Sally Bethea of the Upper Chattahoochee Riverkeeper will speak on the topic of "The Chattahoochee River Watershed" as the first of the Elachee Nature Science Center's new winter lecture series at 7 p.m. Jan. 26.

The event is set for the fourth Thursday each month through March.

Bethea is the founding director of the Riverkeeper, a 5,000-member nonprofit environmental advocacy organization whose mission is to protect and restore the Chattahoochee River, its tributaries and watershed.

She has 30 years of experience in environmental issues and has served on the national boards of Waterkeeper Alliance and River Network, and the Georgia Board of Natural Resources (1999-2007).

Admission is $5 for nonmembers, with Elachee members admitted free. Call 770-535-1976 for reservations.

The center is located at 2125 Elachee Drive, Gainesville.

Other lectures in the series will include "Winter Hummingbirds in Georgia" and "Endangered Plants of Georgia."