separate sewerage and rainwater infrastructure. Overflows have become more and more common and now occur on average 50 times a year.〔http://www.ccwater.org.uk/upload/pdf/London_tideway.pdf〕 These discharges, of combined raw sewage and rainwater, need to be reduced to comply with the EU's Waste Water Treatment Directive (UWWTD) and to improve the ecology of the river. An estimated total of some , or 39 million tonnes, of storm sewage enters the river in a typical year.〔(Thames Water ''Needs report'' ) (Summer 2010) accessed: 16 January 2014〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Thames Tideway Scheme」の詳細全文を読む スポンサード リンク
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