Why are some regions of the U.S., such as Ohio, unlikely to run short of water while others are very likely to run out of water?

Question

What will be an ideal response?

Answer 1

It all depends on the mean rainfall in the region. Roughly east of the Mississippi
River, there is more rainfall than needed for normal (unirrigated) agriculture. This is also
generally true along the Pacific coast, though more so the farther north one goes and less so
the farther south.
The region from west of the Mississippi River to the Pacific Cordillera normally has lower
rainfall than is needed for normal agriculture. In the nineteenth century, rainfall was above
the longterm average, and settlement was possible. People believed that "rainfall follows the
plow." However, the region's rainfall levels returned to average in the twentieth century, and
irrigation grew apace in this region of the country. The "buffalo commons" idea suggests
returning the land to bison in this region and having human habitation thinned out as
farming is phased out.