Rehabilitation of the Parongking River in Pangasinan, Philippines

Parongking River, located in the Municipality of Calasiao and the City of Dagupan in Pangasinan [Philippines], was declared as biologically dead river because of its contamination of both domestic and industrial wastes, and there was an urgent need to save and revive the dying river. Hence, this study was conducted to assess the status of the Parongking River before and after its rehabilitation. Specifically, the study aimed to (1) describe the different activities undertaken during the rehabilitation of the Parongking River and (2) to determine and compare the concentration of important physico-chemical and biological/microbiological parameters of the river water before and after its rehabilitations. This was done by conducting a personal interview with key persons and by conducting an on-site and laboratory water quality analyses before and after the rehabilitation. The rehabilitation of the Parongking River started by conducting water quality analyses of the river and presented the result to various stockholders in an environmental symposium and by conducting a series of multi-sectoral meetings and consultations to come up with an approved proposal to revive the dying river. The launching of the river's rehabilitation marked the start of the cleaning and dredging the river by the community and various organizations. Results showed that the river's rehabilitation significantly improved the water quality conditions of the river making it flowing, clean and suitable for the growth of various species of plankton. The water depth and temperature were significantly increased in depth and range, respectively, while the turbidity, total suspended solids, ammonia and phosphate concentrations and the level of total and fecal coliform were significantly decreased to desirable levels. No significant increase on the density of phytoplankton was observed, however, a more diverse species of phytoplankton was observed after the rehabilitation. A significant increase on zooplankton density was also observed after the rehabilitation indicating the revival of the river to support aquatic life.