This thesis focuses on hydraulic tunnels, with special emphasis on their application in managing water flows and protecting construction sites from flooding. The introductory section covers the general characteristics of tunnels, such as their purpose, cross-section profile, longitudinal slope, lining, and more. The central part of the thesis is dedicated to the classification of tunnels based on flow conditions. The main categories, such as free-surface flow, flow with variable regimes, and pressurized flow, are explained, along with how these conditions influence tunnel design. In the final part of the thesis, a concrete example of the calculation and dimensioning of a bypass tunnel for the protection of a construction site from water is provided. The calculation includes determining the required tunnel diameter and the height of the upstream cofferdam to meet the existing flow conditions. The design is based on technical standards and norms, aiming to ensure the safety and stability of the structure. This thesis highlights the importance of proper tunnel design to ensure their functionality and safety in hydraulic engineering projects.