Appraisal of regional and index flood quantile estimators

1995 ◽  
Vol 9 (1) ◽  
pp. 49-75 ◽  
Author(s):  
J. R. Stedinger ◽  
L. -H. Lu
Keyword(s):  
Index Flood ◽  
Quantile Estimators

scholarly journals Uncertainty of quantile estimators using the population index flood method

2003 ◽  
Vol 39 (8) ◽  
Author(s):  
O. G. B. Sveinsson ◽  
J. D. Salas ◽  
D. C. Boes
Keyword(s):  
Population Index ◽  
Index Flood ◽  
Quantile Estimators

scholarly journals Delineation of homogenous regions using hydrological variables predicted by projection pursuit regression

2016 ◽  
Vol 20 (12) ◽  
pp. 4717-4729 ◽  
Author(s):  
Martin Durocher ◽  
Fateh Chebana ◽  
Taha B. M. J. Ouarda
Keyword(s):  
Target Location ◽  
Projection Pursuit ◽  
Flood Frequency ◽  
Flood Frequency Analysis ◽  
Projection Pursuit Regression ◽  
Index Flood ◽  
Regional Flood Frequency Analysis ◽  
Quantile Estimates ◽  
Target Locations ◽  
Hydrological Variables

Abstract. This study investigates the utilization of hydrological information in regional flood frequency analysis (RFFA) to enforce desired properties for a group of gauged stations. Neighbourhoods are particular types of regions that are centred on target locations. A challenge for using neighbourhoods in RFFA is that hydrological information is not available at target locations and cannot be completely replaced by the available physiographical information. Instead of using the available physiographic characteristics to define the centre of a target location, this study proposes to introduce estimates of reference hydrological variables to ensure a better homogeneity. These reference variables represent nonlinear relations with the site characteristics obtained by projection pursuit regression, a nonparametric regression method. The resulting neighbourhoods are investigated in combination with commonly used regional models: the index-flood model and regression-based models. The complete approach is illustrated in a real-world case study with gauged sites from the southern part of the province of Québec, Canada, and is compared with the traditional approaches such as region of influence and canonical correlation analysis. The evaluation focuses on the neighbourhood properties as well as prediction performances, with special attention devoted to problematic stations. Results show clear improvements in neighbourhood definitions and quantile estimates.

scholarly journals Heterogeneity measures in hydrological frequency analysis: review and new developments

2017 ◽  
Vol 21 (3) ◽  
pp. 1651-1668 ◽  
Author(s):  
Ana I. Requena ◽  
Fateh Chebana ◽  
Taha B. M. J. Ouarda
Keyword(s):  
Basic Step ◽  
New Developments ◽  
Ungauged Sites ◽  
Index Flood ◽  
Step Procedure ◽  
Homogeneous Regions ◽  
The Impact ◽  
Region Size ◽  
Degree Of Heterogeneity ◽  
Illustrative Application

Abstract. Some regional procedures to estimate hydrological quantiles at ungauged sites, such as the index-flood method, require the delineation of homogeneous regions as a basic step for their application. The homogeneity of these delineated regions is usually tested providing a yes/no decision. However, complementary measures that are able to quantify the degree of heterogeneity of a region are needed to compare regions, evaluate the impact of particular sites, and rank the performance of different delineating methods. Well-known existing heterogeneity measures are not well-defined for ranking regions, as they entail drawbacks such as assuming a given probability distribution, providing negative values and being affected by the region size. Therefore, a framework for defining and assessing desirable properties of a heterogeneity measure in the regional hydrological context is needed. In the present study, such a framework is proposed through a four-step procedure based on Monte Carlo simulations. Several heterogeneity measures, some of which commonly known and others which are derived from recent approaches or adapted from other fields, are presented and developed to be assessed. The assumption-free Gini index applied on the at-site L-variation coefficient (L-CV) over a region led to the best results. The measure of the percentage of sites for which the regional L-CV is outside the confidence interval of the at-site L-CV is also found to be relevant, as it leads to more stable results regardless of the regional L-CV value. An illustrative application is also presented for didactical purposes, through which the subjectivity of commonly used criteria to assess the performance of different delineation methods is underlined.

scholarly journals Regional Flood Frequency Analysis using Dimensionless Index Flood Method

2020 ◽  
Vol 6 (12) ◽  
pp. 2425-2436
Author(s):  
Andy Obinna Ibeje ◽  
Ben N. Ekwueme
Keyword(s):  
Flood Frequency ◽  
Flood Frequency Analysis ◽  
Accurate Estimation ◽  
Frequency Curve ◽  
Model Framework ◽  
Index Flood ◽  
Extreme Flood ◽  
Regional Flood Frequency Analysis ◽  
Spatially Distributed ◽  
Regional Flood Frequency

Hydrologic designs require accurate estimation of quartiles of extreme floods. But in many developing regions, records of flood data are seldom available. A model framework using the dimensionless index flood for the transfer of Flood Frequency Curve (FFC) among stream gauging sites in a hydrologically homogeneous region is proposed.  Key elements of the model framework include: (1) confirmation of the homogeneity of the region; (2) estimation of index flood-basin area relation; (3) derivation of the regional flood frequency curve (RFFC) and deduction of FFC of an ungauged catchment as a product of index flood and dimensionless RFFC. As an application, 1983 to 2004 annual extreme flood from six selected gauging sites located in Anambra-Imo River basin of southeast Nigeria, were used to demonstrate that the developed index flood model: , overestimated flood quartiles in an ungauged site of the basin.  It is recommended that, for wider application, the model results can be improved by the availability and use of over 100 years length of flood data spatially distributed at critical locations of the watershed. Doi: 10.28991/cej-2020-03091627 Full Text: PDF

ROBUST TEST BASED ON NONLINEAR REGRESSION QUANTILE ESTIMATORS

2005 ◽  
Vol 20 (1) ◽  
pp. 145-159 ◽  
Author(s):  
SEUNG-HOE CHOI ◽  
KYUNG-JOONG KIM ◽  
MYUNG-SOOK LEE
Keyword(s):  
Nonlinear Regression ◽  
Robust Test ◽  
Regression Quantile ◽  
Quantile Estimators

scholarly journals Estimating the UK Index Flood: an Improved Spatial Flooding Analysis

2020 ◽  
Vol 25 (5) ◽  
pp. 731-748
Author(s):  
Marinah Muhammad ◽  
Zudi Lu
Keyword(s):  
Index Flood ◽  
The Uk
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