The image is a diagram illustrating the structure of a lake, specifically a reservoir. The diagram shows three main sections: the reservoir, the dam, and the reservoir below the dam.

1. **Reservoir**: This section represents the body of water that is being used for storage. It is depicted as a large, rectangular shape filled with water.
2. **Dam**: This section shows a dam that separates the reservoir from the reservoir below it. The dam is depicted as a solid structure with a vertical wall.
3. **Reservoir Below the Dam**: This section shows the lower part of the reservoir, which is connected to the reservoir above it by a pipe or channel.

The diagram also includes some additional elements:
- **Cotton Lake**: This is a smaller, rectangular shape located at the top of the reservoir, indicating a smaller body of water.
- **Mineral Springs**: These are depicted as a smaller, rectangular shape located at the bottom of the reservoir, indicating another smaller body of water