410 REPORTS ON THE STATE OF SCIENCE, ETC. 
to ascertain the rate of rise in the reservoir due to ‘ run-off’ from the 
rainfall. 
Of the amount of feed water that is ‘ kept on’ to supply the requirements 
set out under (a), (0d), (c) and (d). 
Of the amount of feed water that is ‘kept on’ at the individual locks 
together with recorded levels of the reaches both on up- and down- 
stream sides of the lock. 
Of the number of lockings that occur daily at each lock. 
5. So far as the ‘ combination of artificially cut canal and canalised river ’ 
is concerned, in this case no doubt fairly extensive weirs will be constructed 
on the various reaches for carrying away flood water, so in this type it 
would be desirable for records to be kept :— 
At each lock of the level of the water in the reaches (up- and down-stream), 
Of the amount of feed water that is ‘ kept on.’ 
Of the daily number of lockings at each lock. 
Of the height of the water passing over the several weirs during normal 
and flood periods. 
6. This introduces another subject which will certainly arise, i.e., what 
is the formula to be adopted for the calculation of the amount of water 
passing over the weir under various heads, and it is suggested that a very 
useful amount of experimental work could be carried out by gauging the 
flow in the artificial cuts carrying away the weir water to ascertain how the 
coefficient of discharge varies according to the types of weir constructed. 
7. So far as the ‘ canalised river ’ is concerned, the measurements required 
will be practically similar to those necessary for the immediately preceding 
type, except that in all probability the weirs will be longer and larger, 
and we may also have the problem of mills being constructed athwart the 
river and absorbing a large amount of water, and arrangements for measuring 
the amount of water they consume should also be made in addition to the 
measurements to meet canal requirements. In many cases millers are 
responsible for the river and/or canal water level being kept too high or 
run too low in the several reaches both as regards canal working and also 
as regards the standing surface water level of the surrounding land. 
8.,Of the various sources of supply mentioned in paragraph 3, only 
the first has a sufficient and efficient organisation in existence to supply 
the necessary data ; the others are only dealt with by canal authorities to the 
extent that the efficient working of their canal demands. 
9g. No doubt the various canal authorities have a lot of information 
available, but whether they would be prepared to consent to this information 
being supplied to a co-ordinating body set up for the purpose is one that 
would have to be very tactfully ascertained from them, and this would 
form a suitable subject for discussion with the main Committee of which 
we are a Sub-committee, to ascertain from them how far they consider the 
matter should be pursued. 
SuB-MeEmoraNnpDuM D (6). 
WATER POLLUTION AND RIVER GAUGING. 
By A. PARKER. 
GENERAL. 
Accurate information regarding the flow of rivers and streams, river levels 
and underground sources of water is of value not only in connection with 
