S.C. Code Ann. § 54-3-620

No person shall build or extend any wharf or other obstruction in or upon the waters of the bay or harbor of Charleston or the rivers or creeks flowing therein without first obtaining, in writing, from the Authority a permit for so doing, except when the lines of such wharf have been fixed by any grant or by authority of State legislation, under a penalty of twenty dollars for every day such wharf or obstruction shall remain.