It's amazing how water will keep flowing underground not far under the surface throughout winter even when it's well below freezing.
not that amazing. geothermal heating takes advantage of the fact that there is heat in the ground. i helped build a off grid home that used this principle. we insulated the basement walls with 6" of polystyrene between 1/2" plywood panels. this leaves the basement 1' smaller in length, and width while allowing the year round @•56 degrees earth to heat the floor. this saved a lot of energy when heating and cooling the building. get below 6' and i have no doubt it will be running water. (as long as the air temps are not too low in the well shaft).
