From the historic shoreline maps, the amount of erosion and accretion (land gained) can be determined. Shoreline changes from 1852-1942 reflect natural processes. During this period, up to 1500 ft of shoreline was eroded at NE Follets Island. At Surfside, the shoreline prograded seaward by 1000 ft, because it was supplied with Brazos sediments prior to 1929, when the lower Brazos was diverted.

A net  of 1.7 sq. mi. of land were lost to the sea from 1852-1942.