Method Description

• Step 1 - in this section you can download the MS Excel template. Please do not cancel the headers reported.
• Step 2 - copy your data in the template and load it with the button "Select data file and upload". Here you have to insert also the Latitude of your study area following the table here, the runoff coefficient (in percentage) and the temperature (°C) for which the precipitation falls in rainfall form or snowfall form. You can chose to run the program for the entire record you upload (month by month) or calculate the water balance for a mean annual hydrological year (the input is the same, that is the mean monthly temperature and precipitation).
• Step 3 - even if we required your email, the program is completely free but it is necessary to receive the results.

The Thornthwaite-Mather water balance (Thornthwaite & Mather, 1955; Thornthwaite & Mather, 1957) uses an accounting procedure to analyze the allocation of water among various components of the hydrologic system. Inputs/outputs to/from the model are:

We recently pubished a paper; if you use the app please cite our work: Water Balance Computation: Comparison of Applications in Two European Watersheds. Hydrology 2021, 8, 34. https://doi.org/10.3390/hydrology8010034

INPUTS

• P = monthly precipitation (mm)
• Tm = mean monthly temperature (°C)
• LAT = latitude (°)
• SM = soil moisture storage capacity value (mm)
• beta = dimensionless runoff coefficient (%)
• SRT = snowfall rainfall threshold (°C)

OUTPUTS

• PET = monthly potential evapotranspiration (mm)
• delta = P-PET (mm)
• AET = monthly actual evapotranspiration (mm)
• ST = monthly soil moisture (mm)
• S = monthly water surplus (mm)
• RO = monthly runoff (mm)
• RES = dynamic water storage available for the next month (mm)
• SMRO = monthly snow melt runoff (mm)
• TOT RO = monthly total runoff (mm)