Flood Prone region

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The portion of the greater watershed that I have focused on in this study is bounded on the east and west by levees.  Although Federal Emergency Management Agency flood zone maps are only partially available digitally, the area is entirely within the 100 year floodplain (1% chance of flooding in any given year). This is more than appropriate, as the majority of the area floods seasonally every late winter through early spring.  The current water management plan between the USACE and the AGFC has a goal of keeping the maximum water levels below 214' msl, as at this level, nearly 100% of the area is inundated, which displaces upland animals (especially whitetail deer and wild turkey) into the adjacent cropland.  These flood events particularly impact wild turkey, as they often occur during the nesting season in the spring.

Although the hydrology of the surrounding region has been seriously altered by ditching, channelizing, and levees, with the goal of getting the water quickly into the St. Francis River (and holding it there), floods have always been a part of this watershed.  Observing the soils in the watershed can paint a picture of the environmental conditions throughout time that lead to their development.  One attribute of particular importance to wetland habitats is hydric soils.  Hydric soils are defined by the National Resource Conservation Service as soils that formed "under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part."  In the field, these soils display observable traits, such as color changes, oxidized root channels, and iron-manganese concretions. The US Department of Argiculture produces maps of soil series, along with descriptions of their attributes (see map above).  Within the focused study area of the Sunken Lands, the vast majority of the soils are hydric (Table 1).  Other than a few small areas of high ground, more than 95% of the area in the Sunken Lands is on hydric soils, or is open water.

Map unit name	Hydric Rating	Acres in AOI	Percent of AOI
Sharkey soils, 0 to 1 percent slopes, frequently flooded	97	23,065.40	55.80%
Mhoon soils, frequently flooded	100	4,701.70	11.40%
Hayti soils	100	3,366.80	8.20%
Commerce soils, 0 to 1 percent slopes, frequently flooded	100	2,254.60	5.50%
Kobel silty clay loam, 0 to 1 percent slopes, frequently flooded	85	1,546.70	3.70%
Water	0	2,697.20	6.50%
Dundee fine sandy loam	10	519.10	1.30%
Dundee silt loam, 0 to 2 percent slopes	10	456.60	1.10%
Amagon fine sandy loam	95	419.80	1.00%
Misc Minor components		2273.47	5.50%
	Total Acres	41301.37

Table 1, Soil Series within the Sunken Lands