There is an artificial pond located near a great lake. The pond is connected to the main lake through a small channel, which is used for water intake. In winter, the pond is used as a storage reservoir. What is the purpose of the small channel connecting the pond to the main lake?
1) To provide a source of water for the pond
2) To drain excess water from the pond
3) To prevent the pond from overflowing
4) To allow fish to migrate between the pond and the main lake