Climate Change and the Delaware Estuary: Three Case Studies in Vulnerability Assessment and Adaptation Planning

This report summarizes the major changes expected in the Delaware Estuary due to climate change as well as the threats to three key resources: tidal wetlands, drinking water and bivalve shellfish. These three resources served as case studies representative of the Estuary's habitats, human/water interaction, and living resources respectively, allowing investigation of climate change impacts and  potential adaptation strategies in the Estuary.

Each case study characterized the vulnerabilities of the resource to climate change using updated climate predictions, assessed the potential effectiveness of adaptation options to address those vulnerabilities, and developed recommendations for regional resource managers and stakeholders. These case studies are the first step in an adaptation planning process with the end goal of increasing the Estuary's resilience to climate impacts. For all three case studies, the protection and/or restoration of buffers (of various types) and the management of water flows were identified by experts as critical actions for adaptation. These case studies utilized expert surveys to assess current and potential adaptation tactics.

Researchers assessed the vulnerability of tidal wetlands to climate change impacts, concluding that tidal wetlands are most vulnerable to increases in sea-level rise, salinity, and precipitation and storms. Six adaptation options are recommended for tidal wetlands. Of these, allowing for landward migration was identified as the most promising tactic. This can be accomplished by protecting the natural buffers alongside wetlands, instituting structure setbacks, or removing structures, roads, or other improvements which may impede wetland migration. Watershed flow management, the installation of living shorelines, and construction of building dikes, bulkheads, and tide gates are other recommended adaptation tactics.

The researchers responsible for the drinking water case study identified potential damage to, and inundation of, drinking water infrastructure through flooding, sea-level rise, and storm surge as important areas for future research. Water infrastructure such as treatment plants and pumping stations is at risk from flooding and storm surges. Degraded water quality caused by runoff and saltwater intrusion is a major concern to drinking water experts. Forest protection is identified as the most important adaptation action to protect water quality. Other strategies include the utilization of green stormwater infrastructure, evaluation of drought and emergency response plans, and updating 100-year and 500-year floodplain maps.

The bivalve shellfish researchers examined the effects of five climate drivers on bivalves and identified six aspects of bivalve health for use in vulnerability assessments. The researchers named ten potential management tactics for bivalve adaptation. Of these, the top three tactics for assisting bivalve shellfish to adapt to climate change are direct restoration efforts: plant shell to restore oyster beds, propagate all bivalves  and seed new reefs/beds, and restore forested areas along streams for freshwater mussels.



Publication Date: June 2010

Authors or Affiliated Users:

  • Danielle Kreeger
  • Jennifer Adkins
  • Priscilla Cole
  • Ray Najjar
  • David Velinsky
  • Paula Conolly
  • John Kraeuter

Related Organizations:


Resource Category:

Resource Types:

  • Assessment
  • Case study

States Affected:


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