ASEANO Project Report: Mapping of Sources and Concentration of Plastic Waste in the Imus River Watershed


Tuesday, April 19, 2022




Only Available Online


The sources of plastic wastes and areas of expected high levels of plastic waste generation were mapped in the Imus River Watershed in the Province of Cavite, in the Philippines. Different sources of plastic waste were identified, and used to estimate the magnitude of plastic waste generation. Information on the major sources of plastic waste were obtained from the 10-Year Solid Waste Management Plan of the seven cities and municipalities located within the boundaries of the watershed. Remote sensing technology was used to identify the coordinates of different potential sources. For higher resolution, Google Imagery was used in preparing base maps which were imported and georeferenced in ArcMap. A 7-day waste characterization study in three selected barangays was conducted to determine the average amount of plastic waste generated per household. This data served as inputs for a hotspot analysis in ArcGIS to identify plastic waste generation hotspots within the watershed. The Imus River system traverses seven cities and municipalities that include parts of Tagaytay City, Silang, and Amadeo in the upland areas, a large part of the densely populated and urbanized cities of Dasmariñas and Imus City in the central hilly areas, and portions of the lowland City of Bacoor and the coastal Municipality of Kawit. It has a total drainage area of 11,259.80 hectares. A total of 222 barangay communities were identified within the boundaries of the watershed with a total population of 1,351,057. The major sources of waste in the watershed were primarily households, followed by commercial, institutional, and industrial establishments. The total number of commercial, institutional, and industrial establishments identified was 778, and a total of 54 waste storage facilities were found in the watershed. From the 7-day characterization study in three selected barangay communities, an average of 113.03 kg of plastics was generated daily by the households in Barangay Burol 1, Dasmariñas City; 9.17 kg/day in Barangay Mabolo 1, Bacoor City; and 29.29 kg/day in Barangay Maitim 2nd Central, Tagaytay City. An average of 0.17 Kg/day per household of plastics were generated in the watershed and 0.05 Kg/day per capita.  A cluster of high plastic waste generating barangays was identified in Dasmariñas City, where various tributaries of the Imus River converge. This combination is likely to create a significant hotspot for waste leakage. Clusters of low plastic waste generating barangays were identified in parts of Imus, Kawit, and Bacoor. These cold spots should not be ignored, as increasing plastic waste generation could exceed capacity and push them into future leakage hotspots.