This research examined how the Metolong Dam has affected nearby communities and the surrounding environment while supporting long-term development. The findings show that the dam has improved the water supply reliability, strengthened agricultural activities, and supported the production of renewable electricity. With water now available more consistently throughout the year, many farmers can irrigate their crops regularly rather than relying solely on seasonal rainfall. This has increased crop production and improved household food security. Reliable water access also enables farmers to plan their activities more effectively, supporting more stable livelihoods. Another key benefit is improved access to electricity. Many households now depend less on traditional energy sources such as firewood. This change has made daily life easier, especially for cooking, lighting, and using small appliances. Access to electricity has also created new opportunities for small businesses and local economic activities. Shops and service providers can now operate more efficiently, contributing to economic growth within the community. The study gathered data through interviews and discussions with community members, government officials, and environmental experts. It also reviewed official reports and related documents to understand the social, economic, and environmental impacts of the project. Although clear benefits were reported by participants, some concerns were raised about environmental disturbances and the relocation of households during construction. These concerns highlight the need for ongoing environmental monitoring and stronger community involvement in future development planning.