Dam Failure Case Study: Toddbrook Reservoir Dam (England, 2019)

Toddbrook Dam (sometimes referred to as Whaley Bridge Dam) was constructed in 1840 with a single spillway at the left abutment of the dam. In 1964, the spillway was damaged during a flood event. This damage led to modifications to increase spillway capacity, and a concrete auxiliary spillway chute was constructed on the downstream fill. During a flood event in 2019, a single slab of the auxiliary spillway chute collapsed into a large void that had formed underneath. The void then enlarged (removing some of the downstream shell material), and more slabs collapsed, risking the integrity of the dam. More than 1,500 people were evacuated in the town of Whaley Bridge for six days. An immediate drawdown of the reservoir was initiated, and urgent measures were taken to stabilize the dam.