Lake Eyre

A few studies have found potential surfaces with a stable minimum at the transition point, with two very small barriers then going toward the reactants and products. This phenomenon is referred to as Lake Eyring Henry Eyring, one of the inventors of transition state theory, suggested that such a situation, analogous to a lake in a mountain cleft, could occur. In a study by Schlegel and coworkers, it was determined that this energy minimum can occur as an artifact of the MP2 wave function. This was found to be a mathematical quirk of the MP2 wave function, and to a lesser extent MP3, that does not correspond to reality. The same effect was not observed for MP4 or any other levels of theory. 

Fig. 1. Potential energy surface and classical trajectory calculations on the H + H2 hydrogen exchange reaction. Note the orbiting trajectory in the vicinity of Lake Eyring . Despite the unrealistic nature of a well near the transition state of this reaction, many of the modern ideas of chemical reaction theory can be seen in action already in this work. (See Ref. 1.)...

The Lake Eyre Basin in Australia contains the world s largest ephemeral lake. During the Quaternary the climate fluctuated between relatively arid and... 

The concentration of elements that are derived from rock weathering (Ca " ", Mg " ", Na" ", K" "), are less variable than runoff even in the driest conditions. The opposite is observed for CP and 804 , which are characterized by very low Qi quantiles. The retention of sihca, particularly under the driest conditions, makes its yield the most variable. The lowest yearly average runoff in this data set (3.1 mm yr for Q ) actually corresponds to the conventional limit for occasional river flow (3mmyr ). Under such extremely arid conditions, flow may occur only few times per hundred years, as for some tributaries of Lake Eyre in Central Australia. The other mnoff quantile Qgg corresponds to the wettest regions of the planet bordering the coastal zone. 

Bass-Becking L. G. M. and Kaplan I. R. (1956) The microbiological origin of the sulfur nodules of Lake Eyre. Trans. Roy. Soc. Austral. 79, 52-65. 

Alexandre, A., Meunier, J.-D., Llorens, E., Hill, S.M. Savin, S.M. (2004) Methodological improvements for investigating silcrete formation petrography, FT-IR and oxygen isotope ratio of silcrete quartz cement, Lake Eyre Basin, Australia. Chemical Geology 211, 261-274. 

Alley, N.F. (1998) Cainozoic stratigraphy, palaeoenvironments and geological evolution of the Lake Eyre Basin. Palaeogeography, Palaeoclimatology, Palaeoecology 144, 239-263. 

A full range of sedimentary environments equivalent to the more commonly described clastic deposits is also occupied by evaporite facies where climate and hydrology permit. Indeed, small changes in these parameters commonly lead to fresher water clastic and carbonate sediments interbedded with evaporites, such as in Great Salt Lake, Utah (Spencer et al., 1985). In other cases (e.g. Lake Eyre) irregular flood cycles are recorded as multiple silt-mud-gypsum triplets, because clastic bedload material is first deposited followed by evaporation of the lake water and precipitation of the dissolved load. 

Praia, A.J. (1990) Satellite-derived evaporation from Lake Eyre, South Australia. International Journal of Remote Sensing 11, 2051-2068. 

Southern Cross, Western Australia. (B) Lake Eyre North, Australia, after partial flooding and evaporative retreat. (C) Western shoreline of Lake Frome, South Australia. (D) Halite crust, Lake Frome, South Australia. (E) Halite crust with sinuous salt-crystallisation pressure ridges, Sickle Lake, Northern Territory, Australia. (F) Pervasive mudcracked texture, Dry Mudflat facies, Lake Eyre North, Australia. (G) Regressive strandlines, Lake Buchanan, Queensland, Australia. (H) Regressive shorelines, Lake Buchanan, Queensland, Australia. 

Australia, as the driest continent and partly because it is also the flattest, has different water supply problems. Long periods of drought prevail for 20 years or more over much of the interior, punctuated by brief periods of flooding. These factors contribute to the coastal location of all major Australian cities. Lake Eyre, a great salt lake of 9,300 square km, which occupies a shallow basin in the interior, a part of which lies 15 m below sea level, is usually dry. It completely fills only about twice a century, and completely dries up again within about 2 years. 

Lake Eyre 330 Diamantina River / Indian Ocean [Pg.295]

MUSYL M K and keenan c p (1992) Popnlation genetics and zoogeography of Austraiian freshwater golden perch, Macquaria ambigua (Richardson 1845) (Teieostei Percichthyidae), and electrophoretic identification of a new species from the Lake Eyre hasm, Australian Journal of Marine and Freshwater Research, 43,1585-1601. 

Geo-Engineering South Australia The Case of Lake Eyre... 

Fig. 89.1 Port Augusta to Lake Eyre Pipeline Corridor. A slightly different course might prove better if only the South Basin is to be filled at the Lake Eyre terminal south of the proposed Goyder Channel Tension Textile Dam. (Source Feieidoun Ghassemi Ian White, 2006, Fig. 7.5, p. 146)...

Bringing seawater to Lake Eyre has been discussed since at least 1883 but here, for the first time ever, we offer technical and economical details. The macroproject will utilize 0.11% of Australia s territory that is below present-day global sea level, most of which is entirely unsettled and has a small annual GDP economic impact, even though it is also often described as picturesque (Gibbs, 2006). This study does not provide final macroproject solutions there are additional problems that must be investigated before any political and financial decision-making. Some of these problems are enumerated in the section entitled Ecological, Cultural and Social Consequences. 

The macro-project assumes Lake Eyre is permanently filled with seawater. When Lake Eyre is full, and its ASL is h-5 m (16.4 ft), Lake Eyre covers an area of 19,600 km (7,509 mi ) and contains 215 km of saline liquid. It might be best to envision Lake Eyre with an artificial level of -3.5 m (11.48 ft) ASL, an area of 9,920 km (3,800 mi ) and a volume of 75 km (Eig. 89.2). Even a lower filling level such as -6 m ASL, 55 km, constitutes an ambitious macro-project aim. Such a vision offers a Lake Eyre where both the North and South basins are filled constantly and joined through the Goyder channel. The water volume and the surface area of a full Lake Eyre is denoted Fiake and Siake, respectively. Here we accept Flake = 75 km and Siake = 9,920 km. ... 

The source of incoming water into the lake may be non-continuous (massif rains, occurring at a random time interval t). Lake Eyre South is known to have filled in 1938,1955,1963,1968,1973,1974,1975,1976 and 1984. In 1984 Lake Eyre South overflowed to Lake Eyre North. In 1974 water flowed from Lake Eyre North to Lake Eyre South between March and October when an equilibrium level was obtained. Groyder Channel is a 15 km (9.3 mi)-long topographic depression that links Lake Eyre North and South (see Fig. 89.1). The width as well as lowest elevation of the... 

Long term flooding of Lake Eyre may have important consequences for the sparse human population nearby. In terms of aims, this macroproject proposes the ESR as a center of a region of biosaline agriculture. Other possible benefits are briefly enumerated in the section entitled Seawater Irrigation Macroproject. 

The source of seawater for Lake Eyre may be a continuous or non-continuous macro-engineered addition from the Indian Ocean. Lake Eyre s South basin lies 356 km (221 mi) from Port Augusta. Cost-free seawater can be extracted from Spencer Gulf. The duct length and diameter is denoted Lduct and T>duct, respectively, while its maximum elevation above sea level is //duct-... 

Table 89.1 Ptirameters for Port Augusta to Lake Eyre Pipeline...

Earlier estimates show that the annual rainfall on Lake Eyre amounts to " 125 mm (4.92 in) with an average annual pan-evaporation of 3,800 mm (149.6 in). The difference between these two quantities gives the net specific evaporation rate. The measure of evaporation used in a recent report (McMahon et al., 2005) is the mean annual area potential evapotranspiration (APET). APET values vary from 1,000 mm/year in the south of the Lake Eyre Basin to >1,500 mm/year in the north (Fig. 89.5 for monthly evaporation rates). For an average value of 1,250 mm/year, one finds g(evap,i) = 0.396 10 m /m /s. 

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