Iowa Code § 6A.13: Change in streams.

When a railway company would have the right to excavate a channel or ditch and thereby change and straighten the course of a stream or watercourse, which is too frequently crossed by such railway, and thereby protect the right-of-way and roadbed, or promote safety and convenience in the operation of the railway, it may, by condemnation or otherwise, acquire sufficient land on which to excavate such ditch or channel.