Abstract In recent years, watershed modelers have put increasing emphasis on capturing the interaction of landscape hydrologic processes instead of focusing on streamflow at the watershed outlet alone. Understanding the hydrologic connectivity between landscape elements is important to explain the hydrologic response of a watershed to rainfall events. The Soil and Water Assessment Tool+ (SWAT+) is a new version of SWAT with improved runoff routing capabilities. Subbasins may be divided into landscape units (LSUs), e.g., upland areas and floodplains, and flow can be routed between these LSUs. We ran three scenarios representing different extents of connectivity between uplands, floodplains, and streams. In the first and second scenarios, the ratio of channelized flow from the upland to the stream and sheet flow from the upland to the floodplain was 70/30 and 30/70, respectively, for all upland/floodplain pairs. In the third scenario, the ratio was calculated for each upland/floodplain pair based on the upland/floodplain area ratio. Results indicate differences in streamflow were small, but the relative importance of flow components and upland areas and floodplains as sources of surface runoff changed. Also, the soil moisture in the floodplains was impacted. The third scenario was found to provide more realistic results than the other two. A realistic representation of connectivity in watershed models has important implications for the identification of pollution sources and sinks.
A Graphical User Interface (GUI) is regularly used to support model applications in catchment hydrological modelling software. A GUI is generally user-friendly for novice users but opens sources of irreproducible research. We illustrate that none of the 10 Soil and Water Assessment Tool (SWAT) models over the Upper Blue Nile can easily be reproduced. Scripted workflows provide the ability to reproduce model set-ups, but they may be less user-friendly especially to novice users. We present a software (SWAT + AW) that promotes reproducible SWAT + model studies while remaining user-friendly for both novice and expert users. SWAT + AW uses a configuration file to create models that are compatible with GUI. We applied the workflow to the Blue Nile catchment and show that it yields the same results the SWAT + GUI. We conclude that such user-friendly scripted workflows enhance reproducibility, transparency and reusability of hydrological models. The software is publicly available at https://github.com/VUB-HYDR/SWATPlus-AW.
(2008). Advances in ecohydrological modelling with SWAT—a review. Hydrological Sciences Journal: Vol. 53, Advances in ecohydrological modelling with SWAT, pp. 939-947.
