The 1976 drought

Cause

Persistent blocking high pressure over the British Isles across two successive summers and the winter between them, so the winter recharge that normally refills aquifers and reservoirs did not happen. The sixteen months to August 1976 were the driest such period in the England and Wales rainfall series, which begins in 1766.

Impact

• Flow on the Thames at Kingston fell to a monthly mean of about 1.9 m³/s in August 1976, against a long-term August mean of roughly ten times that
• Standpipes and rota cuts in parts of South Wales, Devon and Cornwall
• Devon and Cornwall lost mains supply for up to seventeen hours a day
• An estimated £500 million of agricultural losses at 1976 prices
• Widespread subsidence claims as shrinkable clays dried and moved

Response

The Drought Act 1976 was passed in August, giving emergency powers to restrict supply. A Minister for Drought was appointed. Rain returned in September and the following months were among the wettest recorded.

Aftermath

The event became the design drought against which English water resource planning was set for the next forty years, and remains the reference case in company drought plans. It also drove the interconnection of supply systems whose absence would prove decisive again in Yorkshire in 1995.