4. REMOVAL OF WATER FROM EXCAVATIONS

When soil conditions are such that sides or base of the excavation remain stable, usually the least expensive method is to pump the water out. Plan for the correct pump and tankage capacity, or drainage (with the necessary Local Authority agreement). If, however, there is a possibility of instability of unsupported slopes or softening or heave of the bottom of the excavation, it is advisable to remove the water from the ground before it reaches the excavation by means of an external ground water lowering installation.

The resulting changes in ground water levels, and the re-established water levels afterwards, often cause tilting or settlement in adjacent structures.