Simulation software packages are very useful tools for evaluating hydraulic conditions in gas systems, and therefore for supporting the design process, network maintenance and decisions about rerouting or modernisation of a network. In the range of this paper, a model of a real branched gas network covering 3 towns was created in the GAZNET software. At first, actual hydraulic conditions of gas flow in the pipes were simulated to evaluate distributions of flow velocity and pressure in the pipes. The obtained results indicated meaningful pressure drops and increase in flow velocity in some sections of the model, which not only constitutes a threat to provide required parameters of gas to consumers, but also forecloses connecting new consumers to the network. Thus, two variants of improvements were proposed: (1) expanding the network by building two additional sections or (2) increasing the number of gas sources by building additional pressure reduction and measuring unit. Conducted simulations indicated that changes of the network proposed in both variants clearly improve hydraulic conditions in the network model. However, the first variant was chosen as a better alternative, because distribution of hydraulic parameters in the model was more homogeneous than in the second variant, as well as because of economic considerations.