S.C. Code § 49-17-1110
Whenever it may be desirable to construct, widen, deepen, straighten or change any ditch, drain, watercourse or levee lying on, along, across or near the State line between this State and any adjoining state or whenever it may be desirable to construct, repair or improve any work of drainage as provided for in this chapter which cannot be constructed, repaired or improved in the best manner without affecting land in any such adjoining state the board of drainage commissioners in the county in which such work is located may join with the proper officers of such adjacent counties of any other state in the construction, widening, deepening, straightening, repairing or improving of any such drain, ditch, watercourse or other work of drainage.
S.C. Code § 49-17-1110