Uncertainty and Sensitivity Analysis of the Effective Implementation of Water Quality Improvement Programs for Citarum River, West Java, Indonesia

Pollution of rivers is a challenge for many countries. In the Citarum watershed, Indonesia, where pollution has been an emerging issue nationwide, many programs and policies have been set up. However, implementation of all the planned programs and the significance of their contributions toward water quality improvement of the Citarum River have not been analyzed. In this paper, we present original research on evaluating water quality programs planned to achieve outputs by using uncertainty and sensitivity analysis for a river. The essential inputs included: (1) key parameters, (2) priority planned programs, and (3) interrelationships between programs, parameters, and the level of successfulness of water quality control programs. The first and second inputs were prepared simultaneously using Principal Component Analysis (PCA) and Analytical Hierarchy Process (AHP). The latter was obtained using the Delphi method to obtain the related stakeholders’ opinions. Finally, we explore Monte Carlo simulation to analyze parameter uncertainty and sensitivity contributing to the program’s effectiveness. By implementing all the water quality control programs, the results showed that cadmium, BOD, and fecal coliform were the most affected parameters. In addition, the most effective programs to improve the pollution index were domestic waste, farming, solid waste, and water resource programs. If those programs were implemented collectively, the probability of reducing the pollution index was within a range 2.01–36.22% from the base case.