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Climate and human impacts on hydrological processes and flood risk in southern Louisiana
  • +6
  • Augusto Getirana,
  • Kumar Sujay,
  • Goutam Konapala,
  • Wanshu Nie,
  • Kim A locke,
  • Bryant D Loomis,
  • Charon Birkett,
  • martina ricko,
  • Simard Marc
Augusto Getirana
NASA GSFC

Corresponding Author:[email protected]

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Kumar Sujay
NASA GSFC
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Goutam Konapala
Goddard Space Flight Center
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Wanshu Nie
Johns Hopkins University
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Kim A locke
NASA GSFC
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Bryant D Loomis
NASA GSFC
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Charon Birkett
NASA/GSFC
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martina ricko
NASA Goddard Space Flight Center
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Simard Marc
Caltech/Jet Propulsion Laboratory
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Abstract

Satellite observations of coastal Louisiana indicate an overall land loss over recent decades, which could be attributed to climate- and human-induced factors, including sea level rise (SLR). Climate-induced hydrological change (CHC) has impacted the way flood control structures are used, altering the spatiotemporal water distribution. Based on “what-if” scenarios, we determine relative impacts of SLR and CHC on increased flood risk over southern Louisiana and examine the role of water management via flood control structures in mitigating flood risk over the region. Our findings show that CHC has increased flood risk over the past 28 years. The number of affected people increases as extreme hydrological events become more exceptional. Water management reduces flood risk to urban areas and croplands, especially during exceptional hydrological events. For example, currently (i.e., 2016-2020 period), CHC-induced flooding puts an additional 73km2 of cropland under flood risk at least half of the time (median flood event) and 65km2 once a year (annual flood event), when compared to a past period (1993-1997). A ten- to twenty-fold increase relative to SLR-induced flooding. CHC also increases population vulnerability in southern Louisiana to flooding; additional 9900 residents currently live under flood risk at least half of the time, and that number increases to 27,400 for annual flood events. Residents vulnerable to SLR-induced flooding is lower (6000 and 3300 residents, respectively). Conclusions are that CHC is a major factor that should be accounted for flood resilience and that water management interventions can mitigate risks to human life and activities.