DEVELOPMENT OF A SEMI-DISTRIBUTED HYDROLOGICAL MODEL TOOLBOX TO PREDICT RUNOFF RESPONSE IN THE UNGAUGED CATCHMENT OF MORNOS, GREECE

Prediction of runoff response in ungauged catchments has been one of the key issues in water science. Despite the considerable effort the hydrologic community has devoted over the past decade, there is still need to develop robust frameworks capable of representing the dynamic behaviours of catchment processes (e.g. streamflow). Runoff prediction has been particularly challenging in the poorly- or usually un- gauged Greek catchments, whereas predictions are subject to significant uncertainty due to erroneous and/or limited available data. The Athens Water Supply and Sewerage Company (EYDAP SA) has funded a project to measure, and simulate the hydrological fluxes (e.g. rainfall, snowfall, streamflow, evaporation) of the 560 km(2) Mornos catchment, Greece, that supplies the metropolitan area of Athens with fresh water. In this study, we present the Mornos Water Balance Model Toolbox (MWBMT) recently developed to simulate the hydrological processes in the catchment. Moreover, we improve the model performance by assimilating information provided by EYDAP SA (i.e. monthly runoff contribution and water level at the reservoir). The rainfall-runoff model structures are based on the Soil Conservation Service Curve Number (SCS-CN) method, whereas topographical, geological and land use information is used to complement parameter identification. In addition, a simple water balance equation is used to estimate the change in the reservoir's storage. The analysis is based on daily data from the available 15-month period to drive the original SCS-CN model aiming to support the reservoir's water management. Finally, we present the sources of error/uncertainty causing poor model performance over different time periods and point towards ways for improvement.