Statistical quality control and geostatistical analyses of 2005 Kansas High Plains aquifer water level measurements

The High Plains aquifer is the primary source of water for western and south central Kansas. The Kansas Geological Survey (KGS) and the Kansas Department of Agriculture's Division of Water Resources (DWR) measure High Plains Aquifer water levels on an annual basis in a network of over 1300 wells, in order to assist in the management of this vital resource. The measurements and additional information regarding the wells are stored in the KGS's Water Information Storage and Retrieval Database (WIZARD), which is accessible to the public through convenient web forms. We present the results of the statistical quality control and geostatistical analyses of the winter 2005 (December 2004 - February 2005) measurement campaign. The quality control analysis consists of an analysis of variance (ANOVA) procedure performed in S-Plus. We have performed the geostatistical analyses using a combination of the S-Plus SpatialStats add-in and ArcGIS. The quality control analysis confirms the reliability of the measurements and the summary statistics and geostatistical analyses reveal a marked decrease in the water level decline rate over 2004 compared to previous years.