A better solution would be to run the water through some aluminum radiator coils,
and to mist water over the radiator coils. Perhaps run a water line through the pond,=
before going to the sprinkler system, that would help, again minimally.

If those aluminum radiator coils were buried somewhere cool, you'd have a heat
exchanger, and it would be effective. The challenge will be that the ground
gets pretty hot in AZ in summer. So finding that cool spot will be work, and
the digging will be deep.

C//