Pi-VAT: A web-based visualization tool for decision support using spatially complex water quality model outputs

•Pi-VAT is a post-processing, interactive visualization, and analysis tool.•Simple implementation to facilitate ‘what-if’ analysis using WEPP and SWAT outputs.•Suitable for assessing areas for targeted management.•Synthesize and visualize multiple watersheds and scenarios.•An approach to address the need for integrating extensive outputs from process-based models into decision support tools.