Dinotopia

#2 River Quest by John Vornholt, 1995.

Thirteen-year-old Magnolia and Paddlefoot, a Lambeosaurus, are apprenticed to the Habit Partners of Freshwater. Habitat Partners keep an eye on different aspects of the environment on Dinotopia and make sure that the environment is maintained and cared for. The Habitat Partners of Freshwater are specifically concerned with the bodies and sources of freshwater all over Dinotopia.

When Magnolia’s master, Edwick, is injured badly during the eruption of a geyser, he and his partner, a Saltasaurus named Calico, retire and leave the post to Magnolia and Paddlefoot. Magnolia thinks that she is still too young for the position, and she and Paddlefoot worry about whether they are ready to handle the job. However, they have no choice because a crisis has arisen, and Edwick is in no shape to handle it.

The Polongo River, which supplies the water for the waterfalls that power virtually everything in Waterfall City, is drying up. Magnolia and Paddlefoot must journey up the river to find out what is happening and restore the river to its proper course.  Along the way, they find friends who can help them, but completing their mission means coming perilously close to the Rainy Basin where the meat-eating dinosaurs live.

The book is currently available online through Internet Archive.