Estimation of the Sediment Discharge of Marikina River Basin using Hydrologic Modeling System (HEC-HMS)

Natural calamities have intensified through the years and have brought about damage to life and property across the world. Urban development has also been rapid in many communities due to the continuous increase in population thus affecting watersheds and altering their hydrologic response leading to events such as flooding. Hydrologic modeling as a tool for representing real-world scenarios is now being used as a way for engineers and managers to strategize best management practices in watershed preservation. This paper aimed to estimate the sediment discharge of Marikina River Basin during a storm event using the Hydraulic Engineering Center - Hydrologic Modeling System (HEC-HMS) software. The Digital Elevation Model of the study area was processed using Geographical Information System (GIS) to delineate the watershed that was used in setting up the hydrology model. Model parameters were calibrated, and fitness of the model was based on statistical ratings of Nash-Sutcliffe Efficiency (NSE), Percent Bias (PBIAS), and Pearson's Coefficient (R²). A good model performance was achieved recording an NSE, R2, and PBIAS of 0.65, 0.76, and 12.54% respectively. Using the calibrated and validated HEC-HMS model, the sedimentation feature was enabled and used to compute the sediment discharges during the 2016 Habagat storm event. Upstream subbasin sediment yield was computed to reach about 10,248.80 tonnes while for the downstream subbasin, a sediment load of 963.3 tonnes was recorded. The capability of HEC-HMS to calculate sediment discharge at a subbasin level can be used as a tool in managing watersheds to balance future development and mitigating the possible threats of anthropogenic activities and extreme weather events to the community.