The Philadelphia Water Department conducted a dye test in the Delaware River between August 5 and August 8, 2014, as part of the validation process for a 3D hydrodynamic model using Environmental Fluid Dynamics Code. They are updating a flow model that will help them better understand how pollutants are dispersed in the tidal Delaware. This flow model is one of the scientific tools used in their Green City Clean Waters Plan to better protect and improve the quality of the Delaware River.
The dye chosen for this study, Fluorescein, is a green-colored fluorescent compound first synthesized in 1871. Fluorescein is the most commonly used dye for both surface and groundwater tracing studies. It is non-toxic, photodegradable, considered harmless to humans and has no environmental impacts, especially for the amounts used for this study. After injection, the dye plume was visible for approximately three hours as a light tinge of green on the surface of the water.
Turner Designs Cyclops Submersible Fluorescein Fluorometers integrated with PME Loggers were used along with other instrumentation in the Delaware River Basin Commission (DRBD) portion of the project. The deployment used one surface logger and one bottom logger, supplemented by a mobile logger that was moved from location to location.
Also involved in this test was Woods Hole Group, Inc., a world renowned oceanographic firm, directed by Rutgers University professor Robert Chant, who has performed similar projects including a recently published study occurring in the tidal Hudson River near New York City. The Delaware River Basin Commission and the US Geological Survey also participated in this survey. Several boats were used for monitoring the plume, around the clock, for the 3 days.
The Philadelphia Water Department posted some information online, along with a video describing the test and the process that took place. The website is http://phillywatersheds.org/pwd-delaware-river-dye-study
Institution: Philadelphia Water Department
Location: Delaware River