Magnitude and Frequency of Floods in New York

Lumia, Richard; Freehafer, Douglas A.; Smith, Martyn J.

doi:10.3133/sir20065112

Cited by 14 publications

(17 citation statements)

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“…For the 10‐year event, regulated flow in the Upper Hudson is now about 300 m 3 /s less than prior to dam construction, and for the 100‐year event the reduction is about 800 m 3 /s. The calculated recurrence intervals were similar to previously published analyses of the predam discharge record (Lumia et al, ; Figure ). Using the relationship between discharge and water level observed prior to 1930 of 1.6 m per 1,000 m 3 /s (Figure ), the decrease in flow for the 10‐year event corresponded to a decrease in water level of 0.5 m, and the 100‐year flow event water level decreased by 1.3 m. The total decreases in water level for the 10 and 100‐year water levels at Albany (2.6 and 2.0 m, Figure ) were greater than these decreases due to flow regime alone, indicating that the net reduction in flood risk is due both to flow regulation and channel deepening in the estuary.…”

Section: Results and Interpretationsupporting

confidence: 87%

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Bigger Tides, Less Flooding: Effects of Dredging on Barotropic Dynamics in a Highly Modified Estuary

et al. 2019

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Since the late nineteenth century, channel depths have more than doubled in parts of New York Harbor and the tidal Hudson River, wetlands have been reclaimed and navigational channels widened, and river flow has been regulated. To quantify the effects of these modifications, observations and numerical simulations using historical and modern bathymetry are used to analyze changes in the barotropic dynamics. Model results and water level records for Albany (1868 to present) and New York Harbor (1844 to present) recovered from archives show that the tidal amplitude has more than doubled near the head of tides, whereas increases in the lower estuary have been slight (<10%). Channel deepening has reduced the effective drag in the upper tidal river, shifting the system from hyposynchronous (tide decaying landward) to hypersynchronous (tide amplifying). Similarly, modeling shows that coastal storm effects propagate farther landward, with a 20% increase in amplitude for a major event. In contrast, the decrease in friction with channel deepening has lowered the tidally averaged water level during discharge events, more than compensating for increased surge amplitude. Combined with river regulation that reduced peak discharges, the overall risk of extreme water levels in the upper tidal river decreased after channel construction, reducing the water level for the 10-year recurrence interval event by almost 3 m. Mean water level decreased sharply with channel modifications around 1930, and subsequent decadal variability has depended both on river discharge and sea level rise. Channel construction has only slightly altered tidal and storm surge amplitudes in the lower estuary. Plain Language SummaryDredging for navigation has deepened harbors and estuaries around the world, altering circulation patterns and tidal water levels. In the Hudson River estuary, channel construction for ports in New York Harbor and Albany more than doubled channel depths in some regions. Major dredging began in the late 1800s, so to characterize associated changes in the hydrodynamic conditions, we analyzed archival water level records and navigational charts back to that period. Water level records from Albany show that channel construction reduced the effects of friction such that the tide now amplifies in the upper estuary, more than doubling the tidal amplitude compared with before dredging. The lower friction also allows storm surge from the coast to travel farther landward. However, major flooding in the upper tidal river historically was mainly due to river discharge events, and the deeper channel allows for more effective conveyance of flood waves. Thus, despite the increases in tides and storm surge, the risk of flooding in the upper estuary decreased with construction of the navigational channel. The Hudson provides a well-documented example of how multiple anthropogenic factors can significantly influence physical processes in extensively modified estuaries. Key Points:• Archival records over the past 150 years show that the tidal amplitu...

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Section: Results and Interpretationsupporting

confidence: 87%

“…The diamond markers are unbiased return intervals based on rank‐ordered data (e.g., Makkonen, ). Return intervals calculated by the USGS for the same data prior to discharge regulation but using log‐Pearson type III and regional regression analyses (Lumia et al, ) are shown for reference.…”

Section: Results and Interpretationmentioning

confidence: 99%

Bigger Tides, Less Flooding: Effects of Dredging on Barotropic Dynamics in a Highly Modified Estuary

et al. 2019

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“…The peak flows (discharge) during the floods of August and September 2011 were estimated for each ungaged study site by scaling USGS reference stations reported peak discharge magnitude or the AEP of that discharge, using a USGS watershed characteristics database called StreamStats. StreamStats was used to delineate the ungaged drainage–basin boundary and estimate the peak flows associated with standard flood AEP (Ries, Guthrie, Rea, Steeves, & Stewart, ) using regional regression equations devised between basin characteristics and long‐term USGS discharge records, by hydro‐physiographic region (Lumia, Freehafer, & Smith, ). The flood discharge and AEP associated with the Irene and Lee storms at each ungaged site were estimated using two methods, and the most extreme values (i.e., largest discharge, smallest AEP) were used to assess relationships with changes in macroinvertebrate metrics following the floods.…”

Section: Methodsmentioning

confidence: 99%

“…The flood discharge and AEP associated with the Irene and Lee storms at each ungaged site were estimated using two methods, and the most extreme values (i.e., largest discharge, smallest AEP) were used to assess relationships with changes in macroinvertebrate metrics following the floods. The first method estimated ungaged peak discharge, Q u‐P , as the product of the ratio of watershed areas, A u /A g and the observed peak discharge, Q g‐P , where A u is the ungaged watershed area and A g is the gaged watershed area (Lumia et al, ). Then the Q u‐P was used in StreamStats to interpolate between the regional regression flood discharge values and identify the associated AEP u‐P for the ungaged peak flood.…”

Section: Methodsmentioning

confidence: 99%

Effects of extreme floods on macroinvertebrate assemblages in tributaries to the Mohawk River, New York, USA

Calderón

Baldigo

Smith

et al. 2017

River Research & Apps

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Climate change is forecast to bring more frequent and intense precipitation to New York which has motivated research into the effects of floods on stream ecosystems. Macroinvertebrate assemblages were sampled at 13 sites in the Mohawk River basin during August 2011, and again in October 2011, following historic floods caused by remnants of Hurricane Irene and Tropical Storm Lee. The annual exceedance probabilities of floods at regional flow-monitoring sites ranged from 0.5 to 0.001. Data from the first 2 surveys, and from additional surveys done during July and October 2014, were assessed to characterize the severity of flood impacts, effect of seasonality, and recovery. Indices of total taxa richness; Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness; Hilsenhoff's biotic index; per cent model affinity; and nutrient biotic index-phosphorus were combined to calculate New York State Biological Assessment Profile scores. Analysis of variance tests were used to determine if the Biological Assessment Profile, its component metrics, relative abundance, and diversity differed significantly (p ≤ .05) among the four surveys. Only total taxa richness and Shannon-Wiener diversity increased significantly, and abundance decreased significantly, following the floods. No metrics differed significantly between the July and August 2014 surveys which indicates that the differences denoted between the August and October 2011 surveys were caused by the floods. Changes in taxa richness, EPT richness, and diversity were significantly correlated with flood annual exceedance probabilities. This study increased our understanding of the resistance and resilience of benthic macroinvertebrate communities by showing that their assemblages were relatively impervious to extreme floods across the region.

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“…LP3 is the recommended distribution in the United States (typically for flood analysis), Australia, Taiwan, Pakistan, and Nigeria [52][53][54][55][56][57].…”

Section: Log-pearsonmentioning

confidence: 99%

Isohyetal Maps of Daily Maximum Rainfall for Different Return Periods for the Colombian Caribbean Region

González-Álvarez¹,

Viloria-Marimón

Coronado-Hernández

et al. 2019

Water

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In Colombia, daily maximum multiannual series are one of the main inputs for design streamflow calculation, which requires performing a rainfall frequency analysis that involves several prior steps: (a) requesting the datasets, (b) waiting for the information, (c) reviewing the datasets received for missing or data different from the requested variable, and (d) requesting the information once again if it is not correct. To tackle these setbacks, 318 rain gauges located in the Colombian Caribbean region were used to first evaluate whether or not the Gumbel distribution was indeed the most suitable by performing frequency analyses using three different distributions (Gumbel, Generalized Extreme Value (GEV), and Log-Pearson 3 (LP3)); secondly, to generate daily maximum isohyetal maps for return periods of 2, 5, 10, 20, 25, 50, and 100 years; and, lastly, to evaluate which interpolation method (IDW, spline, and ordinary kriging) works best in areas with a varying density of data points. GEV was most suitable in 47.2% of the rain gauges, while Gumbel, in spite of being widely used in Colombia, was only suitable in 34.3% of the cases. Regarding the interpolation method, better isohyetals were obtained with the IDW method. In general, the areal maximum daily rainfall estimated showed good agreement when compared to the true values.

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Magnitude and Frequency of Floods in New York

Cited by 14 publications

References 0 publications

Bigger Tides, Less Flooding: Effects of Dredging on Barotropic Dynamics in a Highly Modified Estuary

Bigger Tides, Less Flooding: Effects of Dredging on Barotropic Dynamics in a Highly Modified Estuary

Effects of extreme floods on macroinvertebrate assemblages in tributaries to the Mohawk River, New York, USA

Isohyetal Maps of Daily Maximum Rainfall for Different Return Periods for the Colombian Caribbean Region

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