The rice trunk was an ingenious, yet simple apparatus that made large-scale planting and irrigation control possible in the South Carolina lowcountry. Rice trunks are wooden sluices installed in “banks” or dikes of rice fields for irrigation or flood control. They are long, narrow, wooden boxes made of thick planks, and each has a door at each end. Hung on uprights, the swinging doors, called gates, may be raised or lowered to drain or flood a field. When the gate on the river end of a trunk is raised, the water in the field runs into the river at low tide. As the tide turns, the rising water exerts pressure on the river gate and swings it tightly shut, preventing water from returning to the field. To flood the field, the process is reversed.
It is possible that early settlers who had seen trunks used in the freshwater marshes of England brought the practice to America. As early as the thirteenth century, both the English and the French used tide-operated mills for grinding grain. Swinging gates allowed the incoming tide to flood ponds, and when the tide turned, the pressure of the water inside automatically closed the gates. When the pond was full, the miller opened the gates and escaping water drove the mill wheels. Before the advent of steam, South Carolina planters also used tide-operated rice mills.
In the early colonial period, planters used hollow cypress logs, each with a vertical plug at one end, as sluices. David Doar, rice planter and historian, believed that this practice was the origin of the term “trunk.” In rice fields located in West African mangrove swamps it was customary to use tree trunks with plugs, and it seems evident that Africans brought this method of controlling irrigation to America. Archaeology at Drayton Hall plantation near Charleston in 1996 revealed an intermediate form that indicated a step in evolution from the plug trunk to the hanging gate sluice. Dating to the early 1800s, the excavated device was a sixteen-foot-long wooden box, about two feet wide and twelve inches high, with grooved ends containing a rectangular gate that moved up and down to control the flow of water. The rice historian Judith Carney called the Drayton gate “the hybridized product of both African and European inventiveness.”
Carney, Judith A. Black Rice: The African Origins of Rice Cultivation in the Americas. Cambridge: Harvard University Press, 2001.
Chaplin, Joyce E. An Anxious Pursuit: Agricultural Innovation and Modernity in the Lower South, 1730–1815. Chapel Hill: University of North Carolina Press, 1993.
Doar, David. Rice and Rice Planting in the South Carolina Low Country. 1936. Reprint, Charleston, S.C.: Charleston Museum, 1970.
Heyward, Duncan Clinch. Seed from Madagascar. 1937. Reprint, Columbia: University of South Carolina Press, 1993.