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An Automatic River Gauge. 

 By Thomas Parker, C.E. 



[Read July 3rd, 1888.] 



Since the reading of my paper on " Underground Waters" 

 before the Society last year, in which I drew attention to the 

 great need of a systematic gauging of the rivers and streams of 

 this colony, I am glad to learn that the Government have given 

 instructions for this work to be undertaken. 



During the course of my labours in gauging one of our rivers 

 by the usual method, I was led to attempt some improvements on 

 the existing system of taking such observations, and as a result, 

 have designed an automatic river gauge. My object in this paper 

 is to give a description of the invention, the method of using it, 

 and also point out what I think are its advantages in point of 

 economy and efficiency. 



I will first briefly describe the present methods of gauging 

 rivers. 



The usual methods of gauging rivers are — (1) By current 

 meter, and (2) by a weir and graduated scale. The first method 

 is that generally used for large rivers where a weir does not exist 

 or is not easily erected. It is now being used by the various 

 colonies in gauging the River Murray. It is a portable instru- 

 ment, and so constructed that on being dij)ped in the stream the 

 working parts are caused to revolve by the flow of the water, and 

 the velocity of the river flow is indicated by the number of revo- 

 lutions made and indicated by the instrument. This velocity ap- 

 plied to the sectional area of the stream at the point where the 

 observations are taken enables the observer to calculate with suf- 

 ficient accuracy the volume of water discharged by the river in a 

 given time. 



The second method, namely, gauging by means of a weir 

 erected on the river, is usually applied to smaller streams, and it 

 is to the improvement of this method my invention is intended 

 to be applied. In this case a weir is erected across the river, and 

 a lath set up marked ofl" in inches and decimal parts, and read- 

 ings of the height of the water above the sill of the weir are taken 

 from time to time, and from these, by the aid of the usual hydraulic 

 formula? applicable to the stream, the quantity of water passing 

 over the weir at any particular time may be calculated. The 

 great drawbacks of this system are its inefficiency and costliness. 



