Parts of the Susquehanna River turned bright green yesterday - and it wasn't even St. Patrick's Day.
The colorful water came from a dye that was dumped into a tributary as part of a study to track water flow in the lower Susquehanna.
"If there is a spill, it will help us know how long it would take for pollutants or chemicals to make it down here and what happens downstream," said Susan Obleski, director of communications for the Susquehanna River Basin Commission, which is performing the test for the Maryland Department of the Environment.
The study also is being carried out to comply with a federal law requiring states to assess sources of public drinking water. The Susquehanna provides drinking water to surrounding areas and, during last year's drought, also was a source for the Baltimore metropolitan area.
Yesterday, as the fluorescent water tumbled amid rocks and eddies upstream, a group of official water-watchers and testers gathered along the river bank in the mist, waiting for the first droplets to make their way to the Port Deposit Water Treatment Plant in Cecil County.
The Port Deposit facility was the first intake plant along the dyed water's route. A short canoe ride from shore, old wooden pilings mark where two 16-inch pipes draw in water, funneling it to a 20-foot well inside the brick plant.
"This is a key one," said Dave Heicher, chief of the commission's water quality and monitoring programs. "It will help us know what to expect."
After being monitored at Port Deposit, the dye, which can be detected in concentrations of less than one part per billion, was to be sampled throughout the day at four other locations: the Perryville Water Treatment Plant and the Perry Point Veterans Affairs Hospital in Cecil County, and the Harford County Water Treatment Plant and Havre de Grace Water Treatment Plant, both in Harford.
Since the lower Susquehanna overflowed its banks in the winter flood of 1996, water plant operators make sure they stay in contact.
"The lines of communication between the [Conowingo] dam and towns has improved," said Chris McAfee, superintendent of the Port Deposit water plant. "We don't just work together. We're friends." The dam helps regulate water flow in the lower Susquehanna.
The day started early for the testers, with 12 pounds of fluorescein dye - a coloring agent used in some eye exams - be- ing mixed with stream water in two 55-gallon drums.
The first burst of vibrant color slowly dissipated shortly after the mixture was poured into Octoraro Creek - a Susquehanna tributary - at 8:15 a.m. and began flowing the quarter mile downstream into the river below the Conowingo Dam, observers said.
Because the river flows slowly this time of year, Obleski said, the dyewould take about eight hours to travel to Port Deposit.
The study is to continue next year, beginning in the spring.