Ever since the reservoir was created in 1974, the Guelph Lake conservation area has been popular for swimming and various beach activities.

There are changing facilities, and two man-made sand beaches at Guelph Lake; however, the park does not maintain a regular lifeguard patrol.

The concert area, which has a living roof, is located on a peninsula at the centre of the lake, and is the site of the annual Hillside Festival.

The dam at Guelph Lake is one of the main flood control installations on the Speed River.

Each spring, melt-water runoff and seasonal precipitation is collected in the reservoir; during the summer, water is released slowly to regulate the flow of the river; and in autumn, the lake is drained to a much lower level, before it freezes over (partially or completely) during the winter.