Brisbane River

Captain Cook Bridge from Kangaroo Point Lookout

The Brisbane River is situated in southeast Queensland, Australia, and flows through the state capital Brisbane, before emptying into Moreton Bay. The river is dammed by the Wivenhoe Dam, forming Lake Wivenhoe, the main water supply for Brisbane. The river was named after the Governor of New South Wales Sir Thomas Brisbane by the explorer John Oxley in 1823.

The CityCat ferry service collects and delivers passengers along the inner-city reaches of the river. The Port of Brisbane manages the movement of larger vessels into the river from the bay.

History

Goodwill Bridge and CityCat from Victoria Bridge.

There is no written Aboriginal history of the river prior to settlement by Europeans. Four European navigators, namely Captain Cook, Matthew Flinders, John Bingle and William Edwardson, all visited Moreton Bay but they failed to discover the river. Three castaways who were caught in a gale and blown off course all the way from Sydney to Moreton Island were found by Oxley while he was surveying the east coast for a new penal settlement. They had previously wandered the area, walking along the river up to Oxley Creek.

On the 2 December 1823, Oxley and his crew, including two of the castaways, Pamphlett and Parsons, entered the river and sailed upstream as far as present-day Goodna. Oxley noted the abundant fish and tall pine trees. Early european explorers marvelled at the sheer natural beauty they witnessed while travelling up the lower reaches. Also during 1823, the river was named after Sir Thomas Brisbane, the then Governor of New South Wales.

Upon the establishment of a local settlement in 1824, other explorers such as Allan Cunningham, Patrick Logan and Major Lockyer made expeditions and surveys further upstream, and, in 1825, the Moreton Bay penal colony at Redcliffe relocated to North Quay.

From 1862 the Brisbane River has been dredged for navigation purposes. Throughout much of the 20th century large quantities of sand and gravel were extracted from the estuary of the river. Since the rate of materials being deposited is not as high as that which was removed, the river has acted as a subaqueous mine.

There was also much dredging and widening work done over the years to allow ships to transport cargo to and from Brisbane. The river has served as an important carriageway between Brisbane and Ipswich before a railway linking the towns was built in 1875. By early 1825 bouys were being laid along the South Passage and shortly after that the first pilots were commissioned to guide ships entering from Moreton Bay and another service for those travelling upstream.

The first small private wharves were built on the river in about 1848. In 1866 there was a breakwater built at the junction of the Bremer and Brisbane rivers that was designed to stop shingle from blocking the access to the Bremer's boat channel. The first pile light using kerosene was built in 1882. The steel framed light also served as an early port signal station.

The river depth was progressively increased and narrow points widened to allow larger vessels into the river and further upstream. For navigation and safety reasons the Seventeen Mile Rocks were completely removed in 1965. The northern river bank at the mouth of the river has undergone reclamation projects over the years, especially in the suburbs of Hamilton and Pinkenba. More recently, extensive port facilities have been constructed on Fisherman's Island which has also seen significant land reclamation into the bay.

Early rivers crossings were made by rowing ferries followed by steam ferries. In 1865 the first Victoria Bridge, later destroyed in a flood, was built across the river.

Bridges

Main article: Bridges of Brisbane

Currently the Brisbane River is crossed by 12 major bridges, including the historic Story Bridge and tolled Gateway Bridge.

Tributaries

Brisbane River as viewed from the Brisbane City Botanic Gardens.

The following major tributaries flow into the Brisbane River:

• Bulimba Creek
• Breakfast Creek
• Norman Creek
• Oxley Creek
• Cubberla Creek
• Moggill Creek
• Bremer River
• Lockyer Creek
• Stanley River

The following smaller creeks also flow into the river; Wolston Creek, Woogaroo Creek, Goodna Creek, Six Mile Creek, Bundamba Creek, Pullen Pullen Creek and Kholo Creek.

Floods

The Brisbane River floods frequently, although the occurrence and magnitude of flooding has diminished following the construction of the Wivenhoe Dam on the upper reaches of the River.

Past floods have resulted in both deepening and reduction in river depth, creation of new sand banks and shoals as well as increased transport of suspended sediment from upstream. Before the invention of modern dredging techniques the sediment deposited by flooding created hazards to ships navigating the river. Even medium sized vessels no longer travel up the Brisbane River beyond the city reach, and dredging of the upper reaches has ceased, allowing the river to recover substantially from the fine silt dislodged by gravel and sand extraction.

Significant floods have occurred several times since the European settlement of Brisbane. Notable instances of flooding include:

• 14 January 1841 (Highest flood level to date)

• February 1893, a sequence of flood peaks over some three weeks saw the highest recorded flood level in the Brisbane central business district. Seven lives were lost in the Eclipse Colliery at North Ipswich as a direct result of the flooding. Several other lives were lost to drownings.

• 27 January 1974 (Largest flood to affect Brisbane City in the 20th Century).

The most significant of these events was the 1974 Brisbane Flood.

Flooding along the Brisbane River has the potential to be devastating. For much of the river's length its banks are relatively high, but topped by a broad plain. The river's sinuous course means that flood waters from upstream cannot be quickly discharged into Moreton Bay. Thus higher than normal flows cause river levels to rise rapidly and once the top of the banks are breached the floodwaters can spread over wide areas of the city.

Environmental concerns

Environmentally, the river is in a poor condition and has been so for many years. The major causes of pollution are excess nutrients, hydrocarbons, pesticides and bacteria which become concentrated in the river and its sediment after flowing off surrounding lands. This river is also considered too murky and it is not recommended to swim in its waters.

Historically, the river was actively dredged by Boral Sands Inc, ostensibly to make the river navigable. The constant extraction of river bed material by dredges has had considerable effect on the river. These impacts include increased turbidity, bed and bank erosion and changes in tidal hydraulics. The tidal nature of the river and the generally muddy nature of the sands removed by dredging created a woefully sludgy clayey sediment load in the river which did not clear. The efficacy of dredging the river upstream of the city reach to make it "navigable" was always in doubt, and the effect of the artificial sediment load in Moreton Bay grew to concern environmentalists worried that sediment was choking sea grass paddocks which were grazing territory for dugong. In a meeting concerning the matter in October 1996, including two State Government Ministers and three Mayors, an agreement to cease the dredging of sand and gravel from the river by September 30, 1997 was formed. Boral Resources Pty. Ltd. resisted the agreement, but ultimately all dredging was stopped by the agreed date.

The river has several important ecological areas where remnant populations of mangroves exist; these include areas around drainage culverts, in Breakfast Creek, New Farm, a small preserve at the city bend, near the Queensland University of Technology and around the shipping terminals at the river's terminus into Moreton Bay.

These mangroves have recently become classified as protected nature reserves.

Kangaroo Point Cliffs

On the southern side of the river, opposite Gardens Point, are the Kangaroo Point Cliffs. The Kangaroo Point Cliffs are not natural. They were created by a quarrying operation which mined the volcanic rock or rhyolite lava flows which form the cliffs. These lavas were deposited in the Tertiary period about 30 million years ago and filled up an ancient river valley. They currently form the banks of the Brisbane River.

Brisbane River Cod

The freshwater reaches of the Brisbane River once supported a unique species of cod, similar to Murray cod and closely related to eastern freshwater cod. Unfortunately this unique native fish became extinct somewhere between the 1930's and 1950's due to habitat degradation and overfishing.

References

• Craig Johnstone. (July 22, 1995). "How we're slowly killing our river". The Courier-Mail - Weekend p. 1
• G Roderick McLeod. 1990. "Some aspects of the History of the Brisbane River". In Peter Davie, Errol Stock, Darryl Low Choy (Ed.), The Brisbane river: a source-book for the future. pp. 191 - 201. Australian Littoral Society in association with the Queensland Museum.
• Wayne Erskine. 1990. "Environmental Impacts of sand and gravel extraction on river systems". In Peter Davie, Errol Stock, Darryl Low Choy (Ed.), The Brisbane river: a source-book for the future. pp. 295 - 302. Australian Littoral Society in association with the Queensland Museum.

External links

• Historical Brisbane River Map - includes photos and information about Brisbane, the Brisbane River, Brisbane bridges and Brisbane suburbs
• History of Brisbane flooding at BOM