The Lower Mississippi River Water Trail

Hurricane to Rosedale

How does a lock work? 

A lock can be thought of as an elevator to carry a vessel up or down from one pool to the next. The lock has massive fixed concrete sides and large movable metal miter gates at each end which are closed to create the equivalent of an elevator car which carries the vessel up or down using the water enclosed in the lock.  To move up the waterway from a lower elevation pool to a higher one, a vessel enters the lock chamber at the lower level with the upstream gate closed; the downstream gate closes behind the vessel after it has entered the lock.  To raise the level of the water in the lock and the vessel with it, water from the upper pool is allowed to flow by gravity into the lock through valves until it fills the lock to the same level as the upper pool. The upstream miter gate is then swung open and the vessel moves out into the upper pool.


To move a vessel from a higher elevation pool to a lower one, the procedure is reversed. With the downstream gate closed, the vessel moves into the lock chamber filled to the upper pool level, the upstream gate is closed behind the vessel, the water is permitted to drain out of the lock through valves, and the vessel is lowered with the level of the water. When the level of  water in the lock reaches that of the lower pool, the downstream miter gate is opened to allow the vessel to move out into the pool.


Contrary to what many people think, no pumps are used to fill or empty a lock; the water simply flows by gravity.  It takes about 15 minutes to fill or empty a lock chamber.  (Source: US Army Corps of Engineers)


Arkansas River: Little Rock, Fort Smith, Tulsa 

Paddlers continuing up the Arkansas will be confronted with another lock and dam ten miles upstream -- to get into the Arkansas Post Canal, and then another one three miles beyond to get into the first pool of the Arkansas River.  Continuing up the Arkansas is a series of eighteen locks & dams which make possible towboat travel all the way upstream to Tulsa, Oklahoma .  You might not have previously considered Okie towns Catoosa, Muskogee or Tulsa as port cities, but they are due to the so-called McClellan-Kerr Arkansas River Navigation System.  Paddlers on the Arkansas can access free maps by going to


White River National Wildlife Refuge 

At the downstream end of its 722-mile journey the White River flows 90 miles through White River National Wildlife Refuge, with many streams, bayous, and sloughs scattered across the refuge during high water connected to the river.  As noted above, this area looks & feels like a miniature version of the Atchafalaya River Swamp.  But there's nothing small about it.  Over 150,000 acres of protected wetlands are found here!


From their website: There are over 300 lakes and ponds located throughout White River National Wildlife Refuge. Lakes and ponds are a welcoming oasis to many animals from all types of habitats, which supply drinking water, food, a breeding place, underwater escape, and a break from insects. Wildlife you may see around this habitat are salamanders, frogs, turtles, water snakes, beavers, ducks, bald-eagles, white-tailed deer, and American black bear.  Best time for viewing is in the early morning or late afternoon, also when the weather clears after a storm.  Spring bird migration usually goes from mid-March through mid-May.  Fall migration is from September through December.


The website continues: Bottomland hardwood forests are the south's most productive living communities. In their humid, tangled depth, more than 70 species of trees grow and more kinds of flowering plants, birds, mammals, reptiles, and amphibians grow here than anywhere else in the south.  Some type of food source is always available for wildlife because bottomland hardwood forests produce acorns, berries, and seeds on differing schedules.


You can obtain a refuge map, permit, and other information by calling NWR headquarters at 870-282-8200 or visit