APPLICATION OF COUPLED HEC-HMS AND US EPA WASP FOR TRANSPORT MODELLING OF MERCURY IN THE MINING-IMPACTED AMBALANGA RIVER

This study provides a simulation of mercury (Hg) transport in water and sediments the mining-impacted Ambalanga River located Upper Agno Subbasin Philippines. The Hydrologic Engineering Center - Modeling System (HEC-HMS) Water Quality Analysis Simulation Program (WASP) US Environmental Protection Agency (EPA) were coupled to handle both hydrologic modelling total Hg processes, respectively, for 12 months year 2014. Watershed delineation from Digital Elevation Model, rainfall streamflow data local weather bureau, dam operational used develop hydrological model. calibrated HEC-HMS model satisfactorily simulated flow river its tributaries, which is then as an input subbasin was conceptually divided into 29 segments WASP represent column surface benthic sediment. Time-variable sediment load applied upstream River. Total concentration at five sampling locations along two measured 2014-2015, addition monitoring environmental bureau. gathered validate model, results show that it able reasonably simulate fate transport. showed downward trend downstream, while observed stabilize over time. further utilized come up with exceedance curves result river’s response different loading known point sources. derived determine maximum permissible identify pollution reduction measures rehabilitation.