The GroundWater Spatiotemporal Data Analysis Tool (GWSDAT) is a user friendly, open source, decision support tool for the analysis and reporting of groundwater monitoring data. Uniquely, GWSDAT applies a spatiotemporal model smoother for a more coherent and smooth interpretation of the interaction in spatial and time-series components of groundwater solute concentrations. Data entry is via a standardised Microsoft Excel input template whilst the underlying statistical modelling and graphical output are generated using the open source statistical program R. This paper describes in detail the various plotting options available and how the graphical user interface can be used for rapid, rigorous and interactive trend analysis with facilitated report generation. GWSDAT has been used extensively in the assessment of soil and groundwater conditions at Shell's downstream assets and the discussion section describes the benefits of its applied use. Finally, some consideration is given to possible future developments. GWSDAT (GroundWater Spatiotemporal Data Analysis Tool) Wayne R. Jones Shell Global Solutions (UK) (wayne.w.jones@shell.com) 2013 Standard PC Microsoft Windows (XP or later) Microsoft Office (Excel, Word and PowerPoint) and R (www.r-project.org) 13 MB www.claire.co.uk/GWSDAT Free under a GNU General Public License (www.gnu.org) agreement. User manual, example data sets, FAQ document, presentations and posters. 
A software tool for the spatiotemporal analysis and reporting of groundwater monitoring data