ABSTRACT
A 1985 U.S. Department of Agriculture (USDA) Economic Research Service economic survey showed that the states in the Midwest United States (Illinois, Indiana, Iowa, Ohio, Minnesota, Michigan, Missouri, and Wisconsin) had by that year approximately 12.5 million hectares that contained subsurface drainage systems (USDA Economic Research Service, 1987). Cropland constituted by far the large majority of this acreage. The same economic survey estimated the 1985 on-farm replacement cost for these cropland subsurface drainage systems to be $18 billion. Today, this subsurface drainage infrastructure would be worth $35 billion based on a 1986 to 2008 average yearly consumer price index ination rate of 3 percent, and this total does not include the extensive amount of drainage pipe that has been installed in the past 20 years. The magnitude of the area involved along with infrastructure costs indicate how crucial subsurface drainage is to the Midwest U.S. farm economy, without which, excess soil water could not be removed, in turn making current levels of crop production impossible to achieve.
