A feature of Jessop's canal engineering is his careful provision of sufficient water supply, and Butterley, covering 50 acres, contains enough water for 2,800 locks.

The reservoir was created using an earth dam, 300yd long and 150yd wide at base. The dam has a clay puddle core and is an early example of this type of construction. A stopcock fed water from the reservoir directly into the shaft of Butterley Tunnel. The tunnel partially collapsed in 1900, and canal traffic ceased in 1944.