TY - JOUR

T1 - Stage-discharge uncertainty derived with a non-stationary rating curve in the Choluteca River, Honduras

AU - Westerberg, Ida

AU - Guerrero, Jose-Luis

AU - Seibert, Jan

AU - Beven, Keith

AU - Halldin, Sven

PY - 2011

Y1 - 2011

N2 - Uncertainty in discharge data must be critically assessed before data can be used in, e.g. water resources estimation or hydrological modelling. In the alluvial Choluteca River in Honduras, the river-bed characteristics change over time as fill, scour and other processes occur in the channel, leading to a non-stationary stage-discharge relationship and difficulties in deriving consistent rating curves. Few studies have investigated the uncertainties related to non-stationarity in the stage-discharge relationship. We calculated discharge and the associated uncertainty with a weighted fuzzy regression of rating curves applied within a moving time window, based on estimated uncertainties in the observed rating data. An 18-year-long dataset with unusually frequent ratings (1268 in total) was the basis of this study. A large temporal variability in the stage-discharge relationship was found especially for low flows. The time-variable rating curve resulted in discharge estimate differences of − 60 to + 90% for low flows and ± 20% for medium to high flows when compared to a constant rating curve. The final estimated uncertainty in discharge was substantial and the uncertainty limits varied between − 43 to + 73% of the best discharge estimate.

AB - Uncertainty in discharge data must be critically assessed before data can be used in, e.g. water resources estimation or hydrological modelling. In the alluvial Choluteca River in Honduras, the river-bed characteristics change over time as fill, scour and other processes occur in the channel, leading to a non-stationary stage-discharge relationship and difficulties in deriving consistent rating curves. Few studies have investigated the uncertainties related to non-stationarity in the stage-discharge relationship. We calculated discharge and the associated uncertainty with a weighted fuzzy regression of rating curves applied within a moving time window, based on estimated uncertainties in the observed rating data. An 18-year-long dataset with unusually frequent ratings (1268 in total) was the basis of this study. A large temporal variability in the stage-discharge relationship was found especially for low flows. The time-variable rating curve resulted in discharge estimate differences of − 60 to + 90% for low flows and ± 20% for medium to high flows when compared to a constant rating curve. The final estimated uncertainty in discharge was substantial and the uncertainty limits varied between − 43 to + 73% of the best discharge estimate.

KW - discharge

KW - uncertainty

KW - alluvial river

KW - stage-discharge

KW - rating curve

KW - fuzzy regression

U2 - 10.1002/hyp.7848

DO - 10.1002/hyp.7848

M3 - Journal article

VL - 25

SP - 603

EP - 613

JO - Hydrological Processes

JF - Hydrological Processes

SN - 0885-6087

IS - 4

ER -