(a) The procedures of this part, in addition to the provisions of 33 CFR parts 335 through 337, should be followed when undertaking Corps operations and maintenance activities involving the discharge of fill material into waters of the U.S., except that the procedures of part 336 of this chapter will be used in those cases where the discharge of fill material is also the discharge of dredged material, i.e., beach nourishment, within banks disposal for erosion control, etc.(b) After construction of Corps Civil Works water resource projects, certain operations and maintenance activities involving the discharge of fill material require evaluation under the CWA. These activities generally include lakeshore management, installation of boat ramps, erosion protection along the banks of navigation channels, jetty maintenance, remedial erosion control, etc. While these activities are normally addressed in the existing environmental impact statement for the project, new technology or unexpected events such as storms or high waters may require maintenance or remedial work not fully addressed in existing environmental documents or state permits. In determining compliance with the applicable environmental laws and regulations the district engineer should use the CWA exemptions at 404(f) and NEPA categorical exclusions to the maximum extent practicable. If the district engineer decides that the changes have not been adequately addressed in existing environmental documentation, the procedures of this part should be followed.53 FR 14920, Apr. 26, 1988