Trends in timing of low stream flows in Canada: impact of autocorrelation and long‐term persistence

Ehsanzadeh, Eghbal; Adamowski, Kaz

doi:10.1002/hyp.7533

Cited by 72 publications

(42 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results confirm the variability and hence complexity of changes in low flows found in other temperate to cold climate regions (e.g. Burn et al, 2010;Ehsanzadeh and Adamowski, 2010).…”

Section: European Patterns Of Streamflow Trendssupporting

confidence: 86%

Streamflow trends in Europe: evidence from a dataset of near-natural catchments

Stahl

Hisdal

Hannaford

et al. 2010

Hydrol. Earth Syst. Sci.

410

295

View full text Add to dashboard Cite

Abstract. Streamflow observations from near-natural catchments are of paramount importance for detection and attribution studies, evaluation of large-scale model simulations, and assessment of water management, adaptation and policy options. This study investigates streamflow trends in a newly-assembled, consolidated dataset of near-natural streamflow records from 441 small catchments in 15 countries across Europe. The period 1962The period -2004 provided the best spatial coverage, but analyses were also carried out for longer time periods (with fewer stations), starting in 1932, 1942 and 1952. Trends were calculated by the slopes of the Kendall-Theil robust line for standardized annual and monthly streamflow, as well as for summer low flow magnitude and timing. A regionally coherent picture of annual streamflow trends emerged, with negative trends in southern and eastern regions, and generally positive trends elsewhere. Trends in monthly streamflow for 1962-2004 elucidated potential causes for these changes, as well as for changes in hydrological regimes across Europe. Positive trends were found in the winter months in most catchments. A marked shift towards negative trends was observed in April, gradually spreading across Europe to reach a maximum extentCorrespondence to: K. Stahl (kerstin.stahl@hydrology.uni-freiburg.de) in August. Low flows have decreased in most regions where the lowest mean monthly flow occurs in summer, but vary for catchments which have flow minima in winter and secondary low flows in summer. The study largely confirms findings from national and regional scale trend analyses, but clearly adds to these by confirming that these tendencies are part of coherent patterns of change, which cover a much larger region. The broad, continental-scale patterns of change are mostly congruent with the hydrological responses expected from future climatic changes, as projected by climate models. The patterns observed could hence provide a valuable benchmark for a number of different studies and model simulations.

show abstract

“…These results confirm the variability and hence complexity of changes in low flows found in other temperate to cold climate regions (e.g. Burn et al, 2010;Ehsanzadeh and Adamowski, 2010).…”

Section: European Patterns Of Streamflow Trendssupporting

confidence: 86%

Streamflow trends in Europe: evidence from a dataset of near-natural catchments

Stahl

Hisdal

Hannaford

et al. 2010

Hydrol. Earth Syst. Sci.

410

295

View full text Add to dashboard Cite

show abstract

“…The BHMLLESS-MK test accounts only for lag-one autoregressive (AR(1)) processes that are known to be the representatives of so-called short-term persistence (STP). However, Ehsanzadeh and Adamowski (2010), Khaliq et al (2008Khaliq et al ( , 2009a or Khaliq and Sushama (2012) pointed out that the series relative to hydrological drought such as low flows or their timings may also be governed by a stochastic process revealing long-term persistence (LTP). Through Monte Carlo simulations, for example, Hamed (2008) showed the MK tests may still overestimate the number of significant trends in hydrological series when ignoring the assumption of LTP.…”

Section: O Ledvinka: Evolution Of Low Flows In Czechia Revisitedmentioning

confidence: 99%

Evolution of low flows in Czechia revisited

Ledvinka

2015

Proc. IAHS

View full text Add to dashboard Cite

Abstract. Although a nationwide study focusing on the evolution of low flows in Czechia was conducted in the past, a need for the revision of the results has arisen. By means of the trend analysis, which specifically considers the presence of significant serial correlation at the first lag, the former study highlighted areas where 7-day low flows increase or decrease. However, taking into account only the lag-one autoregressive process might still have led to the detection of so-called pseudo-trends because, besides short-term persistence, also long-term persistence may adversely influence the variance of the test statistic when the independence among data is required. Therefore, one should carefully investigate the presence of persistence in time series. Before the trend analysis itself, the authors' previous studies aimed at the discrimination between short memory processes and long memory processes employing jointly the Phillips-Perron test and the Kwiatkowski-Phillips-Schmidt-Shin test. This analysis was accompanied by the Hurst exponent estimation. Here, the subsequent identification of trends is carried out using three modifications of the Mann-Kendall test that allow different kinds of persistence. These include the Bayley-Hammersley-Matalas-Langbein-Lettenmaier equivalent sample size approach, the trend-free pre-whitening approach and a block bootstrap with automatic selection of the block length, which was applied for the first time in hydrology. The general results are similar to those presented in the former study on trends. Nevertheless, the divergent minimum discharges evolution in the western part of Czechia is now much clear. Moreover, no significant increasing trend in series incorporating Julian days was found.

show abstract

“…Zhang et al 2001, Burn and Hag Elnur 2002, Yue et al 2001, Cunderlik and Burn 2004, Hodgkins and Dudley 2006, Khaliq et al 2008, Ehsanzadeh and Adamowski 2009, Burn et al 2010. The trend analysis studies have differed in: the variables examined, the approach used to identify trends, and the scope of the analysis, some studies being national in scope, while others have examined specific regions of Canada.…”

Section: Canadian Reference Networkmentioning

confidence: 99%

Reference hydrologic networks I. The status and potential future directions of national reference hydrologic networks for detecting trends

Whitfield

Burn

Hannaford

et al. 2012

Hydrological Sciences Journal

View full text Add to dashboard Cite

Identifying climate-driven trends in river flows on a global basis is hampered by a lack of long, quality time series data for rivers with relatively undisturbed regimes. This is a global problem compounded by the lack of support for essential long-term monitoring. Experience demonstrates that, with clear strategic objectives, and the support of sponsoring organizations, reference hydrologic networks can constitute an exceptionally valuable data source to effectively identify, quantify and interpret hydrological change-the speed and magnitude of which is expected to a be a primary driver of water management and flood alleviation strategies through the future-and for additional applications. Reference hydrologic networks have been developed in many countries in the past few decades. These collections of streamflow gauging stations, that are maintained and operated with the intention of observing how the hydrology of watersheds responds to variations in climate, are described. The status of networks under development is summarized. We suggest a plan of actions to make more effective use of this collection of networks.Key words reference networks; hydrometric data; hydrological change Les réseaux hydrologiques de référence I. Le statut et les orientations futures possibles des réseaux hydrologiques nationaux de référence pour détecter les tendancesRésumé L'identification de tendances induites par le climat dans le débit des rivières est entravée par le manque de longues séries chronologiques de qualité provenant de rivières dont le régime est peu altéré. Ce problème global est aggravé par le manque de soutien aux initiatives de suivi à long terme. L'expérience démontre qu'avec des objectifs stratégiques clairs ainsi qu'avec le soutien d'organismes de parrainage, les réseaux de référence hydrologiques peuvent s'avérer une précieuse source de données pour l'identification, la quantification et l'interprétation des changements hydrologiques. La vitesse et l'ampleur de ces derniers seront probablement à l'avenir des éléments importants pour la gestion de l'eau et la lutte contre les inondations. C'est pourquoi, d'autres applications étant sans doute à prévoir, des réseaux hydrologiques de référence ont été établis dans plusieurs pays au cours des dernières décennies. On décrit ces ensembles de stations de suivi hydrométrique, maintenues et exploitées dans l'intention d'observer comment l'hydrologie des bassins versants répond aux variations climatiques, ainsi que l'état actuel de développement de ces réseaux. Nous suggérons un plan d'action visant une utilisation plus efficace de ces réseaux.Mots clefs réseaux de référence; données hydrométriques; changement hydrologique

show abstract

Trends in timing of low stream flows in Canada: impact of autocorrelation and long‐term persistence

Cited by 72 publications

References 39 publications

Streamflow trends in Europe: evidence from a dataset of near-natural catchments

Streamflow trends in Europe: evidence from a dataset of near-natural catchments

Evolution of low flows in Czechia revisited

Reference hydrologic networks I. The status and potential future directions of national reference hydrologic networks for detecting trends

Contact Info

Product

Resources

About