THE IRRIGATION AGE. 



The weir is built of large blocks of con- 

 crete bonded as in ordinary masonry and 

 laid in cement mortar. This course was 

 adopted in preference to the ordinary 

 method, as it was considered that should a 

 crack start, there would be less danger of 

 it traversing the structure from top to bot- 

 tom than were it monolithic. 



The waterway in the upper portion of 

 the weir is occupied by twenty-one flood- 

 gates, each having a clear opening of 

 twenty feet by ten feet. These are lowered 

 into recesses or chambers in the body of 

 the work, and can be so adjusted at any 

 time as to maintain a constant level of 

 water in front of the offtakes. Wrought 

 iron ribs and braces have been worked into 

 the concrete in front of the gate chambers 

 to strengthen it at these points. 



The gates which are framed of wrought 

 iron beams filled in with cast-iron plates, 

 each weighing about seven tons, are 

 worked by screw gearing. The gate pil- 

 lars, are of cast iron, hollow and filled with 

 concrete. They are strongly secured by 

 anchor plates and holding down bolts, and 

 occupy about two feet of the waterway. 

 The gearing for raising and lowering the 

 gates is actuated by three thirty and a half 

 inch "Leffel" turbines. These can be 

 worked together or separately, and anyone 

 or all three can be put in gear with any 

 gate or gates. Hand gearing is also pro- 

 vided in case of emergency. A separate 

 turbine drives generating machinery for 

 electric light consisting of five arc lamps. 

 These are necessary in order that the gates 

 may be adjusted at night should the height 

 of the river fluctuate. 



REGULATORS. 



In continuation of the weir are two reg- 

 ulators for the channel offtakes, one on the 

 east and one on the west. These are of 

 similar construction to the weir and are 

 provided with cast-iron gate standards 

 which also carry a light bridge. The 

 western regulator has fourteen gates, each 

 nearly ten feet clear opening with a height 

 of seven feet. The eastern regulator has 

 only four gates of similar dimensions. 



CHANNELS. 



In connection with the weir, a channel 

 upward of twenty miles long has been 

 excavated, from which the trusts to the 

 west of the Goulburn river derive their 

 supply. The bottom width of this chan- 



nel is 110 feet and side slopes of one and a 

 half to one. The gradient is six inches 

 per mile, and it has a carrying capacity of 

 103,400 cubic feet per minute when run- 

 ning full. The eastern channel has not 

 yet been constructed; it will be of much 

 less capacity than the western. When 

 both channels have been constructed it is 

 estimated that 125,000 cubic feet per min- 

 ute can be sent down during five months 

 of the year, and assuming the construction 

 of certain subsidiary storage basins, a total 

 area of 416,000 acres can be irrigated to a 

 depth of fifteen inches, after allowing a 

 large margin for evaporation and infiltra- 

 tion. 



COST. 



The total expenditure on this splendid 

 work to date has been 491,000 ($2,455,- 

 000). Maintenance expenses come out at 

 about 2,500 ($12,500) a year. Part of 

 this sum has been used in lining portions 

 of the channels which are of earth. In- 

 deed, maintenance charges should be a 

 minimum on a work of this substantial 

 character. 



The foregoing description has been 

 largely taken from a descriptive memoran- 

 dum of the weir, compiled by the Chief 

 Engineer of Water Supply, Mr. Stuart 

 Murray, under whose supervision the 

 works were designed and executed. 



LAANECOORIE WEIR. 



This weir is situated on the Loddon 

 river about half a mile above the township 

 of Laanecoorie, and is for the purpose of 

 impounding and regulating the flow of 

 water in that stream. No channels are in 

 direct connection with the weir, which is 

 solely used for regulating the supply in 

 the river bed itself, the offtakes to the 

 trusts' channels being some twenty miles 

 lower down. Six trusts are dependent on 

 the water here conserved for their supply. 



DESCRIPTION OF WORKS. 



The portion of the structure in the river 

 channel itself is of concrete, with automatic 

 lifting gates for the discharge of heavy 

 flood waters. There is an extension on the 

 left bank in the form of an earthen dam, 

 protected in the rear by a banquette of 

 materials not liable to scour, and on the 

 face by broken stone up to within six feet 

 of the permanent water level, above that 

 with concrete pitchers. The length of 

 crest of main weir is 324 feet, provided 



