Performance Evaluation of Lumped Conceptual Rainfall-Runoff Genie Rural (GR) Hydrological Models for Streamflow Simulation

Hydrological modeling is essential for water resources management, impact assessment and risk evaluation. From the point of view of water resources planning, estimation of runoff from a watershed is of great importance in most hydrological analysis. Due to the model’s complex structure and huge data requirement in semi-distributed or distributed models, nowadays lumped conceptual models are frequently used for operational applications because they represent and transform catchment scale rainfall-runoff in a simplified way. As a result, these models usually require less data and can be readily implemented. The present study uses package airGR which facilitate the daily versions of the GR lumped hydrological models, namely GR4J, GR5J and GR6J and compares their performance for streamflow simulation within RStudio interface. The Bharathapuzha river’s sub-basin in Kerala is selected for this study. The models are calibrated and validated using observed data of daily rainfall, and daily discharge and estimates of daily potential evapotranspiration for a period of 27 years (1987–2013). Daily potential evapotranspiration is estimated using FAO ET0 calculator (version 3.2). The performance of the model streamflow predictions is evaluated based on various statistical measures. Results of the analysis are presented and discussed.