Identifying Opportunities for Climate Adaptation in the Delaware Estuary (CAKE)

Background

The Delaware Estuary, spanning Delaware, Pennsylvania, and New Jersey, provides critical habitat for fish and wildlife, and drinking water, recreation, and food for residents. In addition, the estuary hosts the largest freshwater port in the world and five of the largest refineries on the east coast of the United States. The PDE was selected as one of the six pilot projects under the EPA’s Climate Ready Estuaries Program, receiving grants in 2008 and 2009 to support these efforts. PDE had many collaborators on this project, including the Academy of Natural Sciences, Delaware River Basin Commission, and U.S. Geological Survey. A Climate Adaptation Work Group was also set up to oversee technical elements. PDE worked with partners to examine three case studies focused on human impacts (drinking water), habitat (tidal wetlands), and living resources (shellfish) in order to assess the resources’ vulnerability to climate change. Impacts of particular concern for the area are sea level rise, salinity rise, increases in temperature, altered rainfall, and increased storms. For each of the three resources—drinking water, tidal wetlands, and shellfish—project leads conducted an inventory of project climate change impacts, identified data gaps, and identified and prioritized management options.

Implementation

Drinking water, tidal wetlands, and shellfish were selected as case study topics because of their ecological and societal importance to the region: 

1. The estuary and surrounding watersheds provide potable drinking water for over 16 million people in the region. The availability of clean drinking water in the face of climate change impacts is threatened by increased salinity because many of the water intakes are from the tidal freshwater area; compounding factors include population growth, development, and alterations to freshwater flow. Project leads investigated potential vulnerabilities to drinking water supplies in the area.
2. Tidal wetlands play an important role throughout the estuary as habitat and regulators of water quality and flooding events. This habitat is presently degraded and is further threatened by sea level rise, salinity, temperature, sedimentation, freshwater input, and flooding. This project quantified the value of the ecosystem services that tidal marshes provide.
3. Bivalve shellfish are at risk in the estuary and its watershed. Scientists researched and modeled vulnerabilities to different both freshwater and marine species and compared potential adaptation options. Shellfish are commercially and ecologically viable in the region and are threatened by increased salinity, decreased water quality, warmer temperatures, disease, and non-native and invasive species introductions, among other factors. 

Example adaptation recommendations included: 

• Protecting vulnerable drinking water infrastructure;
• Developing and funding a climate monitoring program;
• Identifying priority tidal wetland areas for restoration and protection;
• Educating the management community about key Delaware Estuary resources; and
• Considering policy changes needed to facilitate climate change adaptation.

Citation

Gregg, R. M. (2021). Identifying Opportunities for Climate Adaptation in the Delaware Estuary [Case study on a project of the Partnership for the Delaware Estuary]. Version 2.0. Product of EcoAdapt’s State of Adaptation Program. Retrieved from CAKE: https://www.cakex.org/case-studies/identifying-opportunities-climate-adaptation-delaware-estuary (Last updated October 2021)

This case study was originally published on the EcoAdapt Climate Adaptation Knowledge Exchange.