If your science teacher has kayaked from the source of the Susquehanna River to the Chesapeake Bay, you can bet that she’ll join right in when her students spend a day canoeing on the Bay’s biggest source of freshwater.

And Desiree Fox, a science teacher at Crossroads Middle School of Lewisberry, PA, did just that on a sun-drenched school day in September. Twenty Crossroads students joined her to learn about the river from Chesapeake Bay Foundation educators Tom Parke and Emily Thorpe as they paddled down the Susquehanna in canoes.

The students and adults, paddling well-used but river-worthy foundation canoes, encountered a remarkably clear but very low Susquehanna River just upriver from Harrisburg. This was the result of a very dry summer.

The “mile wide and a foot deep” Susquehanna, as it’s often described, was much less than a foot deep at several points on the paddle. Students and adults got out and pulled their watercraft over the shoals and jumped back in when the water deepened. Only one canoe tipped over — in shallow water.

The day featured, among other things, a hunt for aquatic invertebrates — animals without backbones such as water spiders, crayfish and aquatic worms. Stopping at a small island, students fanned out along the riverbank with kitchen sieves, plastic ice cube trays and other tools to capture and hold the creatures. Just what the students would find would provide a spot check on water quality.

To the apparent pleasant surprise of Tom Parke, manager of the CBF’s Susquehanna watershed environmental education program, the students found different species of invertebrates that are highly sensitive to pollution: a stonefly, gilled snail, hellgrammite and fishing spider.

“I never knew there was a spider that eats fish,” exclaimed student Jason Stewart.

The students paddled by extensive beds of submerged aquatic grasses. CBF educator Thorpe said she had never seen as much underwater vegetation until this summer. Thorpe and Park said they run educational trips almost daily except in the dead of winter.

On the banks of another island, the students learned how some American Indians in central Pennsylvania fed themselves over thousands of years: fish herding. While two students stretched a 4-foot-wide net across a patch of aquatic vegetation, the rest of the students stampeded though the water toward the net.

A few small fish turned up.

“I got to hold a fish for the first time, which was really cool,” student Summer Deardorf said after the paddle. She also saw a crayfish for the first time, which she called “pretty weird.”

The paddle ended with students standing in the water in a circle and science teacher Fox leading a discussion of the river’s environmental importance, including its value to the health of the Chesapeake Bay. CBF educators normally lead that discussion, but Parke said that Fox knows the drill.

Parke said Fox is especially qualified because she and her son have kayaked the entire length of the Susquehanna, from Cooperstown, NY, to the Bay.

Fox did not bring her kayak to the CBF event but she did bring and use her double-bladed kayak paddle.

She said she has been taking students out on the river for 12 or 13 years, after participating in a CBF teacher education course.

Not every Crossroads student gets to go on the trips. Fox said she requires that all get recommendations from three teachers and added that pupils with poor citizenship grades are not eligible.

“I don’t want to take any kids who could possibly be a problem,” Fox said.

And of course, students must have their parents’ permission.

Fox praised the foundation’s educational offerings, especially its three-day programs at Smith Island, Fox Island and the Peggy Noonan Center in Dorchester County, MD. “They are just wonderful. The students are so immersed,” she said.

The teacher said she takes one student group on the CBF one-day educational trips each fall and a second batch on the foundation’s three-day island excursions in the spring. Some of her pupils have gone on to participate in the CBF’s weeklong summer programs for high school students, she said.

Fox’s 60 students a year are among the 2,000 students who annually participate in the Bay Foundation’s Susquehanna watershed environmental education program. The program, in its 28th year, includes summer programs for teachers. “It spreads by word of mouth,” said CBF spokesman B. J. Small.

Fox figures that over the years she has personally introduced around 700 students in all to the Bay and its largest tributary.

“I like to think of all the students I have helped learn about the river and the environment,” she said.