Improved methods for daily streamflow estimates at ungauged sites

Abstract

[1] In this paper, improved flow duration curve (FDC) and area ratio (AR) based methods are developed to obtain better daily streamflow estimation at ungauged sites. A regression based logarithmic interpolation method which makes no assumption on the distribution or shape of a FDC is introduced in this paper to estimate regional FDCs. The estimated FDC is combined with a spatial interpolation algorithm to obtain daily streamflow estimates. Multiple source sites based AR methods, especially the geographical distance weighted AR (GWAR) method, are introduced in an effort to maximize the use of regional information and improve the standard AR method (SAR). Performances of the proposed approaches are evaluated using a jackknife procedure. The application to 109 stations in the province of Quebec, Canada indicates that the FDC based methods outperform AR based methods in all the summary statistics including Nash, root mean squared error (RMSE), and Bias. The number of sites that show better performances using the FDC based approaches is also significantly larger than the number of sites showing better performances using AR based methods. Using geographical distance weighted multiple sources sites based approaches can improve the performance at the majority of the catchments comparing with using the single source site based approaches.Citation: Shu, C., and T. B. M. J. Ouarda (2012), Improved methods for daily streamflow estimates at ungauged sites, Water Resour.

Transferability of hydrological model parameter spaces in the estimation of runoff in ungauged catchments

“…Related hydrological studies also suggested that the number of donor catchments required to improve hydrological model performance at ungauged catchments varies from 5 to 10 (e.g. McIntyre et al 2005, Oudin et al 2008, Zhang and Chiew 2009, Patil and Stieglitz 2011, Shu and Ouarda 2012.…”

Predicting streamflows in snowmelt-driven watersheds using the flow duration curve method

“…It is apparent that the semi-distributed model provides the most trustworthy results due to its better performance. Shu and Ouarda (2012) recommended at least four streamflow observations as donor variables for good precision with the FDC methods. Thus, the regional FDC with two streamflows and I CP in this study could add more uncertainty than a case with more donor variables.…”

“…Thus, one or multiple donor variables close to the target station have been typically used in the regional FDC approaches. Shu and Ouarda (2012) suggested using multiple donor variables to minimize the uncertainty of using a single donor variable. This study used two sets of neighboring streamflow observations as well as I CP to generate streamflows in sub-watersheds.…”

“…A parametric approach was selected for constructing the regional FDC. The model proposed by Shu and Ouarda (2012) was used and given as…”

“…Many regional FDC methods have been proposed for generating streamflows in ungauged watersheds. Shu and Ouarda (2012) categorized the regional FDC methods as a statistical approach (e.g., Claps et al, 2005), a parametric approach (e.g., Yu et al, 2002;Mohamoud, 2008), and a graphical approach (e.g., Smakhtin et al, 1997).…”