Would this work?

[tmyers]

I was just reading a thread on Pool Chillers. I know that a hole in the ground is much cooler than air temp. (My basement stays at least 15 degrees cooler) Has anyone ever dug a hole in the ground several feet deep and coiled water lines in it and covered it up to cool their pool?

 

[JasonLion]

Something along those lines can work, but a small hole such as what you describe would never work. A ground source heat exchange system typically requires something like a thousand feet of trenching, or a well of similar depth, and a heat pump to work.