If a well penetrates the confining layer, water will rise to this level, the piezometric level, the artesian equivalent of the water table . If the piezometric level is above ground level, the well discharges as a flowing well , artesian well, or a spring . The height of the water behind a dam . Various datums may be used and various pool height may be used, e.g., conservation pool , flood control pool , etc. The ratio of pore volume to total volume of the soil.
Sandy soils have large pores and a higher porosity than clays and other fine-grained soils.
Varies by season. Energy contained by fluid because of its pressure, usually expressed in a depth of fluid.