and the Storage of Water. 
must be clearly proved to the satisfaction of the Inclosure Com- 
missioners that the works will effect a permanent yearly increase | 
in the value of the lands on which they are situate, or will ( 
produce a revenue exceeding the yearly amount proposed to be . I 
charged thereon. 
The several Acts of Parliament above enumerated give all ! 
the power that is required for the proper maintenance and , 
improvement of the tributary streams, water-courses and drains 
of the country, which form the subject of this article. What is J 
now required is a general Act, constituting Boards for the con- , 
servancy of the rivers of the country, and a proper system of ' 
uniform management and control from their source to their ' 
outfall, so that the wants of the various conflicting interests I 
should be fairly represented and dealt with in such a manner ' 
as shall tend to the general good. I 
I 
j 
Supply of Water to Rivers. i 
Rainfall. — As the rain produces the water which has to be | 
dealt with, it is a first essential in all drainage matters to , 
procure accurate data as to the amount which falls in the | 
district in question. This varies very considerably according to 
the situation and physical surroundings. The average of all 
England and Wales may be taken at about 32 inches. On the 
west side of the island, owing to the prevalence of westerly winds 
bringing the clouds across the Atlantic, and to the range of hills 
which bar their progress, the rainfall amounts to about 40 inches 
a year. In the Lake district, amongst the Cumberland hills, it 
rises as high as 165 inches. On the east coast, owing to 
opposite causes, the average fall is only about 25 inches, falling 
as low as 20 inches in the Eastern Midland division.* 
However interesting and necessary in procuring data average j 
calculations may be, they must be discarded in making provision : 
for drainage or water-supply, and the extremes of wet or drought I 
must be provided for. As a guide, however, it may be taken j 
almost as an invariable rule that if the average of any district j 
in England be taken for twenty years, and one-sixth deducted j 
or added, the result will give respectively the average of three 
minimum or maximum years. j 
Flow. — The flow of water in English rivers in mountainous 
districts varies ordinarily from extreme dry seasons to extreme 
floods three-hundredfold, and even in exceptional cases as much 
* ' Tlie Distribution of Rain over the British Isles.' By G. J. Symons ; published 
annually (Stanford and Co.). 'Rain: How, When, and Why it is Measured; 
being a popular account of Rainfall investigation.' By G. J. Symons {idem). 
i 
