A Workflow for Soil and Water Assessment Tool (SWAT+) hydrological simulations with Land Use Land Cover Change scenario + Source-to-Sea interactions

This workflow applies the Soil and Water Assessment Tool (SWAT+) to simulate streamflow and temperature variations under a Land Use and Land Cover (LULC) change scenario. The workflow outputs are specifically formatted to be directly connected as inputs to the Marine Modelling System Workflow in the AquaINFRA VRE. If there is no need to connect the outputs to the Marine Modelling System, or if you wish to replicate the workflow using other SWAT+ output variables (e.g., evapotranspiration, sediment load, or nutrients), please use the following alternative workflow, which provides more flexible output-processing tools: https://aqua.usegalaxy.eu/u/amanda_batlle/w/aquainfra-la-tordera-spain-lulcc-scenario-qsliteimport. For SWAT2012 model please use: https://aqua.usegalaxy.eu/u/amanda_batlle/w/aquainfra-swat2012-vantaanjoki-river-water-quality-simulation. Designed for the AquaINFRA Mediterranean Use Case – Inland Model, the workflow ingests the TxtInOut directory from a calibrated SWAT+ model of the La Tordera Watershed (https://doi.org/10.23728/b2share.am3bh-05a34). It then performs two simulations: a baseline using the original LULC values for each Hydrological Response Unit (HRU), and a second with a LULC change scenario. This workflow has set the swat-simulation tool to generate daily flow out and temperature for the time frame between 2016 and 2020 (with 2 warmup years) for La Tordera watershed under a LULC change scenario, but can be adapted to allow the execution of any SWAT model by providing the corresponding TxtInOut folder and a suitable csv file to generate LULC changes to the watershed HRU. Visit toolbox documentation for more information on how to introduce different variables, time steps, time frames, or how to include parameter calibration (https://doi.org/10.23728/b2share.jpck1-sya68). Input Data 1. Text file containing the URL to the TxtInOut directory for the La Tordera SWAT+ model, calibrated for water quantity over 2000–2022. 2. Text file containing the URL to the CSV listing LULC-HRU changes to generate a scenario. Workflow Components The workflow consists of three main steps: SWAT+ simulation runs, LULC change processing, and output processing to connect to the Marine Modelling System Workflow and to generate visualisations. 1. SWAT Model LULC Update — Updates the `hru-data.hru` file within the TxtInOut directory using the provided CSV, which maps LULC changes to specific HRU IDs. This produces an updated TxtInOut directory in which HRU areas match the baseline, but LULC changes values. 2. SWAT+ Simulation — Runs the SWAT+ model to generate streamflow and temperature at the river mouth for both the baseline model and the projected LULC scenario. 3. Marine Modelling System Connection — Converts raw model outputs into two clean `.txt` files (one per scenario) with standardized date formats. Columns: `Date-time`, `Flow (m³/s)`, `Temperature (°C)`. These outputs can be connected directly to the Marine Modelling System as inputs. 5. Data Merge — Combines the two post-processed outputs into a single tabular dataset. Columns: `Date-time`, `Baseline Flow (m³/s)`, `Baseline Temperature (°C)`, `LULC Scenario Flow (m³/s)`, `LULC Scenario Temperature (°C)`. 6. (Optional) Interactive Visualization in Galaxy — Use Galaxy tool to generate a line plot comparing streamflow outputs between the baseline and LULC-change scenarios. Outputs 1. Baseline model output, formatted for the Marine Modelling System. 2. LULC scenario model output, formatted for the Marine Modelling System. 3. Merged tabular dataset combining both scenario outputs, ready for interactive comparative plotting plotting. How to Run the Workflow step-by-step 1. Prepare a `.txt` file containing the URL link for each of the input datasets. 2. Open the workflow and import it into your "My Workflows" in the Galaxy Virtual Research Environment (VRE). 3. Run the workflow, uploading the two `.txt` files created in step 1 as inputs, then press Run Workflow. 4. The model will run automatically (estimated run time: 12 minutes) and generate three outputs. 5. Use Combined_output_for_plotting output to visualize the combined outputs. Use swatplus_LULCscenario__MarineModelConnection, and swatplus_Baseline_MarineModelConnection. as inputs for the Marine Modelling System Workflow.