Model development for low flow estimations in river basins across the Mediterranean

Low-flows is a common phenomenon occurring in rivers during dry seasons within each hydrological year. Increased water demand and low availability during these seasons account for numerous water-resources management problems. Therefore, reliable flow estimation during dry seasons is an emerging topic in contemporary hydrology. Long term prognosis of river water potential helps stakeholders take better decisions for distributing resources (e.g. water for agriculture) and achieving good ecological status of the studied water body. Although low flows is a profoundly essential part of the hydrological cycle and can significantly affect management limited studies are found in literature. In contrast, most studies delve into resolving management problems by examining the water circle as a whole, including wet and dry seasons. This practice leads to the development of complex models and methodologies that are most often successful, but require expertise and specialized software. The objective of this thesis is to develop a simple yet efficient model for estimating low flows during dry seasons, suitable for use without specialized software or personnel. In order to design the model, daily runoff data from various Mediterranean basins are utilized (two from Greece, two from Cyprus, one from Italy). Runoff data are smoothed by simple signal processing techniques which filter the effect of flood events and retain the flow recession curve. Finally, models are presented in chart form for each one of the basin tested.