The Chiriquí Viejo water basin is located in the Chiriquí province of Panama which shares boarders with Costa Rica on the western borders of the country. It is characterized by an average altitude of 1100 mm and annual precipitation of 2476 mm which makes it suitable for hydropower production. The basin consists mainly of run-of-river schemes, with a daily regulation reservoir. The study consists of 7 power plants with a generation capacity greater than 20 MW. Five of the powerplants are in operation; Monte Lirio (52 MW) with no upstream storage, El Alto (72 MW), Bajo de Mina (57 MW), Baitun (86 MW) and Bajo Frio (58 MW) and two power plants, Pando (33 MW) and Burica ( 65 MW), planned to be introduced to the system between 2019 and 2023. The main objective of the study is to find strategies for the use of water in the cascade and optimize the hydropower production.A spreadsheet model and nMAG have been used in the study to simulate and optimize production. Operating the reservoirs at near full capacity increases production by 3.7% (37 GWh) annually with a reduction in operational time of 28% for El Alto, Bajo de Mina, Burica and Bajo Frio powerplants.nMAG has been used to conduct simulations for the future, current system and climate change impact on production. The introduction of Pando and Burica to the system increases the production of the Chiriquí Viejo basin by 528 GWh annually. The Upstream regulation of Pando will result in increased production at Monte Lirio hydropower powerplant of 0.1% (0.4 GWh) and 0.2 GWh for both Bajo de Mina and Baitun hydropower plants with the production increase mostly in the rainy season.Simulations based on climate change with the future setup show no significant impact on production. Inflow based on climate change studies from literature with a 12% reduction is still able to meet firm demand based on the strategy in nMAG.