Assessment of dimension-reduction and grouping methods for catchment response time estimation in Hungary

Study region: 61 catchments located in Hungary, with drainage areas from 8.74 to 810 km2. Study focus: Many engineering tasks require the estimation of the catchment response time (Tr). The most frequently used Tr parameters are the time of concentration and the lag time. At ungauged catchments, the...

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Autores principales:	Eszter D. Nagy, Jozsef Szilagyi, Peter Torma
Formato:	article
Lenguaje:	EN
Publicado:	Elsevier 2021
Materias:	Catchment response time Dimension reduction Clustering Catchment grouping Empirical equation Physical geography GB3-5030 Geology QE1-996.5
Acceso en línea:	https://doaj.org/article/69860a88227b4edd8ec858d2354dac35
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spelling	oai:doaj.org-article:69860a88227b4edd8ec858d2354dac352021-11-26T04:29:48ZAssessment of dimension-reduction and grouping methods for catchment response time estimation in Hungary2214-581810.1016/j.ejrh.2021.100971https://doaj.org/article/69860a88227b4edd8ec858d2354dac352021-12-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S2214581821002007https://doaj.org/toc/2214-5818Study region: 61 catchments located in Hungary, with drainage areas from 8.74 to 810 km2. Study focus: Many engineering tasks require the estimation of the catchment response time (Tr). The most frequently used Tr parameters are the time of concentration and the lag time. At ungauged catchments, they are usually estimated by empirical equations that relate Tr to catchment characteristics. This paper provides a comparative study of three dimension-reduction techniques and seven clustering methods for fitting empirical equations to the observed values of Tr. 60 catchment descriptors were calculated for each catchment, then three subsets with 1–3 descriptors were extracted from the entire parameter set during the dimension-reduction analysis. Two and four catchment groups were created during a cluster analysis, by re-calibrating the three equations that resulted from the dimension-reduction analysis. New hydrological insights for the region under study: It is demonstrated that the principal component analysis can be easily outperformed by the linear correlation and the all-possible-regressions methods, the latter yielding a root-mean-squared error (RMSE) of 6.77 h when applied with three catchment descriptors. The most interesting finding of the dimension reduction is that Tr is strongly connected to field capacity in the region of study. The performance of the clustering methods varies considerably (RMSE = 5.05–12.03 h). The best overall performance comes from the residual approach (RMSE = 8.14 h on average). It is shown that several of the methods outperform the grouping based on geographical regions, however, the estimation error is reduced only in a few cases when compared to the regional estimation (i.e., one cluster) method. Clusters created based on catchment width yields the best results, resulting in RMSE values of 5.80 and 5.77 h (with two and four clusters, respectively). The comparison of the new and the existing empirical equations clearly demonstrated that the estimation of Tr needs improvement in Hungary, while the application of more than two clusters is unwarranted for the study region.Eszter D. NagyJozsef SzilagyiPeter TormaElsevierarticleCatchment response timeDimension reductionClusteringCatchment groupingEmpirical equationPhysical geographyGB3-5030GeologyQE1-996.5ENJournal of Hydrology: Regional Studies, Vol 38, Iss , Pp 100971- (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Catchment response time Dimension reduction Clustering Catchment grouping Empirical equation Physical geography GB3-5030 Geology QE1-996.5
spellingShingle	Catchment response time Dimension reduction Clustering Catchment grouping Empirical equation Physical geography GB3-5030 Geology QE1-996.5 Eszter D. Nagy Jozsef Szilagyi Peter Torma Assessment of dimension-reduction and grouping methods for catchment response time estimation in Hungary
description	Study region: 61 catchments located in Hungary, with drainage areas from 8.74 to 810 km2. Study focus: Many engineering tasks require the estimation of the catchment response time (Tr). The most frequently used Tr parameters are the time of concentration and the lag time. At ungauged catchments, they are usually estimated by empirical equations that relate Tr to catchment characteristics. This paper provides a comparative study of three dimension-reduction techniques and seven clustering methods for fitting empirical equations to the observed values of Tr. 60 catchment descriptors were calculated for each catchment, then three subsets with 1–3 descriptors were extracted from the entire parameter set during the dimension-reduction analysis. Two and four catchment groups were created during a cluster analysis, by re-calibrating the three equations that resulted from the dimension-reduction analysis. New hydrological insights for the region under study: It is demonstrated that the principal component analysis can be easily outperformed by the linear correlation and the all-possible-regressions methods, the latter yielding a root-mean-squared error (RMSE) of 6.77 h when applied with three catchment descriptors. The most interesting finding of the dimension reduction is that Tr is strongly connected to field capacity in the region of study. The performance of the clustering methods varies considerably (RMSE = 5.05–12.03 h). The best overall performance comes from the residual approach (RMSE = 8.14 h on average). It is shown that several of the methods outperform the grouping based on geographical regions, however, the estimation error is reduced only in a few cases when compared to the regional estimation (i.e., one cluster) method. Clusters created based on catchment width yields the best results, resulting in RMSE values of 5.80 and 5.77 h (with two and four clusters, respectively). The comparison of the new and the existing empirical equations clearly demonstrated that the estimation of Tr needs improvement in Hungary, while the application of more than two clusters is unwarranted for the study region.
format	article
author	Eszter D. Nagy Jozsef Szilagyi Peter Torma
author_facet	Eszter D. Nagy Jozsef Szilagyi Peter Torma
author_sort	Eszter D. Nagy
title	Assessment of dimension-reduction and grouping methods for catchment response time estimation in Hungary
title_short	Assessment of dimension-reduction and grouping methods for catchment response time estimation in Hungary
title_full	Assessment of dimension-reduction and grouping methods for catchment response time estimation in Hungary
title_fullStr	Assessment of dimension-reduction and grouping methods for catchment response time estimation in Hungary
title_full_unstemmed	Assessment of dimension-reduction and grouping methods for catchment response time estimation in Hungary
title_sort	assessment of dimension-reduction and grouping methods for catchment response time estimation in hungary
publisher	Elsevier
publishDate	2021
url	https://doaj.org/article/69860a88227b4edd8ec858d2354dac35
work_keys_str_mv	AT eszterdnagy assessmentofdimensionreductionandgroupingmethodsforcatchmentresponsetimeestimationinhungary AT jozsefszilagyi assessmentofdimensionreductionandgroupingmethodsforcatchmentresponsetimeestimationinhungary AT petertorma assessmentofdimensionreductionandgroupingmethodsforcatchmentresponsetimeestimationinhungary
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Assessment of dimension-reduction and grouping methods for catchment response time estimation in Hungary

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