Najjar approached Penn State's IT department, where he learned that veteran staffer Mike Loewen had a private collection of vintage computer equipment - including, luckily, a boxy contraption called a Documation M1000-L card reader.
Using plans he found online, Loewen also had built a USB interface so data from the card-reader could be transmitted to a modern computer running Windows software.
Najjar showed up with his cards at Loewen's house in State College, and an hour and a half later, presto! Column after column of historical data on the vast body of water between New Jersey and Pennsylvania.
"Amazingly, it worked the first time," said Loewen, whose day job includes maintaining the system that tracks the hours of wage-payroll employees at Penn State.
The card-reading happened in 2009, but it was only this year that Najjar's student Andrew Ross used the data to complete his master's thesis.
Ross analyzed the punch-card data, from Rutgers' Haskin Shellfish Research Laboratory, as well as more recent figures from the U.S. Geological Survey. He found that salinity in the estuary was largely unchanged.
However, using statistical models, Ross determined that the bay would have become saltier if not for the offsetting effect of increased stream flow.
The increase in salinity could well be due to rising sea levels, but other factors may be involved, and more research is needed, Najjar said.
In the mid-Atlantic region, sea levels are rising because of several factors: the melting of glaciers and other land-based ice, the fact that water expands as it warms, and that the land is sinking.
The bay's salinity affects industry, everyday folks, and wildlife. Salt can spell corrosion for industrial intake pipes, for example. And one type of disease that strikes oysters becomes more prevalent in saltier water.
The Delaware is also a source of drinking water for Philadelphia and beyond, though for now, water intakes are situated far upriver from the "salt line" - the point beyond which water is considered too salty to drink. The research was funded by the National Science Foundation and the Partnership for the Delaware Estuary.
If any of Najjar's future research requires reading punch cards, Loewen stands ready to help. His computer collection contains dozens of other machines besides the card reader, including some of the earliest not-so-light "portable" computers - Loewen calls them "luggables" - and an IMSAI 8080, the type of computer used in the 1983 Matthew Broderick movie WarGames.
He is also building a life-size replica of the robot from 1960s TV's Lost in Space - a project Najjar described as "a little bit over the top."
Plenty of others share Loewen's passion for old computers. He is a member of the Mid-Atlantic Retro Computing Hobbyists, which has its own museum in Wall, N.J.
The goal of Loewen and other members is not to preserve their vintage treasures under glass, he said.
"There's a few of them I keep up and use them quite frequently," Loewen said. "The rest I fire up once in a while for a project or to make sure they're still working."
Computers are made to be used, he said. And, when necessary, to conduct research.