This thesis examines the performance of the Along-Stream approach in the prediction of flood statistics in ungauged basins and compares it with a regional approach officially in use in the Po river district in Italy. This method, introduced by Ganora (2013), is here used for a larger dataset of 175 basins with three additional distance definitions. Distance definitions based on basin area, Euclidean distance between the basins, basin mean elevation and the combination of basin area and mean elevation are investigated. The study attempts to assess how different distance-threshold levels change the uncertainty of the estimates propagated and derived compared to the regional model.