Gerald Souza Da Silva,Alain Marie Bernard Passerat de Silans,Cristiano das Neves Almeida,Ana Cristina Souza da Silva, UFPB, Water Resources and Environmental Engineering, gerald-silva@gmx.de
ABSTRACT
The timescale of a rainfall-runoff-model is an important issue for the results that are achieved by the model. Rainfalls can be very intense and occur in a few hours or can last longer with the same overall quantity. Intense rainfalls are regularly flooding critical areas. This paper studies the relation between timescale and runoff simulated by lumped rainfall-runoff-models. The study is held in the semi-arid region in north-east Brazil. The water levels of monitored dams are used to forecast the runoff with observed rainfall data. Especially in the semi-arid region rainfalls that fill up these dams will occur concentrated in some days or weeks. Simulations on a monthly timescale are often used because of the absence of long-term continuous daily runoff data and safer results. However, how exact are these simulation to provide data for the several uses like water supply and the sizing of dams and the risks related.
Key Words: Rainfall-runoff model, Time scale