Predicting Ground-Water Response to Precipitation

High ground-water levels are a principal cause of slope instability and of significance in other geotechnical engineering problems. A methodology has been developed, and is described in this paper, for predicting the fluctuation of ground-water levels as a function of precipitation. The approximate method uses measured characteristics of the site or region and a short period of calibration from a well record. The linkage of precipitation to ground-water fluctuation can be used in either deterministic or probabilistic methods. The new methodology has been tested by application in several different geological and climatological areas. Based on these field studies, the sensitivity of the methodology to calibration period, aquifer response time, evapotranspiration and other characteristics has been evaluated. The overall conclusion of the work has been a demonstration that the fluctuation of ground-water levels, including extreme values, can be predicted with sufficient accuracy for many design and analysis problems.