406 REPORTS ON THE STATE OF SCIENCE, ETC. 
was built in the river bank, into which a seven-day Lea Recorder was 
installed to measure the rate of flow. ‘These observations were discontinued 
in September 1921, but Mr. Roles thinks this gauging station could be 
re-established at a cost of £50 to £100. 
In regard to underground water, some information is also available in 
respect of wells at various power stations, but no systematic flow measure- 
ments appear to have been made. 
AppENDIx D (4) (a). 
GAUGING OF THE RIVER SEVERN AT IRONBRIDGE 
BY THE WEsT MIDLANDS JOINT ELECTRICITY AUTHORITY. 
By E. F. HETHERINGTON. 
Ironbridge power station has been designed for an ultimate capacity of 
200,000 kw., consisting of four 50,000 kw. maximum: continuous-ratéd 
machines. When the construction of the station was under consideration 
in 1925-26 rough measurements of the river flow were made. In 1927 a 
further set of measurements was made, and a third survey was completed 
in the summer of 1928 after a long dry spell, when the flow was at its 
minimum. The result of these measurements showed that even undér 
the extreme conditions prevailing in 1928 there was sufficient water for the 
operation of three generating sets at full load, the fourth acting as a standby. 
Since that date constant observations have been taken, and a complete 
record of the daily river levels from June 1929 to the present day has been 
kept and a curve plotted. 
The Authority is quite satisfied that during eight or nine months of the 
year there is more than sufficient water for the operation of 300,000 or 
400,000 kw. of plant, and this being the case they have never troubled 
to gauge the river accurately at the higher rates of flow. 
The method of gauging adopted was to select a certain stretch of the 
river and make an accurate survey of its depth. The particular length 
chosen for this purpose had practically the same depth contour throughout, 
and this considerably simplified measurements. The floats were designed 
and made of a type indicated on a plan which is available, if required. 
These floats consist of a kind of boat-shaped raft with a sinker weight, which 
could be arranged to hang down into the water at any desired depth, by which 
means a more or less mean velocity could be obtained between the surface 
of the water and the flow nearest to the river-bed. Levels were very 
accurately taken by theodolite, and lines were placed across the stream at 
two points, (a) and (b). The floats were timed over the course, and a 
velocity table attached indicates the rates of travel down stream. From 
time to time intermediate timings were taken, which clearly showed that 
the floats traversed the whole length of the course at a constant velocity. 
The cross-section of the river (copy available if required) worked’ out at 
448 sq. ft., while the mean velocity of flow, as indicated on the table attached, 
was found to be 0-849 ft. per second, and taking the number of gallons per 
cubic foot as 6°25, the quantity of water was 
448 X 0:849 X 6:25 X 3,600 = 8,580,000 gallons per hour. 
The Authority has not troubled to take very accurate measurements of 
the higher rates of flow, although a number of tests have been made from 
time to time, from which it would appear that the normal summer flow of 
the river at this point is in the region of 12 million gallons per hour, 
(Table of measurements accompanies original statement.) 
