The U.S. Army Corps of Engineers (USACE) exercises regulatory authority under Section 10 of the Rivers and Harbors Act of 1899 (33 USC 403) and Section 404 of the Clean Water Act, 1972 (33 USC 1344) for certain activities in "waters of the United States (U.S.).”
A permit is required for activities that would include the discharge of dredged and/or fill material below the Ordinary High Water elevation of any "waters of the United States (U.S.)" or any wetlands pursuant to Section 404 of the Clean Water Act. "Waters of the U.S." include all waters which are currently used, were used in the past, or may be susceptible to use in interstate or foreign commerce as well as hydrologically connected lakes, rivers, and stream channels exhibiting an Ordinary High Water Mark (OHWM); wetlands; sloughs; and wet meadows and wetlands adjacent to “waters of the U.S.”
A permit is also required for any work performed in or in the immediate vicinity of a Section 10 Navigable Water pursuant to Section 10 of the Rivers and Harbors Act of 1899 in consideration of potential impacts to navigation. A complete list of Section 10 waters can be found below.
Activities not requiring permits can be found here (40 CFR 232.3):
One step Removal Guidance
One step removal requires that the sediment and debris must be removed and immediately placed landward sufficiently enough to prevent the runoff water from the dredged material from re-entering the stream and that no additional dredged and/or fill material is placed below the ordinary high water mark of the stream or in wetlands. We recommend, however, that good management and conservation practices be used. For example:
a. The dredged (excavated) material should be placed sufficiently landward in a contained manner and immediately stabilized by spreading and seeding;
b. Straw or hay bale barriers or other approved berming methods for controlling and containing sediment should be used if the dredged material is discharged within close proximity to any "waters of the United States;"
c. The removal of vegetation should be limited to the removal of snags, loose debris and live vegetation which obviously obstructs stream flow;
d. All work, including the removal of vegetation, should be performed from one side of the channel leaving one side undisturbed; and
e. The side casting of dredged material into wetlands adjacent to the stream is not allowed under one step removal and would require authorization before the work is done.