should be divided between these two methods 
of approach, but it has now pretty generally 
come to be recognized that while both are im- 
portant, the most effective thing to de is to 
stop the trouble at its source, rather than 
to rely so much on ergineering works lower 
down, which after all are alleviative rather 
than preventive in character. Perhaps the 
most significant thing about all this work is, 
however, that it is now recognized a given 
stream must be treated as a unit, from its 
highest source way up on the mountain 
sides down to the point where it joins a large 
river in one of the broad and gently sloping 
valleys of the plains. 
EXAMPLES OF 
STREAM CONTROL WORK 
Perhaps as interesting examples of the 
control of torrential streams through engi- 
neering works as can be found anywhere in 
as near as 100 feet. On less abrupt gradients 
the dams are farther apart though still num- 
erous. The length of the stream bed that 
must be so treated often runs up to several 
miles. It will thus be seen that, the construc- 
tion of dams, or barrages, is an expensive pro- 
cedure, even with the lower prices for labor 
that obtained before the war. 
But this is not all. In the case of the 
worst torrents the streams have to be walled 
in, wing dams constructed to deflect the over- 
flow in times of unusual freshets, and in some 
instances the entire bed of the stream between 
its retaining walls, has to be substantially 
paved with stone blocks to withstand the ero- 
sive pounding of the rocks and other waste 
that is carried along by the rushing waters. 
A typical stream is the torrent of Saint 
Julien in this valley. Up to 1913 over $129,- 
000 had been expended on engineering and 
tree planting work in connection with its 
BED OF A 
TORRENTIAL 
STREAM 
HIGH UP THE 
MOUNTAIN 
BROKEN 
BY SMALL 
DAMS 
TO PREVENT 
EROSION 
France are to be seen in the valley of Saint 
Jean de Maurienne, east of Chambery, in the 
Department of Savoie. It is through this 
valiey that one of the main continental rail- 
roads winds its way, finally to plunge through 
the Mt. Cenis tunnel and emerge in Italy. It 
is a narrow valley. On either side rise high 
mountains with steeply sloping sides. The 
many branched ravines that run well back 
toward the summits of the ridges form ideal 
channels for concentrating the run-off from 
the heavy precipitation. The result is that 
immense volumes of water rush down the 
stream courses and, if not controlled, work 
havoc to everything along their path. 
To meet this situation the French forest 
engineers construct elaborate masonry dams 
across the stream bed to break the force of 
the waters. The height of the dams and their 
distance apart depend on the gradient of the 
stream, the object being to secure a series of 
nearly level steps. Where the grade is steep 
the dams must be close together, sometimes 
correction. And this was for a single stream, 
one of many in the valley. The longer cor- 
rection work is put off the more it costs 
when it is done. The old adage about the 
ounce of prevention was never truer than 
when applied to the work of reboisement. 
Of similar character, though less elabor- 
ate, are the corrective works farther up- 
stream. Here dams made of timbers are 
used. Higher up still, logs laid lengthwise 
with the stream are fixed firmly in place 
across the bed, but always with the idea of 
making a series of steps that shall break the 
force of the torrent. On the upper reaches 
of the streams, too, wattle work, consisting 
of small poles woven in and out between up- 
right stakes, replaces the masonry side 
walls. But even so it is work that quickly 
runs into money and that would not be un- 
dertaken were it not absolutely essential. 
In Switzerland, as well as in France, in 
the region of the High Alps, torrent control 
(5€) 
