floods

Brisbane flood map, 1974. Based on field inspection, aerial photographs as well as information made available from the Brisbane City Council, this map was prepared by the Survey Office and published in February 1974.  The extent of the Australia Day floods is shown as a red line, while according to various heights at the Port Office gauge, ‘areas of probable inundation’ were shaded blue, pink, yellow, green and plum. This information was obtained from an earlier flood map produced by the Bureau of Industry in 1933. The location of the massive tanker, the ‘Robert Miller’, is shown downstream of Kangaroo Point where it broke its moorings during the flood. According to the Survey Office, while the map was compiled from ‘the best information available’, it contained a clear warning for users: ‘no warranty is given to the correctness of the flood perimeter shown hereon.’ Lack of reliable contour information in 1933 as well as physical changes to the flood plain and channel since would all affect the possible extent of a flood. This was demonstrated in 1974 when Brisbane River invaded further than expected while other areas remained dry. A copy of this map could be purchased for $1. Collection of the Museum of Lands, Mapping and Surveying

Township and works at Somerset Dam, 1937. For the purposes of building Somerset Dam, a small township was established at the construction site.  As shown by this map, the township boasted a hospital, school, police station and even tennis courts. A ‘swimming pool’ was located downstream in the river. The workshops, storage sheds and crushing plant were located upstream. The stone quarry, used for dam building, was at the top of the hill. By 1937, 126 workers’ cottages were constructed. The inset in the top left corner shows the location of the dam above the junction of the Stanley and Brisbane Rivers. In a letter to the Brisbane Courier in 1935, H.P. Somerset explained that his name’s association with the dam and township was not in relation to his efforts to warn Brisbane back in 1893, rather, it was his suggestion of the site after writing to the Water Board in 1906. Somerset was flatteringly described as an ‘engineer’ for noticing the rock formation as well as its suitability for dam construction. Queensland Parliamentary Papers, Vol.2, 1937

Proposed flood diversion canal scheme, 1896. Under J.B. Henderson’s direction, the Water Supply Department investigated a variety of flood mitigation schemes to protect Brisbane from future floods. A report was presented to Parliament in 1896 and included this map of two flood diversion canals. According to Henderson, at the time there appeared to be a ‘prevailing belief  ̶  that without difficulty a canal could be formed at some point on the river to the sea by means of which floods below the canal entrance at the river end would be wholly averted.’ However, building them would not be simple. Either canal would involve the purchase of much land, the construction of several new bridges, revetting to protect embankments, and finally an inlet weir. According to Henderson’s calculations, the excavation alone would cost £9,523,194 for the upper Oxley canal, shown in orange, and about £7,138,000 for the lower Yeronga canal shown in light blue. In addition to affecting navigability and tidal behaviour of the Brisbane River, the canals would need frequent dredging. Henderson advised parliament to abandon consideration of this and other similar schemes. Queensland votes and proceedings, vol.4, 1896

Channel widening and river training scheme, 1896. Under the direction J.B Henderson, this channel widening and river training scheme was proposed by the Water Supply Department in 1896. To prevent a repeat of the disastrous 1893 floods, areas shaded orange would be removed to widen the channel. A series of flood walls would also be built to protect the inner city and South Brisbane. Where the walls would abut existing permanent structures, watertight joints would be formed keeping flood waters in the channel. These walls would have gates at key locations only closed in the event of a flood higher than in 1890. In the city, flood gates were proposed on the corner of Creek and Charlotte streets and on the corner of Alice and Edward Streets. In South Brisbane, flood gates were proposed at the end of Russell, Glenelg, Ernest and Tribune streets. This map includes the 1893 flood line and shows only part of the Victoria Bridge which was destroyed during the flood. Queensland votes and proceedings, vol.4, 1896