333 / 2024-02-29 16:40:41

Water balance model in R for water resources assessment in Malaysia

water balance,model,R,programming,tool,water resources

Thornthwaite and Mather daily water balance model is widely used in Malaysia for applications such as water availability assessment for ungauged or data-scarce catchments. The model is simple and involves minimal input parameters, which makes it suitable for preliminary analysis. An R script for the calculation of the water balance model was developed specifically for Malaysia. In this case study, we run the R script to model the inflow to Klang Gates dam reservoir, which serves the population of Kuala Lumpur, the capital city of Malaysia. The parameters required by the water balance model as input are daily rainfall data, potential evapotranspiration, water holding capacity, recession constant, direct runoff rate, available water for runoff, and catchment area. After setting the input parameters, the user can run the script to the end, which will generate output files. The output files include graphical plots of monthly and annual rainfall, monthly and annual runoff, and a flow duration curve (FDC), which is a conventional method to assess the water availability of a river catchment. The efficiency of the R script in replicating the workflow for Thornthwaite and Mather daily water balance model and its ability to generate the results significantly faster than a spreadsheet proves that the R-based approach provides a streamlined alternative for such tasks, besides ensuring reproducibility and transparency. The water balance model is applied for the assessment of surface water resources in Peninsular Malaysia. There is potential for extending the use of the model to include the assessment of other water balance components such as potential evapotranspiration and groundwater recharge across diverse temporal scales.