Climate change predictions inform us that while south east Britain will suffer more drought, the north and west will be vulnerable to stormier conditions, and so it has come to pass.Storms seem to be getting worse and flooding is becoming more common.This is a challenge to the infrastructure, some of which was constructed in the 19th century. Several of our dams were erected at that time. The engineering was excellent, but we knew less then than we do now, and materials were not as sophisticates. Dams were constructed to meet the demands of the climate then, and we must ask whether or not some need upgrading. There is also the problem of inferior upgrades done at a later time.
Late July 2019 was hot, and that month had been Britain's hottest month ever. Days of heat across the East Atlantic caused evaporation of sea water into the warm air, but then a low pressure system took over, the air cooled and the water came down as torrential rain. Some parts of Northern England suffered minor flooding, though the dry ground soaked up the water, but the waters had done some damage to the Todd Brook Dam. All dams must have a supervising engineer and an inspection engineer, who must inspect regularly, and when the latter performed his inspection he discovered damage. Concrete slabs that constituted an outer casing on the dam had been forced loose and a hole was developing in the dam wall. The Canals and Rivers Trust, who own all dams in England and Wales, were alerted, as were the police,and the emergency procedure was instituted
The town of Whaley Bridge is in a narrow valley with steeply sloping hills on both sides. It is centred on the river Goyt, though the dam, which is a small one, was constructed in 1831 as a reservoir to feed the Peak Forest Canal at a time when canals were a major artery for commercial goods. Since then its industrial use has faded, but it has become a leisure resource for local people and a site of special scientific interest. But if the dam collapsed a mass of water would deluge the pleasant little town and massacre many of those dwelling in the narrow valley bottom, before surging down the Goyt, thence to the Tame, a river in a heavily populated area, then down to the Mersey that flows through South Manchester [ a mile from my house!] and to the Irish Sea.The most damaging flooding would be local, but it could involve great loss of life and severe destruction.
Engineers believed that the dam was in imminent danger of collapse and so the police advised local people to evacuate immediately. Some went to evacuation centres,others to friends and relatives. A few refused to move. Then the work to make the structure safe began with urgency.