If your line is buried 16 feet deep, that is a major problem.
If you know exactly where the line is, you can drive a steel rod a couple of feet into the ground and put your ear to it. You can hear the water hissing when you get close to it. Don't know if it would work 16 feet deep, though.
Also, depending on the size of the line, you can insert a smaller line inside of it and push or pull it through. For example, you can put and 1 1/4 inch through a 2 inch line. Works for several hundred feet if you get a good place to work from.
Once in California, we had a leak from the water main in the street. Once they located it (by listening), they slipped a cable through the line. Attached was a spear shaped connector with blades. They hooked the new line on the spear and pulled the new line under the sidewalk and street. The spear split the old pipe and spread it out so the new pipe slipped right through the hole.
Also helped a neighbor slip a new black plastic pipe through an old steel pipe which went under a building and concrete.
If none of the above works:
We do our own pipelining. We rent a trencher (usually a Vermeer 8550 for $500/day) and dig a new trench. They will dig about 6 feet deep so that might not be enough depending on frost line. Depending on the soil, it will dig a mile a day.
If the water is for domestic, it won't be likely to freeze since there is usually warm water going through it every day.
