© 2003 Eugene S. Takle
The landscape of north central Iowa before the European settlement of the
mid to late 1800s consisted on prairie pot holes with seasonal standing
water. Iowa has almost 12,000,000 acres (4,500,000 hectares) of poorly
drained soil. This soil provides rich and productive farm land and has
been drained by the use of agricultural drainage tile installed at 100 ft
intervals across fields. Therefore, approximately 1 million miles of
drainage tile underlies Iowa's poorly drained soils. By adding to this
the length of tile underlying soils that are marginally drained, I
estimate that there are about 1.3 million miles of drainage tile in the
state. Northern Illinois has similar poor drainage, as do parts of
Indiana, Ohio, southern Minnesota, and northern Missouri. Adding
contributions from these states, we likely have over 3 million miles of
drainage tile underlying the Midwest. Laid end to end, this tile would
stretch from the Earth to the Moon and back 6 times. This massive tile
system eliminates, or reduces the time period for, standing water on the
surface over large regions, which, in turn leads to less surface
evaporation and higher daytime surface temperatures. It might be argued
that this hydrological change to the landscape rivals the Three Gorges Dam
in China for the scale of impact.
For more information refer to:
http://ohioline.osu.edu/aex-fact/0320.html