Reducing the sampling frequency of groundwater monitoring wells

A methodology for selecting sampling frequencies in environmental research that focuses on statistical thinking and brings considerable cost savings is described. The aim is to reduce sampling costs without jeopardizing information needed for decision making. It was applied to a 1992 benchmark volatile organic compound data set from 296 wells at the main site of the Lawrence Livermore National Laboratory, while a variant was used on data from groundwater monitoring wells at the Savannah River site. An overall schedule reduction of 30% was achieved in the required number of samples per year, while annual cost savings amounted to about $1.8 million.