Most people use their GPS to get directions. On Tuesday morning, a group of fourth-graders used one to get the latitude and longitude of Donahue Memorial Park. They needed the information for Hudson River Snapshot Day.
The kids weren’t alone. There were groups scattered along both sides of the river, logging information for the Hudson River Estuary Program and the Lamont Doherty Earth Observatory.
Willow Avenue students have participated in the event since fourth-grade teacher Debbie Gilson read about it in a newspaper in 2009. She signed up for a training class, where she met Chris O’Sullivan an educator at the Trailside Museum and Zoo. The two have worked together ever since.
Snapshot Day is popular with students. They spend the day outdoors and they contribute to our knowledge of the river. People are seriously interested in what the youngsters discover. Mr. O’Sullivan calls it “citizen science.”
“For this one day,” he said, “the kids experience what a field biologist would experience.” They split into groups and moved to different stations every hour. Some groups took soil samples, while others tested the turbidity of the water.
“A muddy river may look dirty,” Mr. O’Sullivan conceded, “but it’s a good sign. It usually means that there’s life.”
We stayed with a group that noted the river’s physical characteristics. They used a stick embedded in the bottom to measure the tide. From 10 to 10:30 a.m., the water level went down by 5 centimeters. From 10:30 to 11 a.m, it decreased by 15 centimeters.
During that time, the current shifted. At the start of the day, a student tossed an orange into the Hudson and watched it float downstream. A half hour later, another orange landed in the water and for a while it floated in place — stuck between two forces, the wind and the current.
The kids took periodic temperature readings that will be compared with readings between Troy and the mouth of the river. One of the students suggested it would be cool to Face Time with another group and compare observations.
We learned a lot on this assignment, including the coordinates of Donahue Memorial Park. It can be found at 41.26 degrees north latitude and 73.59 degrees west longitude.
The Hudson Highland Land Trust helped coordinate the event.
