At the Battle of Flodden Field in 1513, the Scottish army occupied the high ridge in the distance. They had an advantage over the English who were where the memorial stands in the foreground. The Scots were defeated because they advanced down the hill and got stuck in the mud in the dip between the two ridges where their weapons were ill-suited. This is where the piezometric surface comes in.
A
piezometric surface is an imaginary line that shows where pressure would take water up to if it were totally free. Notice that this line coincides with the surface in the dip meaning that it would be marshy. The other two points where it coincides with the surface are a spring and a stream.
