The irrigation exemption provided by section 13(b)(12) applies to
``any employee employed * * * in connection with the operation or
maintenance of ditches, canals, reservoirs, or waterways'' of an
irrigation system which qualifies for the exemption. The employee, to be
exempt, must be employed ``in connection with the operation or
maintenance'' of the named facilities; other employees of the irrigation
system, not employed in connection with the named activities, are not
exempt. The exemption may apply to employees engaged in insect, rodent,
and weed control along the canals and waterways of the irrigation
system.