Final answer:
The possible reason for the high alkinity in the well water could be that the well is located near a limestone deposit.
Step-by-step explanation:
The possible reason for the high alkinity in the well water could be that the well is located near a limestone deposit. Limestone is a type of sedimentary rock that is composed mainly of calcium carbonate. When water comes into contact with limestone, it can dissolve the calcium carbonate, which increases the alkalinity of the water.