[colechristensen]

Pipes as little as 30 to a few hundred feet apart. There are parts of the state where they're literally everywhere.

Here's some drainage basics:

https://fyi.extension.wisc.edu/drainage/files/2015/09/Basic_...

There is extensive law regarding drainage and interconnection obligations between landowners, Iowa is pretty flat, there just has to be a path between your fields and a local river. All of the roads are edged with drainage ditches, there are bigger much deeper ditches where necessary to direct water.

http://publications.iowa.gov/19966/1/IADOT_tr_497_Iowa_Drain...