US Army Corps of Engineers

The US Army Corps of Engineers regulates water quality, channel conditions and provides 404 permitting 

Federal Emergency Management Agency (FEMA)

FEMA provides oversight on levees and flood control issues

Arizona Department of Water Resouces (ADWR)

ADWR concerns itself with dam safety

Flood Control District of Maricopa County (FCDMC)

FCDMC provides assistance with flood control issues and levee maintenance