Detail on Plate Laying
Rectangular aluminium plates, 5mm thick and measuring 200mm x 300mm were manufactured for this task. To account for changes in accretion/erosion parallel to the river flow, 3 plates were put in a row, approximately 1m apart. Where the mudflats were wide enough, it was necessary to take into account changes at right angles to the river flow. Therefore an extra plate was placed closer to the riverbank and another, closer to the water's edge, forming a cross shape. These plates were approximately 3 meters away from the central plate.
Laying of the 5 plates at Piddinghoe
They were buried 5 to 10cm under the mud and parallel to the surface, as most of the mudflats slope fairly steeply. To relocate the plates, bamboo sticks were placed in the top right hand corner, closest to the bank.
On a monthly basis, a skewer is pushed down through the mud until it reaches the accretion plate surface. This depth is then measured. Approximately 12 measurements are taken across the surface of each plate and an average is found. In this way, changes in the elevation of the mudflat are quantified.
These pages maintained by Martin Wingfield This section last updated 20/MAY/2003