e the
obstruction to navigation, is not a taking of property within the
meaning of the Constitution.[276] The exclusion, from the amount to be
paid to the owners of condemned property, of the value of improvements
made by the Government under a lease, was held constitutional.[277] An
undertaking to reduce the menace from flood damages which was inevitable
but for the Government's work does not constitute the Government a taker
of all lands not fully protected; the Government does not owe
compensation under the Fifth Amendment to every landowner whom it fails
to or cannot protect.[278]

When Property is Taken

According to the Legal Tender Cases,[279] the requirement of just
compensation for property taken for public use refers only to direct
appropriation and not to consequential injuries resulting from the
exercise of lawful power. This formula leaves open the question as to
whether injuries are "consequential" merely. Recent doctrine embodies a
more definite test. In United States _v._ Dickinson,[280] the Supreme
Court held that property is "taken" within the meaning of the
Constitution "when inroads are made upon the owner's use of it to an
extent that, as between private parties, a servitude has been acquired
either by an agreement or in course of time."[281] Where the noise and
glaring lights of planes landing at or leaving an airport leased to the
United States, flying below the navigable air space as defined by
Congress, interfere with the normal use of a neighboring farm as a
chicken farm, there is such a taking as to give the owner a
constitutional right to compensation.[282] That the Government had
imposed a servitude on land adjoining its fort so as to constitute a
taking within the law of eminent domain may be found from the facts that
it had repeatedly fired the guns of the fort across the land and had
established a fire control service there.[283] A corporation chartered
by Congress to construct a tunnel and operate railway trains therein was
held liable for damages in the suit by an individual whose property was
so injured by smoke and gas forced from the tunnel as to amount to a
taking of private property.[284]

Navigable Waters

Riparian ownership is subject to the power of Congress to regulate
commerce. When damage results consequentially from an improvement of a
navigable river, it is not a taking of property, but merely the exercise
of a servitude to which the property is always subject.[285