Can a Calibration-Free Dynamic Rainfall‒Runoff Model Predict FDCs in Data-Scarce Regions? Comparing the IDW Model with the Dynamic Budyko Model in South India

Abstract

Construction of flow duration curves (FDCs) is a challenge for hydrologists as most streams and rivers worldwide are ungauged. Regionalization methods are commonly followed to solve the problem of discharge data scarcity by transforming hydrological information from gauged basins to ungauged basins. As a consequence, regionalization-based FDC predictions are not very reliable where discharge data are scarce quantitatively and/or qualitatively. In such a scenario, it is perhaps more meaningful to use a calibration-free rainfall‒runoff model that can exploit easily available meteorological information to predict FDCs in ungauged basins. This hypothesis is tested in this study by comparing a well-known regionalization-based model, the inverse distance weighting (IDW) model, with the recently proposed calibration-free dynamic Budyko model (DB) in a region where discharge observations are not only insufficient quantitatively but also show apparent signs of observational errors. The DB model markedly outperformed the IDW model in the study region. Furthermore, the IDW model’s performance sharply declined when we randomly removed discharge gauging stations to test the model in a variety of data availability scenarios. The analysis here also throws some light on how errors in observational datasets and drainage area influence model performance and thus provides a better picture of the relative strengths of the two models. Overall, the results of this study support the notion that a calibration-free rainfall‒runoff model can be chosen to predict FDCs in discharge data-scarce regions. On a philosophical note, our study highlights the importance of process understanding for the development of meaningful hydrological models.

Estimating Flood Magnitudes of Ungauged Urban Msimbazi River Catchment in Dar es Salaam, Tanzania

“…However, these catchments may have partial or fully available climate records at various locations within and around them. In such cases where data is scarce or unavailable, the hydrologists have developed models and techniques which do not require the availability of long time series of meteorological and hydrological observations (Loukas and Vasiliades, 2014;Blöschl et al, 2013;Botero and Francés, 2010;Nag and Biswal, 2019;Post, 2004). Depending on whether flow hydrographs, statistics or quantiles are the required outputs, several methods can be used including rainfall-runoff modelling using global parameters transfer, quantile estimation from empirical methods and time series summaries from flow duration curves (FDC) regional equation (Swain and Patra, 2017;Valimba, 2016;Loukas and Vasiliades, 2014).…”

Strategies to enhance the reliability of flow quantile prediction in the gauged and ungauged basins

“…They reported that the catchment runoff response similarity (CRRS) approach outperformed the other commonly used regionalization approaches for reproducing the desired hydrograph in the ungauged watersheds. Moreover, it has been reported that the performance of regionalization methods often influenced by the streamflow gauging station density (Müller, Thompson, & Sciences, ; Nag & Biswal, ; Oudin, Andréassian, Perrin, Michel, & Le Moine, ; Tegegne & Kim, ). However, Tegegne and Kim () reported the capability of the CRRS approach in different basins in terms of climate condition and stream gauging station network density.…”

“…Moreover, it has been reported that the performance of regionalization methods often influenced by the streamflow gauging station density (Müller, Thompson, & Sciences, 2016;Nag & Biswal, 2019;Oudin, Andréassian, Perrin, Michel, & Le Moine, 2008;Tegegne & Kim, 2018).…”