Trends in floods and low flows in the United States: impact of spatial correlation

Douglas, Ellen; Vogel, Richard M.; Kroll, Charles N.

doi:10.1016/s0022-1694(00)00336-x

Cited by 985 publications

(735 citation statements)

References 21 publications

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“…(2) (after Hirsch and Slack, 1984). For cases the sample size n is larger than 10, the standard normal variate p is computed by using the following equation (see Douglas et al, 2000)…”

Section: Trends In Rainfall and Stream Flowmentioning

confidence: 99%

Changes in land cover, rainfall and stream flow in Upper Gilgel Abbay catchment, Blue Nile basin – Ethiopia

Rientjes

Haile

Kebede

et al. 2011

Hydrol. Earth Syst. Sci.

170

140

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Abstract. In this study we evaluated changes in land cover and rainfall in the Upper Gilgel Abbay catchment in the Upper Blue Nile basin and how changes affected stream flow in terms of annual flow, high flows and low flows. Land cover change assessment was through classification analysis of remote sensing based land cover data while assessments on rainfall and stream flow data are by statistical analysis. Results of the supervised land cover classification analysis indicated that 50.9 % and 16.7 % of the catchment area was covered by forest in 1973 and 2001, respectively. This significant decrease in forest cover is mainly due to expansion of agricultural land.By use of a change detection procedure, three periods were identified for which changes in rainfall and stream flow were analyzed. Rainfall was analyzed at monthly base by use of the Mann-Kendall test statistic and results indicated a statistically significant, decreasing trend for most months of the year. However, for the wet season months of June, July and August rainfall has increased. In the period 1973-2005, the annual flow of the catchment decreased by 12.1 %. Low flow and high flow at daily base were analyzed by a low flow and a high flow index that is based on a 95 % and 5 % exceedance probability. Results of the low flow index indicated decreases of 18.1 % and 66.6 % for the periods 1982-2000 and 2001-2005 respectively. Results of high flows indicated an increase of 7.6 % and 46.6 % for the same periods. In this study it is concluded that over the period 1973-2005 stream flow has changed in the Gilgel Abbay catchment by changes in land cover and changes in rainfall.

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“…(2) (after Hirsch and Slack, 1984). For cases the sample size n is larger than 10, the standard normal variate p is computed by using the following equation (see Douglas et al, 2000)…”

Section: Trends In Rainfall and Stream Flowmentioning

confidence: 99%

Changes in land cover, rainfall and stream flow in Upper Gilgel Abbay catchment, Blue Nile basin – Ethiopia

Rientjes

Haile

Kebede

et al. 2011

Hydrol. Earth Syst. Sci.

170

140

View full text Add to dashboard Cite

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“…These include work in the US (Lins and Slack, 1999;Douglas et al, 2000), Scandinavia (Lindstrom and Bergstrom, 2004), Canada (Zhang et al, 2001;Burn and Hag Elnur, 2002;Yue and Wang, 2002) and more recently, a global assessment by Svensson et al (2005). These studies present evidence of significant variability, but there are many inherent obstacles to attributing observed trends to climate change.…”

Section: Introductionmentioning

confidence: 99%

An assessment of trends in UK runoff and low flows using a network of undisturbed catchments

2006

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In many parts of the world attempts to discern climatic-driven changes in river flow patterns are hindered by the combined impact of other, more direct anthropogenic disturbances such as abstraction and impoundments. This study capitalises on a newly defined 'benchmark' network of natural catchments in the UK to discern natural variability in flow regimes. Trend tests were applied to time series of runoff and indicators of low-flow magnitude and duration for two study periods to assess the sensitivity of trends to the frame of reference over which tests were conducted. Notwithstanding the volatility of the recent past, the results demonstrate a general stability in runoff and low flows since the early 1960s. The strongest signal to emerge from the study is a positive runoff trend for catchments in Scotland, which was resilient to the effect of the study periods. There was also some indication of increasing runoff in maritime western areas of England and Wales. These increases in maritime areas are likely to reflect the dominance of westerly airflows in the recent past, associated with an increase in the North Atlantic Oscillation (NAO) Index. For low flows, there were no compelling trends -significant positive trends over the 1973-2002 period are influenced by a sequence of notably dry years at the start of the period and were not observed over a 40-year time-frame. There are some indications of a tendency towards decreasing low flows in some eastern catchments, but this is supported by few significant results. The results of this study provide a baseline against which to assess longer-term change from historical flow time series and to monitor future change in the benchmark network.

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“…The most widely used approaches are based on the Bonferroni equality (Simes, 1986) or modifications of that test (e.g., Rice, 1989;Benjamini and Hochberg, 1995). Other MCPs used in the fields of climate and hydrology include the field significance tests introduced by Livezey and Chen (1983), Vogel and Kroll (1989), and Douglas et al (2000). Field significance is the collective significance of a group of hypothesis tests.…”

Section: Field Significance Tests For the Uniform Distributionmentioning

confidence: 99%

Goodness of Fit of Probability Distributions for Sightings as Species Approach Extinction

et al. 2009

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Estimating the probability that a species is extinct and the timing of extinctions is useful in biological fields ranging from paleoecology to conservation biology. Various statistical methods have been introduced to infer the time of extinction and extinction probability from a series of individual sightings. There is little evidence, however, as to which of these models provide adequate fit to actual sighting records. We use L-moment diagrams and probability plot correlation coefficient (PPCC) hypothesis tests to evaluate the goodness of fit of various probabilistic models to sighting data collected for a set of North American and Hawaiian bird populations that have either gone extinct, or are suspected of having gone extinct, during the past 150 years. For our data, the uniform, truncated exponential, and generalized Pareto models performed moderately well, but the Weibull model performed poorly. Of the acceptable models, the uniform distribution performed best based on PPCC goodness of fit comparisons and sequential Bonferroni-type tests. Further analyses using field significance tests suggest that although the uniform distribution is the best of those considered, additional work remains to evaluate the truncated exponential model more fully. The methods we present here provide a framework for evaluating subsequent models.

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Trends in floods and low flows in the United States: impact of spatial correlation

Cited by 985 publications

References 21 publications

Changes in land cover, rainfall and stream flow in Upper Gilgel Abbay catchment, Blue Nile basin – Ethiopia

Changes in land cover, rainfall and stream flow in Upper Gilgel Abbay catchment, Blue Nile basin – Ethiopia

An assessment of trends in UK runoff and low flows using a network of undisturbed catchments

Goodness of Fit of Probability Distributions for Sightings as Species Approach Extinction

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