Brisbane flood heights, 1841-96

Brisbane flood heights, 1841-96. In response to the 1893 floods, the head of the Water Supply Department, J.B. Henderson, compiled this diagram in recording the history of floods from 1841. Based on historical accounts, it was probably the first time any comprehensive and comparative analysis had been made. According to reputable accounts, Brisbane’s first recorded flood was in September 1825, but no information could be found regarding its height and it was not included. The first major flood shown on this diagram was 14 January 1841 which, by Henderson’s calculations, was at least two inches higher than the ‘Great Flood’ in early February 1893. Included on the diagram were the computed flood levels for three flood mitigation schemes recommended by the Water Supply Department: ‘A’, ‘B’, ‘C’. Scheme ‘B’, straightening the river by cutting through Kangaroo Point and New Farm, would have the highest flood mitigation impact. According to Henderson, in an 1893 flood event the water level would be reduced to about one foot over the floor of the Queen’s Hotel, the equivalent height above the Norman Wharf. Queensland votes and proceedings, vol.4, 1896