Four islands in Lake Lanier are getting help to defend against waves and boat wakes that have eroded their shorelines since the lake was built in the 1950s. Lake Lanier Association has teamed up with Hall and Gwinnett counties, private businesses and the Army Corps of Engineers to put heavy stones, or riprap, along the shores of the islands — basically hilltops before the area was flooded to create the lake. In all, some 6,500 tons of stone will be used to line 3,150 feet of shoreline on Browns Bridge, Aqualand, Six Mile and Van Pugh islands south of Browns Bridge, which spans Lanier at the Hall and Forsyth county lines.