Lake Iamonia area is known to have supported a variety of megafauna from as far back as 23.6 Ma. Fossils of the bear-dogAmphicyon and the dog-like Temnocyonines have been uncovered at nearby sites. The Griscom Plantation Site, once located on Luna Plantation, and on the south shore of Iamonia has produced fossils of the ruminant Leptomeryx, the horse relatives Merychippus and Parahippus leonensis, and the ancient camel Oxydactylus. Osbornodon iamonensis, a forerunner of today's dog, was named for the lake.
Prehistoric people
The lake was home to the Woodland culture, more specifically the Weeden Island culture, of early Native Americans from roughly 200 BCE to 750 AD. It was within the Apalachee Province from 1000 AD to the 1520s and later the lake would become home to the Seminoles. Lake Iamonia is pronounced "I-monia" and is named after a Seminole town “Hiamonee,” which was located on the banks of the Ochlockonee River.
Location
The lake is located in the Red Hills Region and is approximately 5,757 acres in size and is long and up to wide. It has a drainage basin of roughly 101 square miles. County Road 12 runs along the northern part of the lake. Tall Timbers Research Station and Land Conservancy is situated on a bluff on the north side of the lake. The eastern side borders near US 319, the south side is bordered by the developments of Killearn Lakes Plantation and Luna Pines. The west side edges near State Road 155. The highest elevation around the lake's basin is.
Details
Lake Iamonia is classified as oligotrophic to mesotrophic with a Hydrologic Unit Code of 31200. The eastern end of Lake Iamonia is oligotrophic which makes it one of the cleanest lakes in Leon County. The lake is above sea level and the sink basin, located on the northern shore of Lake Iamonia, has a surface area of. Its average depth is and its maximum depth is. The lake is surrounded by 4000 acres of land under conservation easement. The volume of water in the lake is affected by water in its own drainage basin and by water from the Ochlockonee River and rainfall in Southwestern Georgia. The flooding of this river re-filled the entire body of the dried lake within 3 days in February 2008. Thunderstorms which hit the Florida panhandle and southwest Georgia on April 2 and 3 brought the level of the Ochlockonee River to, above flood stage raising the lake level substantially.
Dams and dikes
In 1910, a dam was constructed across the western end sloughs with two small bridges separated by of fill dirt. The dam separated Lake Iamonia from the Ochlockonee River to keep out the river's water so that the lake would dry for agricultural purposes. In 1940 a long, wide earthen dike was constructed around the sink basin to keep water in the lake. A concretespillway was constructed for overflow with metal pipes of diameter and sluice gates built into the earthen dikes at the sink. Just before 1950 additional earthen dams were built across Cromartie Arm and Strickland Arm and bordering Horseshoe Plantation. The purpose of these dams was to keep water in Cromartie and Strickland Arms for the plantations. By the 1970s aquatic plants had increased in the lake. In 1978 the Florida Fish and Wildlife Conservation Commission constructed draw down structures in the sink basin on the north end and under the bridge on N. Meridian Road but were removed by 1980 due to damage from bald cypress roots. Northwest Florida Water Management District welded the sluice gates open and the sink drains continuously. The sink area covers and has a maximum depth of. It has a drain rate at 9.2 cubic feet per second.
