Dependency of summer lake inflows and precipitation on spring SOI

McKerchar, Alistair I; Pearson, C. P.; Fitzharris, B. B.

doi:10.1016/s0022-1694(97)00144-3

Cited by 45 publications

(32 citation statements)

References 7 publications

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“…The link between rainfall and streamflow and ENSO is statistically significant in most parts of Australia. McKerchar et al (1998), investigating the dependency of summer lake inflow in southern New Zealand and precipitation on spring Southern oscillation index (SOI), showed that the variance of inflow and precipitation appears to be dependent on the magnitude of the SOI. Kane (1999) studied the association between El Niño and droughts in South Asia and China.…”

Section: Introductionmentioning

confidence: 99%

Long‐term trend analysis for precipitation in Asian Pacific FRIEND river basins

Takeuchi

Ishidaira

et al. 2005

Hydrological Processes

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Abstract:In order to analyse the long-term trend of precipitation in the Asian Pacific FRIEND region, records from 30 river basins to represent the large range of climatic and hydrological characteristics in the study area are selected. The long-term trend in precipitation time series and its association with the southern oscillation index (SOI) series are investigated. Application of the nonparametric Mann-Kendall test for 30 precipitation time series has shown that only four of these 30 time series have a long-term trend at the 5% level of significance. Nevertheless, most of the records tend to decrease over the last several decades. The dataset is further divided geographically into northern, middle, and southern zones, with 20°N and 20°S latitude as the dividing lines. The middle zone has the greatest variation and the southern zone the least variation over the past century. Also, the southern zone has greater variation during the past 30 years. The association between precipitation and SOI is investigated by dividing the precipitation records of each station into El Niño, La Niña, and neutral periods. The Wilcoxon rank-sum test showed that differences in precipitation for the three classes were most marked in the southern zone of the study area. The frequencies of below-and above-average precipitation for El Niño, La Niña, and neutral periods are estimated for the 30 precipitation time series as well. The results show that the frequencies of precipitation under each set of conditions, with lower precipitation generally associated with El Niño periods in the southern zone.

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Section: Introductionmentioning

confidence: 99%

Long‐term trend analysis for precipitation in Asian Pacific FRIEND river basins

Takeuchi

Ishidaira

et al. 2005

Hydrological Processes

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“…Chiew & McMahon (2002) included New Zealand hydrological data in a global study of the influences of the ENSO phenomenon on streamflow. Previous studies have examined the influences of the ENSO phenomenon on streamflow in New Zealand (McKerchar & Pearson, 1998;Mosley, 2000) and have demonstrated that influences occur mainly in the northeast of the North Island and in the axial ranges of the South Island. The aim of this study is to investigate where shifts in regime of high and low flow consistent with IPO shifts have occurred in New Zealand.…”

Section: Introductionmentioning

confidence: 99%

Shifts in flood and low-flow regimes in New Zealand due to interdecadal climate variations

McKerchar

Henderson

2003

Hydrological Sciences Journal

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Thirty-one of the longest available streamflow records for New Zealand were analysed to see whether shifts in flood and low-flow regime occurred in 1977/1978 corresponding to a shift in phase of the Interdecadal Pacific Oscillation. Annual peak flows, and annual minimum flows averaged over 28 days, for two periods, 1947-1977 and 1978-1999, were compared using box plots and statistical tests. The plots and the tests show that a decrease of flood size has occurred since 1978 in the Bay of Plenty region of the North Island, and that increases in flood size and low-flow magnitude have occurred in the South Island for most rivers with headwaters draining from the main divide of the Southern Alps and Southland. For much of the North Island apart from the Bay of Plenty, and the north of the South Island, no consistent pattern of shifts was identified.

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“…Many studies have found that climate change and ENSO events might increase the magnitude and frequency of droughts and low river flows in some areas of the world (Jones, 1999), including parts of North America (Woolhiser et al, 1993;Piechota et al, 1997;Westmacott & Burn, 1997;Nigam et al, 1999;EOS, 2000), Europe (Sefton & Boorman, 1997), and Australasia (Burn, 1994;Moss et al, 1994;Mullan, 1996;McKerchar et al, 1998;Chiew et al, 1998;Mosley, 2000).…”

Section: Introductionmentioning

confidence: 99%

Regional river flow, water quality, aquatic ecological impacts and recovery from drought

Caruso¹

2001

Hydrological Sciences Journal

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During severe drought and low flows in the Otago Region of the South Island of New Zealand, increased bacterial contamination of rivers occurred in agricultural/ pastoral catchments due to greater stock use of waterways and the lack of dilution and flushing flows. Concentrations and loadings of nitrogen and phosphorus generally decreased due to the lack of rainfall, runoff and transport from diffuse sources. Other analytes, including dissolved solids and pH, did not change to any considerable degree and were quite spatially variable. Although the health of benthic macroinvertebrate communities can decrease with a lower diversity and fewer sensitive taxa, effects were not significant in most rivers. Algal blooms occurred in some locations, particularly in lowland agricultural catchments with low water velocities and little shade. The prolonged lack of flushing flows can be a significant problem. Fish kills occurred where they became stranded and isolated from the main flow and where there was a lack of deeper pool refuges. Temperatures in excess of 25°C can also result in isolated fish kills, but the duration of these high temperatures appears to be the most critical factor. Adverse effects from drought can be widespread and severe in some locations, but appear to be relatively short-lived with recovery occurring rapidly with increasing flows at most locations. This indicates a degree of resilience of rivers to drought and low flows with long-term impacts that are not severe.Key words rivers; low flows; drought; water quality; aquatic ecology; New Zealand Impacts de la sécheresse, puis restauration, sur les écoulements régionaux, la qualité de l'eau et l'écologie aquatique Bien que la santé des communautés de macro-invertébrés benthiques puisse être dégradée avec une diminution de la diversité et une sélection des taxons les plus robustes, les effets ont été peu significatifs dant la plupart des rivières. Des pullulations algales ont eu lieu en certains endroits, en particulier dans des bassins versants agricoles de plaines, présentant des vitesses d'écoulement faibles et peu d'ombre. L'absence durable de débit de chasse peut être un problème important. La mortalité des poissons a été forte là où ils se sont trouvé piégés et isolés des cours d'eau principaux et où les refuges profonds manquaient. Des températures supérieures à 25°C peuvent également causer la mort des poissons isolés, mais la durée de ces fortes températures apparaît comme le facteur critique principal. Les effets négatifs de la sécheresse peuvent être étendus et sévères en certains lieux, mais sont relativement éphémères dans la mesure où les qualités sont rétablies rapidement après la reprise des écoulements. Cela indique une forte resilience des rivières par rapport à la sécheresse et aux étiages, et donc des impacts à long terme qui ne sont pas sévères.

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Dependency of summer lake inflows and precipitation on spring SOI

Cited by 45 publications

References 7 publications

Long‐term trend analysis for precipitation in Asian Pacific FRIEND river basins

Long‐term trend analysis for precipitation in Asian Pacific FRIEND river basins

Shifts in flood and low-flow regimes in New Zealand due to interdecadal climate variations

Regional river flow, water quality, aquatic ecological impacts and recovery from drought

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