This map identifies land in the Upper Midwestern United States that has a high probability of being suitable for controlled drainage (CD).  The soils have been identified as likely to be or have been drained for crop production.  And for economic feasibility, the identified land is relatively flat to maximize the spatial area controlled by each water control structure.  The data sources are  the United States Department of Agriculture: 2017 gSSURGO data from the Natural Resources Conservation Service (USDA-NRCS) and the 2015 Cropland Data Layer from the National Agricultural Statistics Service (USDA-NASS).

The NRCS query that is mapped represents the following:

• Flat topography (1% slope or less)
• Soils that have a seasonal high water table (saturated to within 18 inches (46 cm) of the surface during the growing season)
• Cropland land use
• 15 acres or more of contiguous surface area (to represent economic feasibility)

This map is designed to give a broad picture of the locations in the region that are likely to be involved in CD activities to a greater extent.  The map does not take into account property boundaries, and the fact that land owners and managers on neighboring properties may have different goals and objectives that may not include CD.  Also, areas that are not identified in this map may actually be suitable for CD, depending on the site specific topography, drainage system layout, and other factors.  The map utilizes data that are intended for use at a broad scale, rather than a site specific scale, so field verification of the suitability of any site is still needed when evaluating potential projects.