Trend‐Surface Analysis of Ground‐Water Fluctuations

Abstract

As round‐water research is accelerated and basic data on aquifer parameters become more abundant, a statistical approach to evaluation of the ground‐water regimen becomes increasingly useful. One such statistical technique is the fitting of polynomial trend‐surfaces to ground‐water levels. Barcholomew County, Indiana was chosen as a test site to derive techniques which could give additional guidance in the selection of areas suitable for the development of future ground‐water resources. Trend‐surface maps and maps of the deviations from the trend‐surfaces were prepared from water‐level data and evaluated to establish their relationships with the hydrogeologic regimen. A field‐testing program was carried out to evaluate aquifer parameters. On the basis of the results obtained from these studies, the following conclusions were drawn: A mathematically fitted surface may be considered to approximate the water‐table or piezomecric surface, and will be sensitive to fluctuations in the ground‐water reservoir. The anomalous areas of the trend‐surface represent local effects superimposed on the regional base and may be explained by a particular set of geologic, hydrologie or man‐made conditions. From these conclusions, it appears that trend‐surface analysis provides a rapid, inexpensive method of delineating attractive areas for detailed ground‐water investigations. Copyright © 1970, Wiley Blackwell. All rights reserved