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Drainage mills & wind power Decorative motifs found in Norfolk churches suggest that windmills for grinding corn have been used in this area since the fourteenth century. A fine example of a later style of corn mill can be found at Sutton (TG383242). There is also another type of windmill seen in Norfolk which were built to drain marshes. These drainage mills (or windpumps) were erected on the Broads from the mid eighteenth century onwards. It is likely that drainage mills were originally designed and first used in Holland. In the thirteenth century much of the marshland area of the Broads could only be used for grazing during the summer months when the area was not flooded. At this time sea levels were rising and flooding became more frequent. Dykes were dug and embankments built to protect the grazing marshes and later when this was no longer sufficient, drainage mills were built. These wind powered drainage mills pumped water from marshes into dykes which was then pumped into the rivers. The drainage mills all comprise sails with a mechanism to turn the sails into the wind (a fantail or tail pole) and a mechanism to pump water (scoop wheel, plunger pump, or turbine). The mills transfer power from the turning sails through two sets of gears to an internal shaft. These shafts usually powered scoop wheels which scoop up collected water from low lying dykes and deposit it into higher level rivers which transported the water out to sea at Great Yarmouth. Later mills were often fitted with centrifugal pumps, known as turbines, which lifted water in a similar way to the effect of stirring a cup of tea very quickly. During the 1800s, 240 drainage mills were dotted throughout the Broads, 74 of which remain today, although most are derelict. Mills at Horsey (TG457222) and Berney Arms (TG465050) can be investigated in depth as they are open to visitors. Around the How Hill estate you can see three very different styles of drainage mill (a trestle mill, a hollow post mill and the more common tower mill) each with interesting names: Clayrack (TG369193), Turf Fen (TG369188) and Boardman’s (TG369192). Both Clayrack and Turf Fen are named after the land they are sited on, often mills take the name of either the owner of the marsh or the marshman or millman who looked after them, examples in Broadland being High’s Mill (TG457072), Hobbs’ Mill (TG347163) and Howard’s Mill (TG462072). Clayrack is a very special drainage mill because it is one of only two ‘Hollow Post’ drainage mills left in the Broads and the only one fitted with a scoop wheel. Most remaining drainage mills have a brick tower. In 1981 Clayrack Mill stood 4km away from its current position on Ranworth Marshes (TG363153). It was badly in need of restoration but Ranworth hosts many nesting birds vulnerable to disturbance so it had to be removed. Happily it was reconstructed in its current How Hill location and can occasionally be seen working to drain the marshes. Boardman’s Mill (or Skeleton Mill) is one of only three ‘Trestle’ mills left in the broads (the others are at Horning TG 344175 and St Olaves TM459995). The mill was built in 1897 by a local millwright from Ludham (TG389184) named Dan England. The trestle mills were a later and less expensive alternative to the brick tower mills but their largely timber construction has meant that like the hollow-post mills, few now survive. Boardman’s mill was also originally fitted with a scoopwheel but this was later replaced by a turbine pump. The mill stopped working in 1938 when it was blown over in a gale. Turf Fen is a typical brick tower mill, built in 1875. This mill has a special feature in that it has twin scoopwheels (not yet restored), with a choice of high or low gears, rather than the usual one, to provide additional power. The mill was used to drain Reedham Marsh (TG366194) until the marsh was no longer used for grazing cattle in the 1920s. Due to the efficient drainage of marshes grazing became more extensive from the mid-18th century onwards. Drained marshes contain lots of nutrients and so the grazing was very lush. But during the nineteenth century wind powered mills were supplemented by steam powered pumps, often working side by side. Technology continued to develop and during the first part of the twentieth century diesel powered pumps started to replace wind powered drainage in the Broads; although some marshes were still drained by wind power until the 1950s. Diesel powered pumps were far more efficient at draining the marshes and peaty soil shrank as it got drier. As a result we see many areas of grazing marsh that are lower than the water level in the river, in the Horsey area the marshes are even lower than sea level. Today the marshes are still drained. It is very important to be able to manipulate water levels for agriculture, reed cutting and nature conservation. The pumps used to do this drainage are today powered by electricity. People living in today’s society in the UK use more electrical appliances than ever before which means that large amounts of electricity need to be generated to cope with demand. Most electrical generation in the UK is done by burning fossil fuels which results in harmful carbon emissions that are causing global warming. There are alternative ways of generating electricity which do not deplete the world’s scarce supply of oil, gas and coal. There are several renewable sources of energy which use resources that will never run out, such as hydro (water), solar (sun) and wind power. Generators inside wind turbines change wind energy into electrical energy. Wind is a free source of energy and it causes much less pollution that other forms of electricity generation such as gas, oil or coal and nuclear power. Wind farms take up very little ground space and the areas in between the turbines can be utilised to graze animals. However, installing wind turbines can be costly, large amounts of materials can be used during their construction and some people consider wind turbines to be a blot on the landscape. Some residents at Martham (TG455180) have also raised concern over the noise pollution wind turbines cause and the interference with their television reception they have caused. Conservation organisations such as the RSPB have raised objections to wind turbines because of the threat they pose to nesting colonies or migrating birds. The USA, Denmark and Germany are all big producers of wind energy. In many parts of the world high technology wind turbines such as those at Martham are too expensive to be widely used. Different technologies are being investigated, whereby wind turbines can be built cheaply and easily from everyday materials, to enable developing countries to harness the wind as a source of power. The Broads Authority is keen to support developments for the generation of electricity from renewable sources. At Somerton there are already two separate wind power developments. The first is the Somerton Wind Turbine (TG468192). This turbine was built in 2000. The single turbine stands 65 metres tall and each of it’s blades are 33m long. The energy it produces is enough to supply 1400 homes and it provides 5% of Great Yarmouth’s electricity requirements. The second development is Blood Hill (TG477190) which consists of 10 turbines built in 1992. Each turbine is 30m high with blades measuring 13m. Together the 10 turbines produce enough electricity to power 1400 homes.
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