ABSTRACT
Groundwater is defined as water contained in pores in soil and fissures in rock below the water table-effectively the surface where the porewater pressure is equal to atmospheric (1.3).
Groundwater is part of the natural hydrological cycle of movement of water as a result of precipitation, percolation and evaporation. The amount of water which can percolate through the ground or run off to the sea, rivers, etc. depends on topography, geology and vegetation. Groundwater levels and flow can cause instability of excavations and foundations by seepage, uplift and lateral pressure. Knowledge of groundwater conditions and soil and rock structure is therefore essential for the safe design and construction of foundations.
