The Biophysical Toolbox: a Biophysical Modelling Tool Developed within the IWRAM-DSS

With rapid intensification of agricultural catchments in northern Thailand a suite of environmental issues have surfaced. The Integrated Water Resources Assessment and Management (IWRAM) project was instigated in response to these issues. The project developed a Decision Support System for the exploration of biophysical and socio-economic impacts of water resources use option. The IWRAM-DSS is comprised of a 'Biophysical Toolbox' that can be implemented alone or an 'Integrated Toolbox' that links socioeconomic models with the biophysical toolbox to explore economic trade-offs and impacts of various scenarios. The Biophysical Toolbox is comprised of three modules - the CATCHCROP crop model, a hydrologic module based upon the IHACRES rainfall-runoff model, and a Universal Soil Loss Equation (USLE) approach modified to suit conditions in northern Thailand. This working paper describes and implements the Fortran 77 version of the Biophysical Toolkit developed jointly by Dr. Barry Croke and Wendy Merritt. A Java version of the model has been coded by Dr. Claude Dietrich and Nick Ardlie, however this version has not been linked with the economic model as part of the fully integrated IWRAM-DSS.