Panel regressions to estimate low-flow response to rainfall variability in ungaged basins

Water Resources Research
By: , and 



Multicollinearity and omitted-variable bias are major limitations to developing multiple linear regression models to estimate streamflow characteristics in ungaged areas and varying rainfall conditions. Panel regression is used to overcome limitations of traditional regression methods, and obtain reliable model coefficients, in particular to understand the elasticity of streamflow to rainfall. Using annual rainfall and selected basin characteristics at 86 gaged streams in the Hawaiian Islands, regional regression models for three stream classes were developed to estimate the annual low-flow duration discharges. Three panel-regression structures (random effects, fixed effects, and pooled) were compared to traditional regression methods, in which space is substituted for time. Results indicated that panel regression generally was able to reproduce the temporal behavior of streamflow and reduce the standard errors of model coefficients compared to traditional regression, even for models in which the unobserved heterogeneity between streams is significant and the variance inflation factor for rainfall is much greater than 10. This is because both spatial and temporal variability were better characterized in panel regression. In a case study, regional rainfall elasticities estimated from panel regressions were applied to ungaged basins on Maui, using available rainfall projections to estimate plausible changes in surface-water availability and usable stream habitat for native species. The presented panel-regression framework is shown to offer benefits over existing traditional hydrologic regression methods for developing robust regional relations to investigate streamflow response in a changing climate.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Panel regressions to estimate low-flow response to rainfall variability in ungaged basins
Series title Water Resources Research
DOI 10.1002/2016WR018718
Volume 52
Issue 12
Year Published 2016
Language English
Publisher AGU
Contributing office(s) Pacific Islands Water Science Center
Description 25 p.
First page 9470
Last page 9494
Country United States
State Hawaii
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