Yazoo Basin of Mississippi Potential Natural Vegetation

The Yazoo Basin is located in northwestern Mississippi where it is bounded on the east by rolling uplands and on the west by the mainstem levee system along the Mississippi River. It is about 200 miles long, extending from Memphis to Vicksburg, and has an area of about 7,600 square miles. Except during major floods, surface water entering the Yazoo Basin arrives as precipitation or as runoff from the hills along the eastern flank of the basin. The only surface outlet is through the Yazoo River, which enters the Mississippi River at the southern end of the basin near Vicksburg. Most surface water discharge in the Yazoo River originates in the uplands along the eastern flank of the basin and is carried to the Yazoo via the Coldwater, Yocona, Tallahatchie, and Yalobusha Rivers as well as several smaller streams. Interior drainage is provided by numerous small streams that discharge to Deer Creek, the Big Sunflower River, Steele Bayou, or Bogue Phalia, which then flow to the lower Yazoo River. The pattern of drainage within the basin is generally southward, but can be quite convoluted, reflecting the influence of a complex topography dominated by abandoned meander belts of the Mississippi River.

Prior to construction of modern levees, major Mississippi River floods would have inundated most or all of the Yazoo Basin. However, modern mainstem levees that prevent Mississippi River overbank flooding do not completely eliminate the influence of the river on hydrology of the Yazoo Basin. High stages on the Mississippi River cause impeded drainage of tributary streams, which results in backwater flooding. Headwater flooding continues along internal streams in response to heavy rainfall in their source areas. Even where flooding has been drastically reduced, rainfall is sufficient to cause saturated soil conditions for extended periods in the winter and spring.