IMPROVING INFILTRATION MODELING FOR PAPUA’S SMALL WATERSHED BY USING RSTUDIO SOFTWARE ANALYSIS

Abstract

Eco-hydrological processes in watersheds are essential for policy development and social growth despite growing environmental concerns. These processes represent a dynamic interaction between the hydrological cycle and ecological elements, with infiltration as one of the important components. According to preliminary studies, the availability of infiltration rate data holds significant importance for irrigation planning, flood management, and water resource studies. Presently, there is a global decrease in hydrological data due to the abundance of water resources in Papua. Existing literature emphasizes the need to evaluate the Kostiakov and Green Ampt models in varied soil textures in Papua, particularly within small watersheds. Therefore, this research compared the performance of the two models on each soil texture using the Hydrological Soil Group classification. It also analyzed modifications for models with unsatisfactory performance through the use of RStudio software analysis with k-fold cross-validation. The results showed that the Green Ampt model performs better than the Kostiakov model for nine soil textures, with average performance values of 0.800 (R), 0.636 (NSE), and 0.588 (RSR). Although the Kostiakov model initially underperformed, it was enhanced to the Pristianto Model by integrating soil properties such as water content (w), porosity (n) and sand content (Sn). Further evaluation in other small watersheds is needed to confirm its robustness. In conclusion, this research filled hydrology data gaps in Papua, which resulted in an infiltration model tailored to the soil characteristics of small watersheds.