The Role of Hydrological Signatures in Calibration of Conceptual Hydrological Model

Eva Melišová,Linda R Staponites,Adam Vizina,Martin Hanel

doi:10.3390/w12123401

Eva Melišová, Linda R Staponites + Show 2 more

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https://doi.org/10.3390/w12123401

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Abstract

Determining an optimal calibration strategy for hydrological models is essential for a robust and accurate water balance assessment, in particular, for catchments with limited observed data. In the present study, the hydrological model Bilan was used to simulate hydrological balance for 20 catchments throughout the Czech Republic during the period 1981–2016. Calibration strategies utilizing observed runoff and estimated soil moisture time series were compared with those using only long-term statistics (signatures) of runoff and soil moisture as well as a combination of signatures and time series. Calibration strategies were evaluated considering the goodness-of-fit, the bias in flow duration curve and runoff signatures and uncertainty of the Bilan model. Results indicate that the expert calibration and calibration with observed runoff time series are, in general, preferred. On the other hand, we show that, in many cases, the extension of the calibration criteria to also include runoff or soil moisture signatures is beneficial, particularly for decreasing the uncertainty in parameters of the hydrological model. Moreover, in many cases, fitting the model with hydrological signatures only provides a comparable fit to that of the calibration strategies employing runoff time series.

Highlights

Hydrological models are commonly employed to calculate the hydrological balance of a catchment using various calibration strategies
We assessed the performance of a conceptual runoff model (Bilan) calibrated using hydrological signatures based on long term runoff and soil moisture characteristics
The performance of tested combinations of runoff and soil moisture time series and signatures is evaluated with respect to goodness-of-fit (GOF) between simulated and observed runoff, uncertainty of the estimated Bilan model parameters (BP) and runoff signatures (RS) representing low and high flows

Summary

Introduction

Hydrological models are commonly employed to calculate the hydrological balance of a catchment using various calibration strategies (i.e., diverse objective criteria including various variables, different optimization algorithms, etc.). The applied calibration strategy affects the performance of the hydrological model. The widely used manual (expert) calibration of parameters is strongly influenced by the experience of the hydrologist; it is time-consuming and strongly affects the quality of the calibrated model [1]. The automatic calibration, on the other hand, is fast and the performance of the model simulations are explicitly linked to the parameter values within the optimization criteria. The automatic calibration of hydrological models typically uses observed runoff time-series to optimize the parameters. This is, not possible in catchments with limited observations, especially if gauged stations are not available. Due to equifinality, models of similar (good) performance may result from models with very different parameter sets and not simulate the physical processes properly

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