Depth of closure is studied on a nourished beach in the light of its autonomous behaviour over long temporal and large spatial scales. Long term data show that depth of closure is variable alongshore, being shallower to the west and deeper to the east. Following placement of a shore nourishment along the middle section of the coast, the spatial variation of depth of closure changes. Initially the depth of closure is shallowest where the fill was placed. With time after the placement of the fill, this effect diminishes. Depth of closure observed in this study is influenced by bar behaviour. The fill material affects the observed depths of closure by reducing offshore bar migration. Maximum depths of closure for any particular timescale observed in this study are well predicted by the Hallermeier (1981) formulation for the depth limit to the active profile. In conclusion, pre-fill observations and Hallermeier (1981) provide a useful limit to the observed post-fill depth of closure. Similar analysis of other beach nourishment projects would be useful.