Groundwater Drawdown Related Settlement and Pump Text Interpretation

Settlement associated with groundwater drawdown can be an important design factor for construction below the watertable. As a result, prediction of the extent and magnitude of groundwater drawdown is an essential part of the evaluation of potential impacts of deep structures. Pump test analysis is routinely employed to for assessment of hydraulic properties of aquifer units affected by deep excavation. Interpretation of pump tests makes use of the rate of groundwater extraction and the drawdown measured in the pumping bores and at other locations. Settlement is not usually considered during interpretation of pump tests. This paper discusses settlement due to dewatering and proposes use of settlement monitoring for interpretation of pump test results.