Anyone know about "water source" heat pumps?

[Eurekan]

While not exactly what you wanted there is a way to use free running water to dramatically improve the performance of a Heat Pump/AC.  There is a swimming pool heat exchanger that would work in your situation.  This is intended to heat a swimming pool but I see no reason why you couldn't use something like this year round. http://www.poolheatersinc.com/free-pool-heat/

[EricU]

The OP is not describing a water source heat pump system.  He is describing a chilled water scenario.

yes, it's far more effective to dump heat into the water than to try to cool air with the water. For that, you need a compressor.

In Utah, we had a swamp cooler like everyone else. It pulls air through filters that are kept wet. Unfortunately, when you really need it, the physics doesn't work that well.  I swear any time it hit 100F, the humidity would hit 50 percent and poof, no cooling from the swamp cooler.