However, as a practical matter, EPA anticipates that the management measure set forth above generally will be implemented by applying one or more management practices appropriate to the source, location, and climate. The practices set forth below have been found by EPA to be representative of the types of practices that can be applied successfully to achieve the management measure discussed above. Generally, SMAs should have a minimum width of 35 to 50 feet. SMA width should also increase according to site-specific factors. The primary factors that determine the extension of SMA width are slope, class of watercourse, depth to water table, soil type, type of vegetation, and intensity of management.
Many States use SMAs.
Examples of SMA designation strategies from Florida, North Carolina, Maine, and Washington are presented. Florida's SMZs are divided into a fixed-width primary zone and a variable secondary zone, each of which has its own special management criteria. Table 3-18 presents North Carolina's recommendations for SMZ widths for various types of waterbodies dependent on adjacent upland slope. Minimize disturbances that would expose the mineral soil of the SMA forest floor. Restrict mechanical site preparation in the SMA, and encourage natural revegetation, seeding, and handplanting.