Using hydrodynamic model for flow calculation from level measurements

ABSTRACT

The use of hydrodynamic models to determine stream discharges has been grown in recent years due to the problems regarding the use of rating curve method for discharge estimating. This study aims to develop a method for determining discharges in open channels using multiobjective evolutionary algorithms (NSGA-II) and free surface level measurements associated with a hydrodynamic model. Data obtained from experiments on a laboratory experimental channel have been used for model calibration and validation. NSGA-II optimization algorithm presented excellent results and Nash-Sutcliffe coefficients greater than 0.99 have been obtained for both calibration and validation of the hydrodynamic model. Discharges calculated by the hydrodynamic model showed variations of up to 150% for the same level when compared to the discharges estimated by the rating curve, which showed that the use of rating curve for discharge measurements during transient flows results in high errors.

Keywords:
Multiobjective optimization; Saint-Venant equations; Transient flow; NSGA-II; Rating curve