A rice trunk, based on the centuries-old practice of using hollow tree trunks to carry water in and out of rice fields, is used here to manage marshes as wildlife habitat. Since the 1930s, when conservationists Archer and Anna Hyatt Huntington created freshwater ponds out of salt marshes, this property has been a haven for migratory waterfowl and other wild animals. With funding support from the Coastal Program of the U.S. Fish and Wildlife Service, rice trunks now allow managers to optimize the mix of saltwater and freshwater to benefit wildlife. Adding saltwater encourages widgeon grass, an important source of nutrition for water birds, and introduces baby sea creatures into the food chain. After heavy rains, draining excess pond water creates shallows where wading birds feed and alligators bask. Historically, rice trunks connected plantation fields to tidal rivers. To flood a rice field, the gate on the river was raised at high tide, allowing water to flow through the rice trunk, push open the swinging field gate, and cover the field. To drain the field, slaves reversed the process, raising the field gate at low tide so water flowed back through the rice trunk, pushed open the river gate, and escaped into the river. Today, Huntington Beach uses these same principles to admit salty sea water into the freshwater pond or to release freshwater into the marsh.