of injured credit. Roughly
estimating the damage as a whole, and taking into consideration factors
which were given to the writer confidentially, the damage throughout the
drainage area from this flood will amount to not less than $7,000,000.

PREVENTIVE MEASURES.

GENERAL DISCUSSION.

In the consideration of means of preventing damages by floods every plan
proposed falls under one of two general heads--the storage of flood
waters or an increase in the capacity of the streams.

The first plan involves the construction at selected localities of
reservoirs of sufficient size to hold all or a greater part of the
waters which run over the surface during and after storms. This plan is
not practicable except where valleys or plains are inclosed by high
ridges and these ridges approach sufficiently near each other to admit
of the economical construction of a bank or dam across the gorge or bed
of the stream which flows through, so that the inclosure will be
complete and form a water-tight basin. Where such a reservoir exists the
water can be held back and gradually let down through properly provided
gates so that the channel will not be flooded.

For flood purposes alone it would be necessary to provide reservoirs of
sufficient capacity to contain the run-off waters resulting from the
largest storms. With such provisions it would be necessary to entirely
empty the reservoir as soon as possible after a storm had passed and
leave its full capacity available for the next storm. It is therefore
better, wherever possible, to provide a reservoir capacity considerably
larger than that represented by the run-off from the heaviest storms, so
that water may be stored for use as power or domestic supply. With such
provision it is necessary merely to draw from the reservoir water to a
depth equivalent to the stream run-off in the drainage area above.

The second plan for prevention of flood damages involves provisions for
letting the flood water out rapidly by removing obstructions to its flow
by straightening and deepening the channels and providing long
embankments, dikes, or levees which rise above the ordinary river level
to a height exceeding that of the stream during its highest floods. This
plan is most generally followed in the case of large rivers like

* * * * *

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

[Illustration: _A._ DEVASTATION IN HEBREW QUARTER, PATERSON, N. J.]