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WATER RESOURCES RESEARCH, VOL. 43, W01413, doi:10.1029/2005WR004723, 2007

Dynamically dimensioned search algorithm for computationally efficient watershed model calibration

Bryan A. Tolson

Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada


Christine A. Shoemaker

School of Civil and Environmental Engineering, Cornell University, Ithaca, New York, USA


Abstract

A new global optimization algorithm, dynamically dimensioned search (DDS), is introduced for automatic calibration of watershed simulation models. DDS is designed for calibration problems with many parameters, requires no algorithm parameter tuning, and automatically scales the search to find good solutions within the maximum number of user-specified function (or model) evaluations. As a result, DDS is ideally suited for computationally expensive optimization problems such as distributed watershed model calibration. DDS performance is compared to the shuffled complex evolution (SCE) algorithm for multiple optimization test functions as well as real and synthetic SWAT2000 model automatic calibration formulations. Algorithms are compared for optimization problems ranging from 6 to 30 dimensions, and each problem is solved in 1000 to 10,000 total function evaluations per optimization trial. Results are presented so that future modelers can assess algorithm performance at a computational scale relevant to their modeling case study. In all four of the computationally expensive real SWAT2000 calibration formulations considered here (14, 14, 26, and 30 calibration parameters), results show DDS to be more efficient and effective than SCE. In two cases, DDS requires only 15–20% of the number of model evaluations used by SCE in order to find equally good values of the objective function. Overall, the results also show that DDS rapidly converges to good calibration solutions and easily avoids poor local optima. The simplicity of the DDS algorithm allows for easy recoding and subsequent adoption into any watershed modeling application framework.

Received 10 November 2005; accepted 31 August 2006; published 17 January 2007.

Keywords: automatic calibration; distributed watershed modeling; Global optimization.

Index Terms: 1879 Hydrology: Watershed; 1846 Hydrology: Model calibration (3333); 1847 Hydrology: Modeling.

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 1053068 bytes)

Citation: Tolson, B. A., and C. A. Shoemaker (2007), Dynamically dimensioned search algorithm for computationally efficient watershed model calibration, Water Resour. Res., 43, W01413, doi:10.1029/2005WR004723.