[Proc. Rot. Soc. Victoria, 21 (N.S.). I't. I., 19US.J 



Art. IX. — Geologii of tJie Proposed NillaJi cootie Water 

 Conservation Area. 



By H. S. summers, M.Sc, 



Government Research Scholar, Geological Laboratory. Melhonrne 

 University. 



(With Plate XIII. ). 



[Read 11th June, 1908]. 



I.— I^-TR0DUCTI0^^ 



Every dry season the Broken Creek, a branch of the Broken 

 River flowing into the Murray, ceases to run, and the result is 

 a water famine over most of the country lying between the 

 MuiTay and the Broken River. The inlet of Broken Creek 

 from the main river had gi'adually been silted up, and only flofid 

 waters found their way from the river into the creek. Matters 

 were considerably improved by the building of Casey's Weir, just 

 below the point where the flood bed of the creek left the river, 

 and by the cutting of a channel to allow more water to enter 

 Broken Creek. In time of extreme drought the Broken River 

 itself ceases to flow, and consequently even in moderate seasons 

 littlo or no water finds its way into Brokein Creek during the 

 summer months. It was therefore proposed to build a large weir 

 on the Bi'oken River at Nillaihcootie, half way between Mansfield 

 and Benalla, in order to conserve sufiicient water to keep the 

 Broken Creek cimtinually flowing, even in the dryest seasons, 

 and to supply water for irrigation purposes. A site for a weir 

 was selected just above the junction of Back Creek and the 

 Broken River, and bores and shafts put do\\'n in order to test the 

 n;iture of the underlying rock. The river at this point flows 

 along a gorge about fifty feet deep, cut through solid granite, 

 so that the foundations for the main concrete wall would br 

 perfect. 



