on the Colorado and Tijuana Rivers, in connection with the
division of their waters between the two countries.'2
Assumption of federal responsibility for control of floods on
a national basis is a relatively recent development. Although
beginning about a century ago, legislative evidence of federal
interest was long confined prii cipally to the Mississippi Valley.
In 1917 and again in 1928, s ch interest was accentuated and
broadened. Finally, Congrels in 1936 pronounced a national
flood-control policy and au horized numerous flood-control
projects throughout the Nati n. "Flood control" is defined to
include "channel and major drainage improvements."
In the main, legislation relevant here bears a marked simi-
larity to that governing navigation improvements. Thus,-in-
vestigations and improvements of rivers and other waterways
for flood control and allied purposes are prosecuted by the
Army Engineers. In the preparation of flood-control projects,
many laws concerning navigation improvements are expressly
made applicable. Similarly, authorizations of surveys, prep-
aration of reports thereon, cooperation with states and other
agencies, and review by the Board of Engineers for Rivers and
Harbors-all substantially follow the pattern applicable to
Projects may be undertaken only when expressly authorized
by Congress, and a number of laws have been enacted in the
nature of continuing authorizations: or specified types of work,
many allowing varying degrees of discretion in the use of funds.
Excepting dam and reservoir pro ects, law generally appli-
cable to authorizations for flood-control work requires that
states or other local interests provi e the necessary lands and
maintain local works.
With few exceptions, laws concerning funds and concerning
prosecution and operation of projects, including multiple uses,
are substantially like those governing navigation improve-
As to certain international water, two international com-
missions have functions concerning, among other things, flood
S59 Stat. 1219.