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Hydrology Research Vol 44 No 3 pp 430–440 © IWA Publishing 2013
Ian G. Littlewood and Barry F. W. Croke.
IGL Environment, Didcot, Oxfordshire OX11 7XN, UK, E-mail: [email protected] AND
Department of Mathematics, Fenner School of Environment and Society and National Centre for Groundwater Research and Training, The Australian National University, Canberra, Australia
Abstract
The effects of data time-step on the accuracy of calibrated parameters in a discrete-time conceptual rainfall–streamflow model are reviewed and further investigated. A quick-flow decay time constant of 19.9 hr, calibrated for the 10.6 km2 Wye at Cefn Brwyn using daily data, massively overestimates a reference value of 3.76 hr calibrated using hourly data (an inaccuracy of 16.1 hr or 429%). About 42 and 58% of the inaccuracy are accounted for by loss of information in the effective rainfall and streamflow data, respectively. A slow-flow decay time constant is inaccurate by about +111%, of which about 94 and 17 percentage points (85 and 15% of the absolute inaccuracy) are due to loss of information in the effective rainfall and streamflow data, respectively. Discrete-time rainfall–streamflow model parameter inaccuracy caused by data time-step effects is discussed in terms of its implications for parameter regionalisation (including database aspects) and catchment-scale process studies.
