2006 Annual Report 4d.Progress report. This report serves to document research conducted under a specific cooperative agreement between the Agriculture Research Service and the University of California, Riverside, to provide assistance in completing objectives associated with parent project 5310-61000-009-00D, Decision Support Tools and Databases for Optimal Management of Chemically-Affected Soils, and projects 5310-61000-009-05R, Model Abstraction Techniques for Soil Water Flow and Transport, and 5310-61000-009-07T, Technology Transfer of Computer Software for Modeling Subsurface Contaminate Transport. Additional details of the research can be found in the reports for those projects. Research during FY 2006 produced several improvements in the windows-based HYDRUS software packages for predicting water, heat and solute movement in soils and groundwater. A fully three dimensional version of the code was released (HYDRUS-3D) which includes a sophisticated graphical user interface that facilitates data entry and visualization. We also developed new capabilities for simulating the transport of emerging contaminants such as pathogens and pharmaceuticals. Additionally, we continued our development of model abstraction techniques that will permit the analysis of large experimental data sets through a hierarchy of process-based modules within HYDRUS. Lastly, we continue work on improved pedotransfer functions using soil hydraulic and related field data. Previous work by ARS-Riverside in this area of research produced the public-domain software package, Rosetta, that may be used to rapidly estimate the hydraulic properties of unsaturated soils from soil texture and other readily available data using such pedotransfer functions. This software, which can be downloaded from the Salinity Laboratory's web site is being used by a large number of scientists, engineers, and soil and groundwater professionals dealing with water and pollutant movement in the subsurface.