The sluice controlled the drainage of of land, and when it was tide locked by water levels in the Nene, levels in the drain rose to above Ordnance Datum.
22.
For instance, the Prins Alexander Polder in the northeast of Rotterdam extends below sea level, or rather below Normaal Amsterdams Peil ( NAP ) or'Amsterdam Ordnance Datum '.
23.
The levels are regulated between 12.45 metres to 12.6 metres above Ordnance Datum, as defined in the Lough Neagh ( Levels ) Scheme 1955 ( as amended ).
24.
At the highest point on Walton Hill, which reaches above Ordnance datum ( mean sea level ), It forms the starting point for the long footpath known as the Polden Way.
25.
The "'Black Mountain transmitting station "'is a broadcasting and telecommunications facility, situated on land above Ordnance Datum ( guyed steel lattice mast which is in height.
26.
In 1986 the East Beach was artificially raised with extra shingle to a height of above Ordnance Datum; subsequent management by the Environment Agency has involved regular monitoring and replenishment of this shingle barrier.
27.
The marking was formally presented on the 82nd birthday of Kaiser Wilhelm I . on 22 March 1879 . This point was derived from the Amsterdam Ordnance Datum and marked off 37 meters over zero.
28.
Shortly after 18 : 00 ( BST ) 26 December, the monitoring station at Collingham for the River Wharfe reached a record high of above ordnance datum ( previous high level was AOD ).
29.
The hills which rise to above Ordnance datum ( mean sea level ) are made up of limestone, rheatic clay and Keuper marl covered with calcareous grassland, scrubland and youth hostel in Somerset.
30.
Within the boundaries of this municipality lies the lowest point of the Netherlands : 6.76 m ( 22.2 ft ) below Amsterdam Ordnance Datum ( mean summer sea level in Amsterdam ).
