Comparison of Simplified Hydraulic Routing Models for the Short-Term Optimization of Reservoir Systems (PAP014806)

Código

PAP014806

Autores

Julio Issao Kuwajima, Rodolfo Alvarado Montero, Dirk Schwanenberg, Fernando Mainardi Fan, ALBERTO ASSIS DOS REIS, Rosana de Fátima Colaço Gibertoni, Frederico Fabio Mauad

Tema

Flood forecasting and early warning systems

Resumo

An effective water resources management is important to meet multiple objectives such as water supply, navigation, hydroelectricity generation, environmental obligations and flood protection. By implementing a predictive control approach over a short-term forecast horizon, it is possible to foresee stress conditions or peak flow events and support decision-makers to take actions before these events happen for minimizing their impacts. In the case of flood events, this technique enables the operators to pre-release water from a reservoir for allocating additional storage before the flood event occurs for mitigating flood damage along downstream river reaches. A robust and fast routing model is required in order to obtain quick and reliable estimates of downstream flow conditions related to release changes of the reservoir. In this paper, four different models are assessed concerning their implementation in a predictive control of the Três Marias Reservoir located at the Upper River São Francisco in Brazil: i) a fully dynamic model using the software package SOBEK; ii) a semi-distributed rainfall-runoff model with Muskingum-Cunge routing for the flow reaches of interest, the MGB-IPH (Modelo Hidrológico de Grandes Bacias - Instituto de Pesquisas Hidráulicas); iii) a simplified reservoir routing and iv) a diffusive wave model. The last two models are implemented in the RTC-Tool toolbox. In general, we find comparable results between the simplified models in RTC-Tools and the more sophisticated SOBEK model and a lower performance of the MGB model. However, both hydraulic modeling approaches, i.e. the SOBEK model as well as the diffusive wave model in RTC-Tools, suffer from too much numerical diffusion in case of courser grids. In the reservoir routing approach, the introduction of pure advection by time lags offers an efficient cure for excessive numerical diffusion even on courser grids. From the predictive control point of view, this approach shows the best compromise in terms of robustness, computational efficiency and accuracy.