=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 11-Jun-1991 Southport 960/056 RLR(1986) is 12.7m below BM GAR 2 1939 =========================== FOLLOWING PSMSL DOCUMENTATION ADDED 12-Jul-1993 Southport 960/056 RLR(1986) is 12.7m below BM GAR 2 1939 =========================== FOLLOWING PSMSL DOCUMENTATION ADDED 15-Feb-2012 Southport is now an Historic station. Primary benchmark remained GAR 2 21.48 1939 1962 relationship value to TGZ on the original RLR diagram was 9.613m. For Epoch 1983-2001 this value was 9.615m.