**3. The study area and the Little River Drainage System in Missouri**

The study area ranges from the St. Francois River in the west to the Mississippi River in the east and ranges from the headwater diversion channel at Cape Girardeau Missouri to the

A Large-Scale Wetland Conversion Project in Southeastern Missouri: Sustainability of Water and Soil http://dx.doi.org/10.5772/intechopen.81254 155

**Figure 1.** Landscape features of Southeastern Missouri.

**1. Introduction**

In the USA, it is estimated at 90% of the wetlands that existed prior to European discovery and settlement have been converted to other uses, most notably agricultural usage [1]. Land drainage has been extensive in many states, such as Alaska, Florida, Indiana, Minnesota, Missouri, and Wisconsin. Land drainage, both subsurface tile-drainage and surface drainage with and without diversionary earthworks, dramatically altered these ecosystems and their attendant soil and plant processes. Large scale and substantial changes in vegetation, water availability, nutrient flow, and other characteristics of these ecosystems impact the flora, negatively impact water quality, and reduce soil health, yet the economic impacts are important social restraints on returning these areas and regions to their pre-European settlement status.

Given that the return of thousands of hectares of cropland back to wetland status is not a pragmatic solution, current features of USA agriculture policy attempt to support best use methods that both support farm profitability and align sustainable agriculture production to

Our purpose in creating this manuscript is to chronical re-establishment of important wetland plant-soil interactive processes in converted wetlands to support soil health, water quality, environmental stewardship and biological diversity, while maintaining agricultural productivity. Although programs exist to re-create wetlands from agriculture land, there are pragmatic social, political and economic realities that limit their large-scale application. The application of emerging technologies and governmental policies, designed to support important soil attributes reflective of the original wetland status, provide opportunities for both

To be designated as "Prior Converted Cropland" in the USA, all the following land criteria must be validated: (i) cropped prior to December 23, 1985 with an agricultural commodity, (ii) cleared, drained or otherwise manipulated to make it possible to plant a crop, (iii) continued to be used for agricultural purposes, and (iv) does not flood or pond for more than 14 days during the growing season [1]. Vital wetland soil processes that need to be re-emphasized in converted wetlands include: (i) synthesis and subsequent maintenance of soil organic carbon, (ii) maintenance of soil biological diversity, including microbial populations, (iii) erosion abatement, (iv) unimpeded activity of nutrient cycles, especially the nitrogen cycle, (v) development of the original soil structure fabric, (vi) appropriate water transport within and among pedons, and (vii) encouragement of microbial-driven ecosystem processes that reduce excessive plant nutrients and degrade applied agrichemicals within suitable time frames.

**3. The study area and the Little River Drainage System in Missouri**

The study area ranges from the St. Francois River in the west to the Mississippi River in the east and ranges from the headwater diversion channel at Cape Girardeau Missouri to the

encourage soil health, organismal diversity, and environmental stewardship.

**2. Wetlands and prior converted wetlands**

154 Wetlands Management - Assessing Risk and Sustainable Solutions

environmental advancement, and agricultural profitability.

Missouri – Arkansas border (**Figure 1**). Approximately 5 million acres (2 million hectares) of landscape was drained from its status as wetlands to produce an intensive agricultural setting. The entire drainage system is maintained by taxes leveed on agricultural producers [2].

A series of north to south drainage ditches (1541 km) and levees (490 km) were constructed to transport water from southeast Missouri into Arkansas and then into the Mississippi River. The Headwater Diversion Channel was constructed to intercept drainage of the Castor and Whitewater Rivers, transporting this water eastward into the Mississippi River. Dams created the Clearwater and Wappapello Reservoirs by intercepting drainages of the St. Francois and Black Rivers, respectively [2].

### **4. Climate of Southeastern Missouri**

The climate is continental humid. The average daily January temperatures are 2 and 4°C (35 and 39°F) at Cape Girardeau and Kennett, Missouri, whereas the average summer temperatures are 25 and 26°C (77 and 79°F) at these locations. As expected, June–August are the warmest months. The growing season generally has 210-plus frost-free days. The soils are frozen only at the surface and only for brief periods of time. The rainfall is reasonably well distributed, with the total annual precipitation averaging 1.14 m at Cape Girardeau and 1.27 m at Kennett. The remnants of tropical storms from the Gulf of Mexico may provide more than 0.25 m of rainfall during a rainfall event [3].

A prominent ridge within the SLGP is called Crowley's Ridge and the Benton Hills. These elevated land masses consist on Paleozoic rocks, largely Ordovician, and are covered by Tertiary gravels and loess [6]. Crowley's Ridge and the Benton Hills bisect the SLGP, with the land mass between Ozark Escarpment and west of Crowley's Ridge and the Benton Hills called the Advance Lowlands (also called Western Morehouse Lowlands). The Advance Lowlands represent the ancestral channel of the Mississippi River and are generally composed of loamy to silty terraces and back-swamp deposits overlying glacial outwash and valley train. Conversely, the Morehouse Lowlands extend from Crowley's Ridge eastward to the Mississippi River. The Morehouse lowlands consist of terraces of varying textures, back-swamp deposits, and other alluvial environments overlying braided glacial outwash. The modern Mississippi River and its flood plain is the youngest and easternmost feature with meandering channel deposits, natural levees, silty terraces, back-swamp environments, and crevasse splay deposits that characterize the Mississippi River floodplain [7]. Sikeston Ridge and Barnes Ridge (east of Portageville, MO) are low-elevation ridges, composed of coarse-textured materials and both are in the Morehouse Lowlands. Just east of Crowley's Ridge and extending into Dunkin Co. is a terrace system of coarse-texture materials called the Kennett-Malden Prairie. The Charleston Lowland is located primarily in Mississippi Co. and consists of fine to coarse textured materials, composed to recent terrace and back-swamp environments. Between the Benton Hills and the Charleston Lowlands is the Blodgett terrace composed of coarse-textured materials and

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The study area is bordered on the west by the St. Francois River and on the east by the Mississippi River. Each of these southerly flowing river systems may alternately supply floodwaters or provide surface drainage. A series of dendritic streams and rivers drain the Black River Ozark, the Inner Ozark, and the Outer Ozark Border regions, providing surface waters to the Advance Lowlands and the Morehouse Lowlands. These rivers include: the Black River, White River, Castor River, and the St. Francois River. In addition, small streams provide drainage from the Benton Hills and Crowley's Ridge, providing water to the Advance

The dominant crops in the study area include: corn (*Zea mays* L.), soybeans (*Glycine max* (L.) Merr), cotton (*Gossypium hirsutum* L.), wheat (*Triticum aestivum* L.), and rice (*Oryza sativa* L. (indica)). Other commonly cultivated crops include: potatoes (*Solanum tuberosum* L.), sweet potatoes (*Ipomoea batatas* (L.) Lam), cowpeas (*Vigna unguiculata* (L.) Walp), winter squash (*Cucurbita sp.*), sorghum (*Sorghum bicolor* L.), watermelons (*Citrullus lanatus* (Thunb) Matsum, and Nakai), peanuts (*Arachis hypogaea* L.), and a variety of vegetable crops. The study area is the most intensively cultivated region in Missouri and having the longest growing season.

the Charleston Fan, also composed of coarse-textured materials.

**8. The value of the agricultural productivity**

**7. Drainage patterns**

and Morehouse Lowlands [8].
