Respostas das lentes de água doce em atóis a submersões provocadas por marés ciclónicas nas Ilhas Cook do Norte

Terry, James P.; Falkland, A.

doi:10.1007/s10040-009-0544-x

Cited by 124 publications

(112 citation statements)

References 16 publications

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“…However, Yang et al (2013) used a fully coupled subsurface and surface approach that simulated tidal activity, coastal flow dynamics, and a hypothetical storm surge on a coastal aquifer. All models indicate initial salt contamination of the freshwater lens, which recovers to fresh concentrations over time due to freshwater recharging at surface and densitydriven downward migration of salt water (Terry and Falkland, 2010). The occurrence of multiple storm surges (Anderson, 2002) and accumulations of salt water at the surface in low depressions may increase the time for recovery of the lens.…”

Section: Introductionmentioning

confidence: 99%

“…Projected changes in the frequency of hurricanes and tropical storms are uncertain (IPCC -Intergovernmental Panel on Climate Change, 2014); however, there is evidence to suggest that storms may become more intense, increasing the likelihood of storm surge occurrence (Biasutti et al, 2012). Storm surge overwash can lead to salt contamination of the freshwater lens and a temporary loss of freshwater (Anderson, 2002;Illangasekare et al, 2006;Terry and Falkland, 2010). Due to topography, low-lying islands are more susceptible to saltwater inundation from sea level rise and storm surge overwash.…”

Section: Introductionmentioning

confidence: 99%

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From days to decades: numerical modelling of freshwater lens response to climate change stressors on small low-lying islands

Holding

Allen²

2015

Hydrol. Earth Syst. Sci.

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Abstract. Freshwater lenses on small islands are vulnerable to many climate change-related stressors, which can act over relatively long time periods, on the order of decades (e.g., sea level rise, changes in recharge), or short time periods, such as days (storm surge overwash). This study evaluates the response of the freshwater lens on a small lowlying island to various stressors. To account for the varying temporal and spatial scales of the stressors, two different density-dependent flow and solute transport codes are used: SEAWAT (saturated) and HydroGeoSphere (unsaturated/saturated). The study site is Andros Island in the Bahamas, which is characteristic of other low-lying carbonate islands in the Caribbean and Pacific regions. In addition to projected sea level rise and reduced recharge under future climate change, Andros Island experienced a storm surge overwash event during Hurricane Francis in 2004, which contaminated the main wellfield. Simulations of reduced recharge result in a greater loss of freshwater lens volume (up to 19 %), while sea level rise contributes a lower volume loss (up to 5 %) due to the flux-controlled conceptualization of Andros Island, which limits the impact of sea level rise. Reduced recharge and sea level rise were simulated as incremental instantaneous shifts. The lens responds relatively quickly to these stressors, within 0.5 to 3 years, with response time increasing as the magnitude of the stressor increases. Simulations of the storm surge overwash indicate that the freshwater lens recovers over time; however, prompt remedial action can restore the lens to potable concentrations up to 1 month sooner.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

From days to decades: numerical modelling of freshwater lens response to climate change stressors on small low-lying islands

Holding

Allen²

2015

Hydrol. Earth Syst. Sci.

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“…Consequently, concurrent high wave events and spring tides leading to island overwash and seawater flooding occur with little warning [48]. Although the overwash event recorded in this study caused conductivity (salinity) increases that recovered after approximately one month (Figure 8) in affected groundwater wells, more severe overwash events have the potential to be catastrophic, leading to FWL recovery times of 22-26 months [11][12][13]. For example, in 2008, 2009, and 2011, storm-driven large wave events that coincided with high tides negatively affected freshwater drinking supplies, destroyed vital crops, demolished infrastructure, and killed hundreds of thousands of Federally-protected animal species on Pacific atolls [12,66], highlighting the exceptional vulnerability of these low-lying island communities.…”

Section: Discussionmentioning

confidence: 80%

“…A number of threats to the FWLs have been identified, including: (a) infiltration of anthropogenic contaminants [5]; (b) upconing of saline water due to excessive freshwater pumping [6]; (c) reduction in reef and island size due to coastal erosion, leading in turn to a reduction in the size of the FWL [7]; (d) droughts that hinder successful recharge of the FWLs [5,[8][9][10]; and (e) storm surges that cause large waves to wash over the atolls resulting in saline intrusion [11][12][13]. Nonetheless, a better understanding of the processes that influence these FWLs-especially in light of expected climate change scenarios on low-lying atoll islands is essential to better assess atoll water resources management challenges in the near future.…”

Section: Introductionmentioning

confidence: 99%

Atoll Groundwater Movement and Its Response to Climatic and Sea-Level Fluctuations

Oberle

Swarzenski

Storlazzi

2017

Water

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Groundwater resources of low-lying atoll islands are threatened due to short-term and long-term changes in rainfall, wave climate, and sea level. A better understanding of how these forcings affect the limited groundwater resources was explored on Roi-Namur in the Republic of the Marshall Islands. As part of a 16-month study, a rarely recorded island-overwash event occurred and the island's aquifer's response was measured. The findings suggest that small-scale overwash events cause an increase in salinity of the freshwater lens that returns to pre-overwash conditions within one month. The overwash event is addressed in the context of climate-related local sea-level change, which suggests that overwash events and associated degradations in freshwater resources are likely to increase in severity in the future due to projected rises in sea level. Other forcings, such as severe rainfall events, were shown to have caused a sudden freshening of the aquifer, with salinity levels retuning to pre-rainfall levels within three months. Tidal forcing of the freshwater lens was observed in electrical resistivity profiles, high-resolution conductivity, groundwater-level well measurements and through submarine groundwater discharge calculations. Depth-specific geochemical pore water measurements further assessed and confirmed the distinct boundaries between fresh and saline water masses in the aquifer. The identification of the freshwater lens' saline boundaries is essential for a quantitative evaluation of the aquifers freshwater resources and help understand how these resources may be impacted by climate change and anthropogenic activities.

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“…Aquifer recharge is sensitive to changes in temperature and precipitation, and rising sea levels and saltwater overwash from storm surges can contribute to saline intrusion into groundwater (Post and Abarca, 2010;Terry and Falkland, 2010;White and Falkland, 2010; see also Section 29.3.2, Table 18-8). However, groundwater extraction for coastal settlements and agriculture is the main cause for widely observed groundwater degradation in coastal aquifers (e.g., White et al, 2007a;Barlow and Reichard, 2010).…”

Section: Shoreline Erosion and Other Coastal Processesmentioning

confidence: 99%

Detection and Attribution of Observed Impacts

Crämer¹,

Yohe²,

Auffhammer³

et al.

Climate Change 2014 Impacts, Adaptation, and Vulnerability

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Respostas das lentes de água doce em atóis a submersões provocadas por marés ciclónicas nas Ilhas Cook do Norte

Cited by 124 publications

References 16 publications

From days to decades: numerical modelling of freshwater lens response to climate change stressors on small low-lying islands

From days to decades: numerical modelling of freshwater lens response to climate change stressors on small low-lying islands

Atoll Groundwater Movement and Its Response to Climatic and Sea-Level Fluctuations

Detection and Attribution of Observed Impacts

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