I read in the book "Calumet Beginnings" (written by a close friend of my mother) about the early history of northern Indiana according to this book the Grand Calumet River in Indiana a portion of it was dug out where the Pottawatomie Indians where they would portage their boats to Lake Michigan
Does building pyramids count? The city of Cahokia was built in what is now Illinois. It was a massive metropolis complete with massive earthen step pyramids built for various purposes.
It is now a National Historical Site.
Ortona earthworks complex in Florida. Trading routes between various locations, also some possible defensive uses. Lots of work by UF folks in anthropology and archeology fields. For example http://ufdc.ufl.edu/UF00027829/00041/2j
There are a number of large dams in Mexico such as the presa purron in Puebla or the dam at Teopantecuanitlan. The site of Kaminaljuyu also contained extensive water management structures.