Houston, J.R. and Dean, R.G., 2016. Erosional impacts of modified inlets, beach encroachment, and beach nourishment on the east coast of Florida.
Most of the 21 inlets along the 588 km of sandy shoreline on the Florida east coast have been modified, primarily to improve navigation efficiency and safety. These modifications have usually caused significant downdrift shoreline erosion. Shoreline change data for the Florida east coast during the period from about 1869 to 1971, which was before widespread beach nourishment, are analyzed. Modified inlets during this period impacted about 25% of the shoreline and conservatively caused about 70% of the shoreline area recession and about 75–85% if counties are excluded that did not have modified inlets that caused net downdrift recession. During this same period of about 100 years, the remaining 75% of the shoreline advanced on average 46 m seaward. However, before Florida began regulating coastal construction, development often encroached on accreting shorelines, effectively masking much of the accretion. From about 1971 to 2007, a period of widespread beach nourishment, only about half of the nourishment sand was placed on eroding shorelines. About half was placed on shorelines that accreted or were stable from about 1869 to 1971 but where encroachment by development made the nourishment necessary. Over half of the recession caused by modified inlets still exists. The criteria used by the Florida Department of Environmental Protection to designate the erosional state of Florida east coast beaches was found to be problematic, since it currently designates 65% of this shoreline as eroding when only 20% eroded during the period of widespread beach nourishment from about 1971 to 2007.