Join Lake County Water Authority naturalists on a hike of Hidden Waters Preserve in Eustis on April 11 at 9 a.m. Be prepared for a strenuous hike, since the change in elevation on this 90-acre property is approximately 105 feet. Tour guides will showcase the unique features of this property, which consists of uplands, a ravine, a creek and a sinkhole lake. LCWA acquired the site in 1996 and has been restoring the uplands areas, which were at different times a citrus grove and a golf course, as well as a dumping ground for trash. Restoration has provided excellent habitat for gopher tortoises and other animals, and much of the restoration involves the establishment of  longleaf pine and native Florida wildflowers. Space is limited to 15 hikers, and reservations are required. Call 352-324-6141, ext. 0.