=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 06-Jul-1993 Cambridge II RLR(1974) is 8.0m below BM 1 =========================== FOLLOWING PSMSL DOCUMENTATION ADDED 20-Dec-2011 Using NOAA data the RLR diagram has been revised. Previous Primary benchmark BM 12.012m above gauge datum no longer appears in the NOAA reports. Primary benchmark is now 1892 D 1980 3.344m above gauge datum.