[Illustration: _B._ A COMMON EXAMPLE OF FLOOD DAMAGE.]

U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 92 PL. VII

[Illustration: _A._ INUNDATED LANDS AT PASSAIC, N. J.]

[Illustration: _B._ UNDAMAGED BRIDGE ACROSS PASSAIC RIVER AFTER PARTIAL
SUBSIDENCE OF FLOOD.]

* * * * *

the Mississippi, where the contributing area is enormous and the
conservation of the waters would be impracticable even if the nature of
the country would admit of the construction of reservoirs. In
Switzerland, where the torrents occasioned by the rapidly melting snows
are especially destructive, the flood waters are confined by a series of
parallel dikes on each side of the river, which have the effect of
dividing the flow into several parallel streams. As the main river
channel fills and overflows the inner dikes, the overflow water collects
into the first series of parallel channels, and when a height is reached
at which the second dikes are overflowed the water collects into the
third, and so on. This gives an enormous carrying capacity, the limit of
which is approached slowly, and therefore abundant opportunity is
afforded for preparation upon the part of the riparian owner.

The drainage basin of Passaic River is admirably adapted to the
development of the conservation system. At its headwaters in the
mountains of northern New Jersey are numerous sites for reservoirs. The
comparatively limited area draining into Passaic River makes such a
scheme relatively inexpensive. On the other hand there is abundant
opportunity for effective work in removing obstructions and
straightening and deepening the channel of the lower river. So that, all
things considered, the prevention of flood damages in the Passaic Basin
can be best accomplished by a combination of the two general methods
above outlined.

LOWER VALLEY IMPROVEMENTS.

The channel of Passaic River below Great Falls, at Paterson, is of
limited capacity. To anyone making an inspection, especially within the
city of Paterson, it is readily apparent that the river bed has for
years been considered a legitimate field for encroachment. Owners of
lands fronting on the river have increased their holdings by filling in
beyond the channel line. Buildings have been erected upon these tracts
and the builders have not hesitated to extend retaining walls still
farther into the river bed. Refuse from the city's streets, light and
unstable in character, has been f