Wednesday, March 11, 2015
Water Down Under: A Report from Australia by Barbara Cosens: Post 6: The Goyder Line
[The Water Down Under series of posts is by Barbara Cosens, who is in Australia this semester working on water law issues there. See more about this series, and previous posts here, here, here, here, and here.]
This weekend we drove for the first time across the “Goyder Line” into Australia’s famous outback. George Goyder was the Surveyor-General of South Australia from 1861-1893. In 1864, Goyder drew the line that bears his name to mark the northern extent of potential for development of agriculture in Southern Australia.
Like the 100th Meridian in the United States which marks the line dividing the eastern United States, in which agriculture is possible without irrigation, from the western United States where irrigation is necessary (until the coast or isolated pockets like Idaho and Washington’s Palouse).
The Goyder Line is also defined by climate – south of it the precipitation can support agriculture, north of the Line it cannot. In contrast to the north-south 100th Meridian, the Goyder Line is east-west highlighting the influence of the Southern Ocean as opposed to the Atlantic and Pacific. Also in contrast to the 100th Meridian, the Goyder Line is absolute, marking the area of agriculture and no agriculture.
As you drive north from Adelaide you leave the now famous wine regions and areas of fruit, nuts and vegetables and enter the northern wheat fields. Then all of a sudden, it ends. Scrub hills and red gum, dry drainages and large sheep stations run by pastoralists (what we would refer to as ranchers). The land is used for grazing. Red banded mountains like the Flinders Range rise from the valleys. Kangaroos and emus bed down under the gum trees to escape midday heat. The simple difference from the western United States is that there is no water source adequate for large scale irrigation in Australia’s outback. No Missouri, Colorado, Snake, or San Joaquin. Attempts to defy the Goyder Line, including the planting of wheat in Wilpena Pound in the Flinders Range during a series of wet years in the 1800’s, failed when drought returned.
Pastoralists in this part of the outback rely on the massive aquifers of the Great Artesian Basin (GAB) to water stock. Like the Olgallala aquifer, the GAB receives limited recharge. Unlike the Olgallala, the GAB quality is marginal even for stock and is not suitable to grow crops.
“Artesian” in the GAB name means the aquifer is under pressure and a well into it will flow at the surface – similar to early wells in Pullman WA into the Grand Rhonde aquifer. Pastoralists used this feature, drilling approximately 4000 wells in the late 1800’s to early 1900’s, and leaving them to flow. This made possible the raising and driving of livestock to market. The cumulative flow of these bores has begun to impact the GAB and the famous mound springs and waterholes it supports with their rare and fragile ecosystems. In recent years the Commonwealth, in partnership with the States and Territory overlying the GAB, has implemented a bore rehabilitation program to cap and control the flow. Pastoralists now use stock tanks and run wells only when needed. The more difficult bores or those that support ecosystems thought important remain. Some recovery of GAB pressure has been measured. Life of the rehabilitation is estimated at 30-50 years and no program is yet in place for cap maintenance.
The outback of Australia is as much a lifestyle as it is an ecosystem. Many of the stations now supplement income with tourism, like Rawnsley Station where we stayed. Like our western ranch towns, the population is aging with the young headed to the coastal cities. Whether the capping programs will render the water supply for this lifestyle sustainable, whether enough children will stay to find out, remains to be seen. Crossing the Goyder Line back into wheat fields and then grapevines, it seems an iconic part of Australia would be lost if they fail.