RAINFALL AND DISCHARGE OF THE MURRAY RIVER. LXXVII. 
would impound 33,381,000,000 cubic feet, or 766,320 acre 
feet. The calculations show the behaviour of a reservoir 
proposed to be formed by building a dam across the 
Murrumbidgee River at the site mentioned. It may be 
considered of interest in its bearing upon the subject 
matter of this paper as an example of the fluctuations of an 
impounding reservoir fed by an Australian river, and drawn 
upon for the purpose of irrigation during a period of unpre- 
cedented drought. 
Acting under the instructions of the Chief Engineer 
for Water Supply, the author has been charged with inves- 
tigations in order to prove on available data how the pro- 
posed reservoir would have behaved in supplying water for 
irrigation on the Riverina Plains some 300 miles below the 
site of the reservoir, and in providing a minimum volume 
for the use of lower riparian holders between the town of 
Narrandera and the junction of the Murray and Murrum- 
bidgee Rivers. In the investigation the irrigation 
requirements of one canal on the north, and one canal on 
the south side of the Murrumbidgee have been provided for, 
also provision for riparian flow to pass below the offtake. 
From the information so far obtained, it has been -calcu- 
lated that after commencing in January, 1900, with an im- 
pounded volume of 766,320 acre feet, the reservoir would 
have been drawn upon continuously owing to the dry summer 
and reduced at the end of March to 614,120 acre feet. The 
high river of the succeeding months would have rapidly filled 
the reservoir, overflowed it in July, and kept it so until the 
end of December of that year. The low rainfall of the 1901 
summer would have caused the reservoir to be drawn upon 
to a considerable extent, decreasing the depth of water by 
23 feet, representing a hold over volume of 506,408 acre 
feet. The winter rains would have replenished the reser- 
voir, filled it to overflowing in September, and retained it 
