This article uses hydropower development on the Lancang (upper Mekong River) and Nu (upper Salween River) as a lens for exploring institutional change and decision-making processes among governmental units and hydropower companies under the Great Western Development campaign. Scholars of the campaign tend to focus on central government policies and individual provinces' responses, and on the campaign's role as a central-state-strengthening project aimed at curbing regionalist tendencies. Large-scale hydropower development in Yunnan, however, is a complex affair involving national and provincial power companies, regional grids and governmental units at many levels. Conceptualizing Yunnan as the “powershed” of Guangdong, I argue that the Western Development campaign paves the way for increasingly strong interprovincial linkages between Guangdong and Yunnan that are not necessarily central-state-strengthening, and that consideration of such linkages should be fundamental to any attempt to understand the impacts of China's western development.