 The USACE began work on ecosystem restoration projects along the lower Missouri River in the early 21st century . Because of the low use of the shipping channel in the lower Missouri maintained by the USACE , it is now considered feasible to remove some of the levees , <unk> , and wing dams that <unk> the river 's flow , thus allowing it to naturally restore its banks . By 2001 , there were 87 @,@ 000 acres ( 350 km2 ) of riverside floodplain undergoing active restoration . 
