The book presents a historical and technical study of the hydraulic system known as the old outlet channel of Lake Trasimeno, an engineering work designed to regulate the water level of the lake and protect the surrounding settlements and agricultural land. After introducing the geographical and historical context of the Trasimeno basin, the volume examines the origins of the project during the Renaissance period and the successive interventions that modified and maintained the structure. The text discusses the construction methods, the functioning of the outlet and its significance within regional water management. Illustrated documentation and diagrams accompany the narrative and help explain the relationship between landscape, infrastructure and historical development of the area. In this way the publication serves both as a historical study and as a documentation project supporting the cultural recognition of the lake and its hydraulic heritage.