I am new here. In search of some experience in a non-typical situation. I am a future homeowner looking at installing a Geothermal system for the home. My geothermal contractors are unsure about what I have and are desiring to over engineer the ground loop and spend too much of my money. The property has a small river running through it. In many parts of the country you would call it a creek. There is a small pond on the property. It is dug into what once was dredge tailings from dredge gold mining in the 1800s. A hydrology engineer told me the pond water is there as part of the river alluvium. Basically, the part of the river that is below ground, but nominally at the same level as the river itself. My observations are, and the engineer confirmed, that the water in my pond is part of the river system. It actually visually flows in the same direction as the river. There has been no observation of the river ever being dry in the channel. It is constantly moving in the pond. The pond was never frozen this past winter, even with extended periods of cold near 0 degrees F. I took temperature measurements during the winter and the pond surface temp was 39 degrees to 42 degrees throughout the winter. If you want to get a pictorial, look up on Google Earth: 123 Davenport Loop, Breckenridge, CO. You'll see the river running through the north(east to west) and the pond toward the west end of the property. What I am thinking I would do is use the currently excavated pond as a hybrid river loop. Since the water is continuously being exchanged by the moving water in the river alluvium, I have a similar environment to a river loop. I would place the loop as a slinky in the pond, then cover with a material with porosity to not inhibit the flow, and then fill in pond. (it is not very attractive). I would gain the advantage of not needing as much length as the Geo guys are thinking as well as having a pre-excavated pit. They proposed 500 feet per ton as if this was a standard horizontal ground loop. (I need 14 tons of capacity for heat only, no cooling load). My reasoning is my loop will pull the cold out of the loop quickly because of the moving water in the alluvium. My questions specifically are: 1) Am I crazy here that the river alluvium is truly similar to a river loop and I will have as good of heat exchange as I desire? If I am crazy, please tell me why. 2) If I were to bed the loop in a material, what should it be? Sand? Coarse sand? Pea gravel? How do a we balance the benefits of the bedding material for optimizing water flow but minimizing any potential damage to the loop? 3) As anyone else have a working model that has a similar ecosystem? What are your experiences? I look forward to hearing from you all.