Commentary: Planning needed to tackle local impacts of climate change

By Kristen Bowman Kavanagh

The climate is changing, and the Delaware River Basin is not immune to the impacts.

The Delaware River Basin Commission (DRBC) has been working with its partners in government, academia and the nonprofit and private sectors to study how climate change will impact water resources.

Kristen Bowman Kavanagh

Because there are no dams on the Delaware River preventing salty oceanwater from mixing with the river’s freshwater, sea levels have a significant effect on both water quality and water supply. In the Delaware Estuary — where the fresh- and saltwater mix — sea levels are rising. Data shows that in the last 100 years, sea levels have risen about 14 inches (1.2 feet) in Lewes and about 12 inches (1 foot) in Philadelphia. The rate and amount at which sea levels are rising are expected to increase in the future.

In addition to sea level rise, local climate-change impacts include increased temperatures and variations in precipitation patterns, both of which will affect water supply and water quality in the basin. But how?

• Increased temperatures will affect stream water quality, turbidity levels will likely increase, and dissolved oxygen levels will decrease. These changes will also affect aquatic life such as fish, oysters and plants.

• Increased temperatures could also affect water supply by changing the seasonality of flows. For example, less snowpack in the winter will result in less snowmelt and lower flows in the spring.

• Precipitation is predicted to occur in the form of more intense rain events and more frequent dry spells. This signals a potential increase in flood events coupled with more frequent droughts.

• Sea level rise will increase salinity concentrations in the Delaware Estuary, potentially impacting drinking water intakes in areas that will include Philadelphia and Camden, New Jersey. This will increase the risks to public health and require costly modifications or additional releases from reservoir storage to ensure there is enough freshwater flowing downstream to counteract the rise in sea level.

The relative sea level trend at Lewes, Del. is 3.53 mm/year; the period of record is about 100 years, which equates to a rise in sea level of roughly 1.2 feet in 100 years.
(Graphic courtesy of tidesandcurrents.noaa.gov)

In December 2019, DRBC formed the Advisory Committee on Climate Change (ACCC). The committee’s purpose is to provide the DRBC and the basin community with scientifically based information for identifying and prioritizing threats to the basin’s water resources, as well as recommendations for mitigation, adaptation and improved resiliency.

The ACCC brings together climate scientists, researchers, planners and experts on climate-change adaptation and resiliency. Members represent government, academic and research institutions, environmental/watershed organizations, businesses/industries and water/wastewater utilities.

Representatives from the state of Delaware include the Delaware Department of Natural Resources and Environmental Control’s Dr. Robert Scarborough, Dr. Danielle Kreeger from the Partnership for the Delaware Estuary (PDE) and the Delaware Geological Survey’s John Callahan.

The ACCC held its inaugural meeting virtually in August. Its second meeting, also being held virtually, is scheduled for Dec. 17 from 9 a.m. to 12:30 p.m. and will include several presentations focused on sea level rise in the basin. We invite all those interested in learning more about climate-change impacts in the basin to join us Dec. 17.

The committee will also be hosting a one-day forum on climate change in the Delaware River Basin, as part of PDE’s biennial Science and Environmental Summit, on March 2.

Please visit nj.gov/drbc/about/advisory/ACCC_index.html for for committee information, details on how to participate Dec. 17 and a link to learn more about the PDE summit.

DRBC’s advisory committees provide a forum for the exchange of information and viewpoints on a variety of issues, enhancing communication and coordination. All meetings of DRBC’s advisory committees are open to the public.

Kristen Bowman Kavanagh, PE, has been the deputy executive director of the Delaware River Basin Commission since 2019 and is the liaison for the Advisory Committee on Climate Change. Learn more about the DRBC at drbc.gov.