The researchers studied how rainfall leads to runoff in the Kolong River Basin in Assam, India. They used a method called NRCS-Curve Number along with satellite images to estimate the amount of runoff based on rainfall data from 2004 to 2018. By analyzing the runoff frequency, they were able to predict the likelihood of different runoff levels occurring. The NRCS-Curve Number method considers factors like soil type, land use, and moisture levels to calculate runoff volume. The study found that this approach can help in managing floods and other water-related issues in the region.