The headwaters of the St. Francis start in the Ozark and St. Francois Mountains of south eastern Missouri.  The highest peak in the state, Taum Sauk, at 1759 feet above sea level, is located on the western boundary of the watershed.  The river winds through National Forest Service land through much of its stretch in the mountains, and provides two high class whitewater rafting recreational areas, dropping as quickly as 60 feet per mile.  Right before the river drops out of the mountains into the flatter Mississippi River Alluvial Valley, it travels through the 34 sq km Lake Wappapello and the Wappepello dam, that was constructed in 1941 to help control headwater flooding along the river downstream.

After exiting Wappepello dam, the surround landscape switches from forested mountains to agricultural fields (mostly corn, cotton, rice, and soybeans), as well as some remnant bottomland hardwood forests.  The river forms the western boundary of the Missouri bootheel, serving as the boundary between Missouri and Arkansas.  As the course continues into Arkansas, Crowley's Ridge, an elongated ridge formed by windblown, glacial sediment, rises as the western boundary of the watershed. The next 30 or so miles are the portion of the watershed that I will focus my research on.  The seismic events of the early 19th century created an area of subsidence along the former river channel, deepening and widening the existing channel into an area that earned local names of the St. Francis Lake, and the Sunken Lands.  This area was resistant to over 150 years of "reclamation" of lands into agricultural uses, and has preserved a unique piece of the original bottomland hardwood and cypress swamp habitats that would have been prevalent across the entire Mississippi River valley in Missouri, Arkansas, Tennessee, Mississippi, and Louisiana.

Nearly the entire lower end of the watershed has been surrounded by a levee, separating the majority of the major tributaries from their original flow into the Sunken Land, and not meeting up with the rest of the river until many miles south.  At the southern end of my watershed, near Marked Tree, Arkansas, the majority of the flow of the river has been diverted into an artificial floodway to contain excess flows during high water events, and hold water that floods upstream from the Mississippi River that eventually collects all the rainfall from this area.

When this floodway was created, there was still a desire for a controlled amount of flow to continue down the original St Francis river.  This has created two outfalls from the Sunken Lands, one that sends water down the artificial channel, and one through the original channel, at approximately 210 feet above sea level.  After several engineering challenges with traditional water control structures on the outfall into the natural channel, a truely unique solution was install that lifts the entire flow of the river up and over the levee through a set of three siphons.  There will be more to come on the issues of two outfalls, and the control of the water level in the lake above them.

The entire watershed of the St Francis above the Sunken Lands contains fourteen 10-digit Hydrologic Water Code (HUC) watersheds from the US Geological Survey. This covers an area of approximately 2.5 million acres (the green polygon in the map.)

The focused study area for my blog will be the northern half of the Saint Francis River Floodway - Saint Francis River (HUC 802020309), bounded my the dam/levee that bisects the watershed.  This  is an area of 62,831 acres (the blue polygon in the map.)  The majority of the land in the study area is part of the St Francis Sunken Lands Wildlife Management Area that is owned by the Arkansas Game and Fish Commission, with several notable private in holdings that I will expand on later.

Take a look at the map I have created below, I have also included a link on the left hand nav to a larger version.  The menu buttons on the top right will allow you to toggle different layers on and off, as well as examine different base maps.