Effect of Model Structure and Calibration Algorithm on Discharge Simulation

Abstract

In this study, Acısu Basin, which is upper side of one of the most important basins (Gediz) in Türkiye, was modelled using three types of hydrological models and three different calibration algorithms. Lumped (GR4J), semi-distributed (SWAT+), and fully distributed (mHM) hydrological models were built and integrated with Parameter Estimation Tool (PEST) which is a model independent calibration tool including various algorithms. Levenberg Marquardt (L-M), Shuffled Complex Evolution (SCE), and Covariance Matrix Adoption Evolution Strategy (CMA-ES) were selected as calibration algorithms. Calibration period was 1991-2000, and validation results were obtained for 2002-2005. The effect of model structure and calibration algorithm selection on discharge simulation was evaluated via comparison of 9 different model-algorithm combinations. Results have shown that mHM and CMA-ES combination showed the best discharge simulation performance according to NSE values (calibration: 0.67, validation: 0.60). Although statistically the model results were classified as acceptable, the pattern comparison of discharge value shows that all of the models miss the peak values in significant amounts. This problem may be related to the interventions made in 2000-2001 years interval and possible to overcome by changing the calibration and validation periods, increasing the number of iterations or using the naturalized gauge data.

Effect of Dynamic PET Scaling with LAI and Aspect on the Spatial Performance of a Distributed Hydrologic Model

“…Decisions concerning hydrological fluxes are based on model results, which hydrological modelers use to affect impulses. Numerous research has examined and estimated a range of input data that reflect those in conceptual and physically distributed models to better understand the various ways that models work [1,3,4,11,12,17,18,41].…”

“…The Muskingum method is used between cells and flow routing are obtained with this translation until the outlet. Instead of outlet flow, all cell flow can be seen in pattern [4].…”

“…More parameters can be used, and more accurate results can be obtained with increasing computer processing power. The accuracy of one basin model is increased by the availability of large data sets and computation methods [4].…”