Articles | Volume 20, issue 7
Research article
15 Jul 2016
Research article |  | 15 Jul 2016

Parameter regionalization of a monthly water balance model for the conterminous United States

Andrew R. Bock, Lauren E. Hay, Gregory J. McCabe, Steven L. Markstrom, and R. Dwight Atkinson

Abstract. A parameter regionalization scheme to transfer parameter values from gaged to ungaged areas for a monthly water balance model (MWBM) was developed and tested for the conterminous United States (CONUS). The Fourier Amplitude Sensitivity Test, a global-sensitivity algorithm, was implemented on a MWBM to generate parameter sensitivities on a set of 109 951 hydrologic response units (HRUs) across the CONUS. The HRUs were grouped into 110 calibration regions based on similar parameter sensitivities. Subsequently, measured runoff from 1575 streamgages within the calibration regions were used to calibrate the MWBM parameters to produce parameter sets for each calibration region. Measured and simulated runoff at the 1575 streamgages showed good correspondence for the majority of the CONUS, with a median computed Nash–Sutcliffe efficiency coefficient of 0.76 over all streamgages. These methods maximize the use of available runoff information, resulting in a calibrated CONUS-wide application of the MWBM suitable for providing estimates of water availability at the HRU resolution for both gaged and ungaged areas of the CONUS.

Short summary
A parameter sensitivity analysis was applied to a monthly water balance model across the United States and used to identify regions of similar model response. Streamgages within each region were calibrated as a group to produce model parameters that can simulate streamflow in areas where measured streamflow data are limited or unavailable. Results showed good correspondence with measured values, except in areas where dominant hydrologic processes occurred at submonthly timescales.