Murchison River (Western Australia)

Location of the Murchison River

Murchison River mouth

Murchison River at Kalbarri after heavy rains

Murchison River through Nature's Window

Murchison River from Hawk's Nest

Murchison River

The Murchison River is the second longest river in Western Australia. It flows for about Template:Convert<ref name=landgate/> from the southern edge of the Robinson Ranges to the Indian Ocean at Kalbarri. The Murchison-Yalgar-Hope river system is the longest river system in Western Australia. It has a mean annual flow of 208Template:Nbspgigalitres, although in 2006, the peak year on record since 1967, flow was 1,806Template:Nbspgigalitres.<ref name=Emu>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name=landgate>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name=doe>Template:Cite book</ref>

Basin

The Murchison River basin covers an area of about Template:Convert in the Mid West region of Western Australia. It extends about Template:Convert inland from the Indian Ocean, onto the Yilgarn craton east of Meekatharra and north of Sandstone.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Rain generally falls in the upper basin during summer cyclones, so for much of the year the Murchison River does not flow, leaving a dry sandy river bed and intermittent permanent pools.

The eastern reaches of the basin contain large chains of salt lakes, which flow only following rainfall. The drainage lines from these lakes merge to form the Murchison River about Template:Convert north-northeast of Meekatharra. The river flows west, southwest, and west to the Indian Ocean.

Within the basin are the towns of Kalbarri and Meekatharra; the hamlets of Ajana, Binnu, Barrel Well and Murchison; and the mining ghost towns of Galena, Geraldine, Abbotts, Chesterfield, Peak Hill, Yaloginda, Reedy, Nannine, Quinns, Burnakura and Gabanintha.

Course

The Murchison River rises on the southern slopes of the Robinson Ranges, about Template:Convert north of Meekatharra in central Western Australia. From there it flows in a westerly direction for about Template:Convert to its junction with its largest tributary, the Yalgar River, then west for another Template:Convert before turning south-southwest for Template:Convert, at which point it is joined by the Roderick River, about Template:Convert east of Murchison Settlement. Another Template:Convert to the south-southwest it joins another important tributary, the Sanford River. Over the next Template:Convert it makes a number of sharp turns, taking it about Template:Convert to the west. It then flows to the southwest, flowing under the North West Coastal Highway at the Galena Bridge. Entering the Kalbarri National Park, it flows first to the northwest and then to the north, flowing through the Murchison Gorge, and passing through a number of tight bends known as the Z Bend and The Loop respectively. It eventually turns to the southwest, passing through one more dogleg before discharging into the Indian Ocean at Kalbarri, the only town on the river.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}Template:Dead link</ref>

Murchison Gorge

Murchison Gorge is a deep gorge in near pristine condition. It is popular with tourists, and there are a number of tourist lookouts. It is also of geological interest, as it exposes a section through the Tumblagooda Sandstone, a geological sequence rich in Ordovician trace fossils. The maximum age for initiating major down-cutting of the Murchison Gorge, in response to regional Quaternary tectonism, is Late Eocene (33.9–38 million years ago).<ref>Template:Cite book</ref>

Estuary

The final Template:Convert of the Murchison River, from the Murchison House ford to the mouth, are estuarine, and consist of a sequence of long sandbars and shallow pools mostly less than a metre deep. The estuary is permanently open to the sea, so is constantly affected by tides and the inflow of saline sea water. When river flow is low, the estuary accumulates sediment from the ocean, narrowing the river channel; this sediment is evacuated to the ocean during periods of high flow, but high flow also brings sediment into the estuary from upriver. Because of the high sediment load, and continual stirring by wind and river flow, the water is turbid.<ref name="Brearley 2005">Template:Cite book</ref>

The mouth of the estuary is a small delta, closed by a sandbar except for a narrow channel. Although this channel is permanently open, it is usually very narrow and shallow, and so is now dredged every year to allow passage by western rock lobster fishing boats.<ref name="Brearley 2005"/>

History

The Murchison River was named by the explorer George Grey, whose boats were wrecked at its mouth on 1Template:NbspApril 1839, during his second disastrous exploratory expedition; the name honours Grey's patron, the Scottish geologist Sir Roderick Murchison.<ref name=grey>Template:Cite book</ref> Murchison's advocacy had been essential in securing official support for Grey's Western Australian expeditions.<ref>Template:Cite book</ref>

Murchison House Station, one of the oldest stations in Western Australia, was established by Charles Von Bibra on the banks of the river toward the western end in 1858.<ref name=mhs>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

The estuary and river mouth was used as a holiday destination by families from the Galena mines in the 1920s and 1930s, and a military holiday camp was built there during World WarTemplate:NbspII.

In 1951 the town of Kalbarri was gazetted at the river mouth, and by the end of the 1990s the population was about 2,000. In 1963 the Kalbarri National Park was gazetted, formally protecting the lower reaches of the river, including the gorge.<ref name="Brearley 2005"/>

The Galena Bridge, carrying North West Coastal Highway over the river at Galena, was opened by the Main Roads Department in December 1983.<ref>Edmonds, Leigh (1997), The vital link : a history of Main Roads Western Australia 1926-1996 Nedlands, W.A. : University of Western Australia Press. Template:ISBN. page 452</ref>

Flooding

Flooding occurred in 1866 resulting in the Geraldine Mine being drowned;<ref>Template:Cite news</ref> more flooding occurred in 1882.<ref>Template:Cite news </ref>

The southern branch flooded out to a distance of Template:Convert from the river bank in 1884 and the main homestead at Moorarie Station was washed away with about 3,000 ewes and lambs.<ref>Template:Cite news</ref>

The river was once again flooded in 1900 following heavy rains with the river estimated to be running Template:Convert wide, road to Cue and Peak Hill were submerged under Template:Convert of water. Roads were cut for up to a fortnight resulting in food shortages in many isolated towns.<ref>Template:Cite news</ref> Ernest Lee Steere of Belele Station reported that over Template:Convert of rain fell in less than a fortnight. Further downstream the river was reported to be running Template:Convert wide and at depths of up to Template:Convert; despite the damage, pastoralists were jubilant at how quickly the grasses were growing.<ref>Template:Cite news</ref>

Heavy flooding occurred along the course of the river in March 1926 following heavy rains upstream.<ref>Template:Cite news</ref> 15 to 20 men were stranded at the Three Sisters Mine on the north side of the river, at Galena, and were rescued by dinghy.<ref>Template:Cite news</ref>

Flooding again occurred in 1939<ref>Template:Cite news</ref> and 1942,<ref>Template:Cite news</ref> and once more following another significant rain event in February 1945 that resulted in flooding and the old Galena Bridge being swept away, effectively stranding the citizens of Carnarvon. A ferry service was established using a fishing boat.<ref>Template:Cite news</ref> Bananas were the main item that urgently needed to be sent across for transport to market.<ref>Template:Cite news</ref>

Following Cyclone Emma in 2006, much of the catchment area received Template:Convert of rainfall. The river swelled, reaching a width of over Template:Convert in places, and Kalbarri had to be sandbagged to protect it from floodwaters.<ref>Template:Cite news</ref>

See also

• Bilyuin Pool
• Pencell Pool
• Wooleen Station

Further reading

• Curry, P.J. et al. (1994) An inventory and condition survey of the Murchison River catchment and surrounds, Western Australia. Department of Agriculture, Western Australia: Technical Bulletin Number 84. Template:ISBN
• Western Australia. Dept. of Land Administration. Cartographic Services Branch.(1991) Land systems of the Murchison River catchment and surrounds : map series to accompany W.A. Department of Agriculture technical bulletin no. 84 Map Data: Scale 1:250,000 (E 115° 10′--E 118° 45′/S 25°—S 28° 10′).Notes: Land systems of the Murchison River catchment and surrounds by K.A. Leighton ... [et al.]. Date of survey: 1986-1988. Location maps:Belele, Byro, Cue, Glenburgh, Murgoo, Robinson Range.