Dunkirk: Where History Happened. We visit 10 places connected with the remarkable evacuation of the British Expeditionary Force from northern France in 1940. This feature was first published in the April 2010 edition of BBC History Magazine. Tuesday 25th May 2010.
The seepage velocity is less than the actual flow rate of the liquid or gas in the pores because the fluid moves only through the portion of the cross-sectional area S that is occupied by the pores.
Equation (5.13) indicates that hzYjz{ is the increase in the effective pressure as the water. flows from the surface to a depth z. This increase in effective pressure due to the flow of water. through the pores of the soil is known as seepage pressure.