Predicting daily flows in ungauged catchments: model regionalization from catchment descriptors at the Coweeta Hydrologic Laboratory, North Carolina

Abstract

Abstract:Regionalization approaches to daily streamflow prediction are investigated for 13 catchments in the Coweeta Hydrologic Laboratory using a conceptual rainfall-runoff model of low complexity (six parameters). Model parameters are considered to represent the dynamic response characteristics (DRCs) of a catchment. It is demonstrated that all catchments within the region cannot be assumed to have a similar hydrological behaviour, and thence a regionalization approach considering differences in physical catchment descriptors (PCDs) is required. Such a regionalization approach can be regarded as a top-down method, in the sense that factors controlling parameter variability are identified first within the entire region under study, and then such information is exploited to predict runoff in a smaller sub-region. Regionalization results reveal that consideration of interrelations between dependent variables, which here are the parameters of the rainfall-runoff model, can improve performance of regression as a regionalization method. Breaking the parameter correlation structure inherent in the model, and exploiting merely relationships between model parameters and PCDs (no matter how weakly related they are), can result in a significant decrease in regionalization performance. Also, high significance of regression between values of PCDs and DRCs does not guarantee a set of parameters with a good predictive power. When there is a reason to believe that, in the sense of hydrological behaviour, a gauged catchment resembles the ungauged catchment, then it may be worthwhile to adopt the entire set of calibrated parameters from the gauged catchment instead of deriving quantitative relationships between catchment descriptors and model parameters.

Evaluation of Regionalization Methods for Hourly Continuous Streamflow Simulation Using Distributed Models in Boreal Catchments

“…Kokkonen et al, 2003, Oudin et al, 2008Kim and Kaluarachchi, 2008), using averages of streamflow that are simulated from parameter sets transferred from the donor catchments or "output averaging" (e.g. Oudin et al, 2008) and ensemble simulations.…”

“…Kokkonen et al, 2003;McIntyre et al, 2005;Parajka et al, 2005;Oudin et al, 2008;Reichl et al, 2009;Zhang and Chiew, 2009;Samuel et al, 2011;Arsenault and Brissette, 2014), which is based on the assumption that similarity in some physical attributes that govern the runoff response could explain the hydrological similarity. This method is also based on either a single-donor catchment or multi-donor catchments.…”

“…multi-donor median of parameter set) and then transferring homogeneous parameter sets for the whole region for prediction. The only difference between this method and the "parameter averaging" pooling option by Kokkonen et al (2003), Oudin et al (2008) and Kim and Kaluarachchi (2008) is that the median rather than the mean values of parameters were used. However, a limitation of transferring either median or mean parameters is that the method transfers the regional median or mean of each parameter rather than a set of optimal parameters and hence does not keep the correlation structure of the calibrated model parameters.…”

Simulation of the Effect of Land Cover Change on Water Balance and Sediment Yield of Wadi El Raml in the North Western Coast, Egypt

“…El Raml. Many studies have proved the effectiveness of transferring the calibrated parameters from gauged to ungauged watershed in simulating the flow dynamics (Kokkonen et al, 2003, Bardossy et al, 2007and Gao et al, 2015. RESULTS AND DISCUSSION Wadi El-Raml has faced significant land use changes in the last 15 -20 years where several farmers started to use ground water to establish and irrigate small fields of vegetable crops as well as converting the rangelands into areas of rainfed crop cultivation including barley and wheat.…”

Discussion on the Flood Volume Investigation for the Ungauged Catchments

“…Slope-area method is the main method to flood investigation, but it is only get the flood discharge. Five points probable was used to calculate the flood volume by investigation, it still either need measured time parameter, or need has single peak flood progress [9][10].…”