SWAT+ model setup verification tool: SWATdoctR

The Soil and Water Assessment Tool (SWAT) is applied worldwide for modeling basin-scale processes. Its latest version (SWAT+) adds new capabilities to the tool, and collectively with increasing computational power and availability of public datasets expands model complexity as well as provides pathways for serious errors in the model setup process. These models are used to run scenarios to support decision-making processes, hence undetected faults can have a substantial socio-economic and environmental impact. We propose a 5-step SWAT+ model setup verification workflow assessing the soundness of processes related to weather, water balance, management, plant growth, point source and tile drain flows. We developed an R package, called SWATdoctR, which guides the user through the model setup verification process, allowing the identification of typical, but repeatedly overlooked, issues. The workflow and the functionality of the tool is demonstrated in 4 SWAT+ setups in different catchments, at various stages of model setup.