Combining radar quantitative precipitation estimates (QPEs) with distributed hydrological model for controlling transit of flash-flood upstream of crowded human habitats in Romania

This study aims to develop and adapt new methodologies for the foundation of a new hydrological system, essential component of a much-needed decision support spatial system for the Firiza basin and reservoir (North-West of Romania) and other areas situated upstream of a densely populated area. In order to utilize semi-distributed models in basins outside of the USA, in particular the application of an adaptation of the methodology for application of gridded precipitation within HEC-HMS in US regions covered by the hydrologic rainfall analysis projection and the standard hydrologic grid systems has been developed for Romania. This methodology allows for precipitation processing and estimation of loss parameters and runoff transformation parameters to areas outside of the USA and areas that were not covered under the initial formulation of the method. This adaptation enables an alternative forecasting method and a controlled model for the transit of flash floods through reservoirs, which was correlated with the result of precipitation forecast. Multiple sets of parameters have been compiled to represent a wet/typical condition: a snowy and a dry one. All river basin conditions were adjusted according to historical events, and two zone configurations were developed, including the gauge configuration assigned to the transformation and basic flow parameters, and the soil configuration assigned to the loss parameters. Igniș radar provides radar imagery into the future, taking into account advection, growth and decay, allowing for an accurate 0–1 h quantitative precipitation forecast. This capability provides extremely accurate short-term forecasting—80% accuracy over 15 min and 70% accuracy over 30 min—that is vital for near-term flash flood forecasting. The efficiency of the model ranged between the good and very good. The results will be used to manage extreme situations such as flash floods, which can generate major hydrological risk situations for thousands of residents in the Baia Mare urban area, located downstream of this reservoir.