The Victorian naturalist . rther blocked by analluvial fan of granitic sand (Thomas,1937). The lake is 770 ha in area with acircumference of almost 15 km and isorientated with its major axis in aSW-NE direction. The floor is flat, butis slightly lower at the SW end. In-terestingly Bennett and Schwerdtfeger(1970) reported a lowering of thewater table towards the NW end, sug-gesting the possibihty of a leak thereassociated with faulting. However,the shape of the lake (Fig. 1) andbottom topography tend to deny suchan origin, but there has probably beensufficient time since its formation forother
The Victorian naturalist . rther blocked by analluvial fan of granitic sand (Thomas,1937). The lake is 770 ha in area with acircumference of almost 15 km and isorientated with its major axis in aSW-NE direction. The floor is flat, butis slightly lower at the SW end. In-terestingly Bennett and Schwerdtfeger(1970) reported a lowering of thewater table towards the NW end, sug-gesting the possibihty of a leak thereassociated with faulting. However,the shape of the lake (Fig. 1) andbottom topography tend to deny suchan origin, but there has probably beensufficient time since its formation forother factors, especially wind defla-tion, to modify the morphometry ofthe basin. * Department of Zoology, Monash University,riayton. Victoria, 3168. Present Address—Sciences Department, Avondale College, Cooran-bong, 2265. 156 Vict. Nat. Vol. 92 Plate 1 Lake Omeo,viewed fromthe southwestcorner inNovember 1970. Photo, Author. Figure 1 Locality mapshowing LakeOmeo, LakeKing and thestock dam onMinute Creek, Photo, August, 1975 157 There is considerable secular fluc-tuation in the amount of water held inthe lake basin. It was full — thewater level up to a well-marked shore-Hne and 3 m deep — in 1896 and1956, but dry in 1870, 1914, 1937,1950, 1967 and 1972 (Bennett andSchwerdtfeger, 1970; Mr. W. Hol-lands, personal communication).During the last forty years a typicalcondition would be for it to be dryor to contain some water, particularlyduring spring. Bennett and Schwerdt-feger (1970) showed that the lakeaccumulates water only during excep-tionally wet years, since annual evap-oration is near 100 cm while averageannual precipitation is only for the full period follow-ing 1956, in the last forty years thelake has contained less water and beendryer longer than was the case in thelate 1800s and early 1900s (Bennettand Schwerdtfeger, 1970; Mr. W. Hol-lands, personal communication). Thiscondition would be associated withlong term rainfall fluctuation
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Keywords: ., bookcentury1800, bookdec, booksubjectnaturalhistory, bookyear1884
