Influence of hydrological runoff and catchment characteristics on accumulation floatable litter load in gross pollutant trap (GPT)

The accumulation of floatable litter load captured in gross pollutant trap (GPT) due to the hydrological runoff has become challenging due to rapid development and alteration of land use changes. The application of soil conservation service curve number (SCS-CN) method has been widely used to estimate the direct runoff from the given rainfall especially when there is no runoff measured within the catchment. The results found that there was enormous variation on floatable litter load between different months and individual GPT. There was a high accumulation of floatable litter load on August 2015 with 495 kg/month and at K17 with 510 kg. Both of these conditions was significantly influenced by rainfall depth, hydrological parameters such as initial abstraction, potential maximum retention, and average weighted curve number (CN aw ) values from different types of land use within their respective catchment area for individual GPT. Thus, the outcomes from this study can be very useful and beneficial for related government agencies and various stakeholders in ameliorating this critical and challenging environmental issue in terms of operation and management; technical operation; the selection of GPT prior to installation in other areas including the design, costs and maintenance.