Beachfront Jurisdictional Lines webpage (general information, Beachfront Management Reform Act (Act173) summary):
https://scdhec.gov/environment/your-water-coast/ocean-coastal-management-ocrm/beach-management/state-beachfront

Beachfront Jurisdictional Lines Stakeholder Workgroup webpage
https://scdhec.gov/environment/your-water-coast/ocean-coastal-management-ocrm/beach-management/beachfront-jurisdictional

YouTube video of the Beachfront Jurisdictional Lines Process (covers alot of the information I presented):
https://youtu.be/F3w8ZdPSDAo

Jurisdictional Lines web application (for survey packets, line reports):
https://gis.dhec.sc.gov/shoreline/

BERM Explorer (beach profiles): 
https://gis.dhec.sc.gov/bermexplorer/

Beach Renourishment web application:
https://gis.dhec.sc.gov/renourishment/

The regulatory guidance for the construction of dune walkovers is located in the S.C. Code Ann. Regs. 30-13(0)(1):
https://www.scstatehouse.gov/coderegs/Chapter%2030.pdf