For Immediate Release

October 3, 2024

(West Trenton, N.J.)-- The Delaware River Basin Commission (DRBC) announces the publication of A Pathway for Continued Restoration: Improving Dissolved Oxygen in the Delaware River Estuary and related modeling reports that support updating designated uses and associated water quality standards in the Delaware River Estuary to better support fish populations.

"These reports collectively illuminate the path forward to an Estuary that better supports all life stages and species of resident and migratory fish in this river, including the endangered Atlantic Sturgeon," said DRBC Executive Director Steve Tambini. "I am proud of the groundbreaking science developed, and the collaborative interagency efforts led, by the DRBC."

The DRBC's A Pathway for Continued Restoration: Improving Dissolved Oxygen in the Delaware River Estuary (Pathway report) is the culmination of more than five years of intensive scientific and technical work to develop and apply advanced hydrodynamic and water quality models. It finds that enhancing the dissolved oxygen conditions in a 38-mile reach of the Delaware River Estuary from Philadelphia to Wilmington is indeed feasible and will be protective of the reproduction and juvenile development of sensitive fish species, including the endangered Atlantic sturgeon.

When the DRBC was created in 1961, little or no dissolved oxygen was present in this reach of river for periods of up to six months each year. To combat this serious challenge, the DRBC in 1967 established designated aquatic life uses and associated numerical water quality criteria necessary to protect those uses. The aquatic life designated use in this part of the Estuary was set as "maintenance" (survival) of resident fish and movement of migratory fish through these waters to and from spawning areas. Today, significant improvements to water quality have been made, and fish in the Estuary are propagating (reproducing), not simply surviving and/or migrating.

The Pathway report and related studies identify municipal wastewater as the leading ongoing cause of reduced oxygen levels in this section of the Delaware River Estuary. The Pathway report shows that reducing summer ammonia loads from a relatively small number of large point-source discharges in the Estuary would significantly improve dissolved oxygen levels. The costs, benefits and water affordability considerations associated with advanced treatment upgrades at these critical facilities are explored.

To develop the Pathway report, the DRBC convened world-renowned experts to guide the staff in developing and calibrating hydrodynamic and water quality models that were used to evaluate potential dissolved oxygen improvement scenarios. The expert panel worked closely with DRBC staff to ensure the model was technically sound and based on current science.

"The model is scientifically defensible over a wide range of environmental conditions in the Delaware River Estuary," said Vic Bierman, Ph.D., of LimnoTech, DRBC consultant and liaison to the expert panel. "The model is appropriate for its intended use, which is to determine the controls on point and nonpoint sources necessary to improve dissolved oxygen to levels that better support key aquatic species."

Published in draft form in September 2022, the Pathway report and related reports have been updated based on input from DRBC's member agencies and its Water Quality Advisory Committee, and to reflect the Commission's September 2023 decision that it would not develop and promulgate revised water quality standards as it originally planned to do, in view of a December 2022 decision by the U.S. Environmental Protection Agency (EPA) to promulgate standards.

The final reports and complete information on the study are available on the DRBC's website at: https://www.nj.gov/drbc/programs/quality/designated-use.html.

In December 2022, the EPA announced it would develop updated regulations to revise the designated uses and the water quality criteria needed to protect those uses in this portion of the Delaware River Estuary. The EPA cited DRBC's scientific, engineering and modeling work as support for its determination that dissolved oxygen levels sufficient to support propagation of even the most sensitive aquatic species are attainable in these waters.

The EPA commended the DRBC and its member state agencies for the significant water quality improvements realized in the Estuary to date and for their commitment to updating existing standards. Since that date, the DRBC has played an integral role in supporting and providing resources to the EPA as that agency develops criteria. The EPA is expected to publish a final rule by the end of 2024.

DRBC scientists are currently focused on technical strategies for implementing the new standards, when finalized, to achieve the measurable water quality improvements the standards are designed to support. The DRBC is conducting this work in close cooperation with the EPA and Estuary state co-regulators.

The DRBC is a federal/interstate government agency created in 1961 by concurrent compact legislation, marking the first time that the federal government and a group of states joined together as equal partners in a river basin planning, development and regulatory agency. The five Commission members are the governors of the Basin states (Delaware, New Jersey, New York and Pennsylvania) and the commander of the U.S. Army Corps of Engineers, North Atlantic Division, who represents the federal government.

To learn more about the DRBC, please visit drbc.gov or follow DRBC on X at @drbc1961.

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Contact:

Elizabeth Brown, [email protected]

Kate Schmidt, [email protected]

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