204- DE RANCE: rXDERCROrXD WATER-SUPPLY AND RTVER FLOODS. 
the compeusation reservoirs were exhausted, to supply mill-owners 
with pure spring water, whilst human beings had to be put on 
short supply. 
The amount of " average flow " of a stream will be found to be 
far below the volume that would be yielded by a third of the annual 
rainfall, and the disparity is still greater when the "dry weather flow" 
of the stream is compared with a daily average of one-third of the 
annual rainfall, pointing to the necessity of regulating tlie floods, 
which inflict a three-fold loss, first, by destruction of property in the 
lowlands ; second, by depreciation of tlie value of agricultural 
produce, and the stoppage of manufacturing processes by its absence ; 
third, the loss of vital energy, and the premature death of those 
whose business and occupations compel them to live in areas subject 
to floods. 
When the far-reaching influence of uncontrolled water is studied, 
the constant drain tliat is made by floods on the health, life, and 
wealth of the kingdom will be realized, and the necessity of sweeping 
away the conflicting authorities that have control over our river 
basins admitted ; these at present are multifarious in number, 
antagonistic in character, and often injurious in efl'ect. The River 
Witham and its chief tributaries, for instance, is under the jurisdic- 
tion of 17 separate authorities, without including the various Drain- 
age (yommissions of the Fenlands, that would bring up the number to 
forty, while the River Lene, according to Sir John Goods, on only 30 
miles of its course, between Peterborough and the sea, is overridden 
by no less than fourteen authorities. 
Mill and Navigation Works affect rivers chiefly through weirs, 
obstructions fixed across a stream, with a view to prevent water 
passing on until it has attained a certain head ; that height attained, 
its surplus water passes over the weir, in times of ordinary flow, with 
a more or less considerable fall. Landowners require a uniform top- 
level, neither too high to flood the meadows or too low to deprive 
them of moisture. Navigation requires the water to be penned back 
to make the upper reaches navigable, whether the land below suffers 
or not ; whilst fishing owners maintain their right at their o^vn con- 
venience to raise the top-water to its highest limits, and then 
