Interactive Declustering of Spatial Environmental Data for Geostatistical Analyses

Clustered sampling often results during environmental site investigations when localized areas are over-sampled due to specific concerns in those areas or due to monitoring programs focused on specific zones. An interactive, nearest-neighbor method for efficient spatial declustering has been developed as part of the ongoing monitoring and assessment of Cs-137 concentrations in soils at the Idaho National Laboratory (INL) site. Insitu field measurements of Cs-137 have been obtained with a field gamma-ray spectrometer using a sampling layout with points concentrated around several former nuclear processing facilities. The spatial declustering process allows for more useful and productive geostatistical studies focused on characterization of spatial dependence and subsequent spatial estimation to generate maps that depict Cs-137 concentrations across the site