Yes - you can see the gray water lines along with the natural gas line...
Those 2 lines go to a cooling coil which circulates the engine cooling fluid in copper coils with the irrigation water out of the well flowing over the coils... Works slick as a whistle and doesn't waste any extra hp like running a fan would.
I had an engine on a big well one time that could barely pull it - and I was having trouble with it heating - so I added a fan to help with the cooling - and was surprised to see how bad that hurt me on the barely-enough-power problem. I wound up buying a bigger cooling coil assembly & took the fan back off in that instance.
I also would usually take the thermostat(s) out and just put a plate with a hole drilled in it (5/8" or so) - and that would be about right to keep it at the right temp - and then I didn't have to worry about sticky thermostats or anything. Since the loads stay so constant over long periods, it works fine for irrigating.