A new approach to modelling the average interannual streamflow in the watersheds of Northern Algeria

The estimation and potential exploitation of water resources in arid and semi-arid regions, especially in the watersheds of Northern Algeria, where climatic variability affects the transformation of precipitation into river flow, needs to be based on effective management of these resources depends on understanding hydrological relationships. This must be grounded in knowledge and probable mastery of the phenomena governing their formation under local physico-geographical conditions, particularly in ungauged watershed areas. The objective of this approach is to develop a general and regional model for estimating interannual average flow (IAF) at the level of ungauged basins. This model is based on the analysing and identifying the influence of local factors such as the surface area of the watershed, relief, geology, soils, and plant cover. Its development relies on statistical and grapho-analytical methods. The results demonstrate that the watershed area and climatic flow are key parameters, which indicate the dependency of the climatic coefficient kobs on these two factors and give good correlations, which vary from 0.615 to 0.92. Hence, the model was established based on these two parameters and found to perform well in estimating IAF, according to the performance criteria.