The permanent benefits accruing from the E.C.W. rodent-control program
have been enormous from the standpoint of erosion control alone. An
associate range examiner of the Forest Service has the following to say
regarding the effect of rodents on erosion in the Boise watershed of
Idaho:
"Rodents, numerous and spreading over nearly 80 percent of the Boise
watershed, have undoubtedly been responsible for no small part of
the present erosion. Wholly dependent upon the herbaceous plants for
their food supply, their tremendous numbers, along with over-grazing
by livestock and unfavorable climate, have been an important
contributing factor in depleting this cover, and thus have greatly
reduced the protection afforded the soil and subjected it the more to
increased sheet erosion. Even light rains on rodent-infested areas
are likely to start cutting, which may develop into destructive gully
erosion because of the almost immediate accumulation of run-offs in
the myriads of burrows and channels which these animals construct
just under the surface of the soil."
The control of rodents is vital to the successful operation of
reclamation projects in the western third of the United States.
Rodents, particularly pocket gophers, find the banks of irrigation
canals an ideal location for their burrows and runways. These
subterranean passageways frequently are the cause of serious breaks
in canals, through which the flow of irrigation water is diverted
and wasted to flood adjacent lands, destroying valuable crops, and
indirectly ruining others by causing delays in delivery of water.
Through the E.C.W. program, C.C.C. crews working under the direction
of experienced foremen trained by the Biological Survey have greatly
reduced this menace. In the past year alone half a million acres of
canal banks and contiguous lands were treated by C.C.C. rodent-control
crews with a thoroughness that will be of lasting benefit to the
nation's reclamation projects.