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.

Water authorities in West Java, Indonesia have difficulties in implementing water improvement programs due to lack of tools for prioritisation of water-related issues and their respective programs. To facilitate more efficient management of the water resources, the West Java Water Sustainability Index (WJWSI) was recently developed. This paper outlines the tasks for developing WJWSI and highlights the results of its application in one of West Java catchments, Citarum catchment. The results showed that five out of the thirteen indicators and sub-indicators, namely ‘Water Availability, Water Quality, Education, Water Loss and Poverty’, had low sub-indices and thus had poor performances. Then, the sub-indices were aggregated using the geometric aggregation method to produce the final index. The results of the aggregation indicated that the overall condition of water resources in Citarum catchment was considered poor, with a final index value of 20.04. Based on the WJWSI application, recommendations are suggested to the relevant authorities in the Citarum catchment. It is expected that the implementation of these recommendations will improve the performance of these five indicators and sub-indicators from Poor to at least the next higher level of Poor–Medium, thus improving the value of the final index from 20.04 to 37.19.

The Cicatih River in the Cikembar sub-watershed, located in Sukabumi Regency, flows along the upstream of the Cikembar sub-watershed and Palabuhan Ratu Bay. For decades, the river has served as a vital water resource, catering to various needs such as domestic use, agriculture, livestock, fisheries, industry, mining, tourism, and hydroelectric power. Recently, the Sukabumi Regency Government made the pollution of coastal and river areas one of the priority issues on sustainable development initiatives for the Sukabumi Regency. This highlights the importance of managing the Cicatih River, one of the main rivers in the regency. This research aims to analyze the potential pollution loads in the Cikembar sub-watershed to the Cicatih River by assessing its water quality status and potential pollution loads from four main sectors: domestic, agricultural, livestock, and industrial. The water quality was calculated based on the Pollution Index method. The potential pollution load from different sources was analyzed using various emission factor calculations. For each pollutant source, the following parameters were analyzed: total suspended solids (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), Total-N (nitrogen), and Total-P (phosphorus). Results showed that the condition of the Cicatih River is slightly polluted. The parameter exceeding its maximum threshold is BOD. The largest contributor to the potential pollution load of BOD is the domestic sector (53%), while the agricultural sector is the least (2%). In the domestic sector, Bojongkembar Village is the largest contributor to the potential pollution load. The results of this analysis can be used to develop strategies for managing the overall Cikembar sub-watershed.

The Ciliwung River is the potential water source for the people of Jakarta and Bogor. Rapid urbanization and industrial development have sparked severe problems in the water resources of the Ciliwung River. The potential pollutants increase as the river flows through residential, business, and industrial areas, where drainage and sanitation infrastructure are worse. Water is naturally tagged with natural tracers, such as temperature, electrical conductivity, chemical constituents, and environmental water isotopes (δ²H and δ¹⁸O). These proved valuable tracers to identify the origin of the water. This research aims to trace the origin of the Ciliwung River water using a stable isotope approach and physical parameters. Research methods are field surveys, laboratory analysis, and analytical studies—sampling at 12 points of river water for a physical parameter and 5 points for stable isotopes. The research results show that the water origin of Ciliwung’s is rainwater. The stable isotopes in the upstream area are smaller than those in the upstream area experiencing enrichment. Factors leading to enrichment are inputs from anthropogenic activities to water bodies from household, agricultural, and industrial pollution. The results of this research are helpful for the government and academics in designing Ciliwung River conservation policies.

Cibodas Botanical Garden (CBG) is believed to have high environmental value for its function as conservation area and beautiful scenery. However, prior to this research, there is lack of economic valuation to determine the total value of CBG, including its environment. The local government, on the other hand, needs such environmental economic valuation to execute better decisions related to the CBG. This study aims at providing the mostly-needed economic valuation through the application of Travel Cost Method. The Travel Cost Method (TCM) is a method to calculate the economic value of products or services that do not own market value. This method utilises total cost of consumers who travel to certain places, preferably tourist destinations. The cost spent by consumers are considered as their willingness to pay (WTP) for the visited destination(s). In this study, TCM is used by preparing questionnaires for Cibodas visitors, analysing the results of the questionnaires, calculating the total economic value (TEV) of Cibodas, determining the consumer surplus, and proposing environmental programs at CBG. At the end, it was calculated that the TEV of Cibodas Botanical Garden is IDR113,072,532,700 with average WTP of the visitors IDR202,484 per visitor and the consumer surplus of IDR32,344 per visitor. Also, this study reveals that solid waste management improvement at CBG can be funded by potential income from the consumer surplus.