How do I determine the back of the shoreline?

The back of the shoreline is defined by the MDMAP as the first major change in substrate, which may include a vegetation line, cliff, or other barrier. If you are interested in also monitoring debris that may be pushed back into vegetation behind the beach during storms, that debris should be tallied on a separate data sheet so that it's not included in the calculated debris flux or concentration. Data entered into the NOAA database should only reflect the debris up to the first change in substrate. If the back of the shoreline is only a partial barrier, for example a patch of vegetation behind which there is more beach, then survey up to the first continuous barrier (include that vegetation patch and the area behind it). In some cases, shoreline sites may be too complex to clearly delineate a maximum landward limit where debris might be deposited. These types of sites, and shorelines that are very high energy or dominated by sedimentary deposits, may not be good shoreline survey candidates. For the same reason, barrier islands and other shifting substrates are not ideal survey locations.