SX4368 : Calstock Viaduct
taken 8 years ago, near to Calstock, Cornwall, England
The viaduct is 120 feet high with twelve 60 feet wide arches, and a further small arch in the Calstock abutment. Three of the piers stand in the River Tamar, which is tidal at this point and has a minimum clearance at high tide of 110 feet.
It was built between 1904 and 1907 by John Lang of Liskeard using 11,148 concrete blocks. These were cast in a temporary yard on the Devon bank opposite the village. The engineers were Richard Church and WR Galbraith.
It is a Grade II* listed structure.
The Tamar (Cornish: Dowr Tamar) is in south west England, it forms most of the border between Devon and Cornwall.
The Tamar's source is 3 miles from the north Cornish coast, but it flows southward and its course runs across the peninsula to the south coast. The total length of the river is 61 miles. At its mouth, the Tamar flows into the Hamoaze before entering Plymouth Sound. Tributaries of the river include the rivers Inny, Ottery, Kensey and Lynher (or St Germans River) on the Cornish side, and the Deer and Tavy on the Devon side.
Listed buildings and structures are officially designated as being of special architectural, historical or cultural significance. There are over half a million listed structures in the United Kingdom, covered by around 375,000 listings.
Listed status is more commonly associated with buildings or groups of buildings, however it can cover many other structures, including bridges, headstones, steps, ponds, monuments, walls, phone boxes, wrecks, parks, and heritage sites, and in more recent times a road crossing (Abbey Road) and graffiti art (Banksy 'Spy-booth') have been included.
In England and Wales there are three main listing designations;
Grade I (2.5%) - exceptional interest, sometimes considered to be internationally important.
Grade II* (5.5%) - particularly important buildings of more than special interest.
Grade II (92%) - nationally important and of special interest.
There are also locally listed structures (at the discretion of local authorities) using A, B and C designations.
In Scotland three classifications are also used but the criteria are different. There are around 47,500 Listed buildings.
Category A (8%)- generally equivalent to Grade I and II* in England and Wales
Category B (51%)- this appears generally to cover the ground of Grade II, recognising national importance.
Category C (41%)- buildings of local importance, probably with some overlap with English Grade II.
In Northern Ireland the criteria are similar to Scotland, but the classifications are:
Grade A (2.3%)
Grade B+ (4.7%)
Grade B (93%)
Read more at Wikipedia Link