Debris flood, a major hazard in mountainous areas, is characterized as a mixture of water and sediment primarily driven by hydrological processes. However, the relationship between water and sediment remains unclear, and accurately describing the hydrograph of such flows continues to pose significant challenges due to the complexity of the debris flood process and the difficulties associated with field monitoring. This study utilizes real-time monitoring data from the Ergou catchment, China, combined with hydrological modeling, to investigate the relationship between water discharge and sediment influx during debris floods. Our results show that the instantaneous sediment flux exhibits considerable fluctuations at real-time resolution, consistent with original measurements, following a Pareto distribution. As the temporal interval increases to half, one, and 5 min, the relationship gradually emerges as an exponential function, eventually revealing a near-linear correlation between the total volumes of sediment and water throughout the flood. Based on these observations, we propose a framework integrating hydrological simulation of water flow, sediment-water relationships to estimate the continuous hydrograph of debris floods. The errors for the peak discharge and the total volumes decrease with lower temporal resolution. Specifically, the errors of peak discharge at the 2-min resolution are confined within the ranges of [-26%, 6%]. The findings contribute to improve understanding of debris flood processes on a watershed scale.