Rapid social and economic development, along with human-induced climate change, have posed challenges for global water security. A model was developed for managing water resources in the Mid-lower Hanjiang River Basin in China, considering future climate scenarios, water demand, reservoir operations, and water allocation. Adaptive water resource allocation programs were designed to address changing climate, increasing water demand, and planned water diversion projects. The study found that rising water demand and inter-basin water transfers could negatively impact water supply reliability along the Hanjiang River. Climate variations are expected to affect water supply in the study area, with a wide range of impacts. Water supply risks in the Mid-lower Hanjiang River Basin are projected to increase in most scenarios.