IT had already been a wet month. So, after more heavy rain overnight, drivers heading along the A677 Blackburn-Haslingden road cutting through the farm country above Oswaldtwistle just after dawn on that November day 29 years ago were hardly surprised to find slight flooding half-way along the road.

Cars got through the water without problem, but some of the more public-spirited motorists reported the flooding to the police so that others could be alerted.

It was a gesture that was rendered redundant within minutes of those first calls coming in - as the troublesome trickle flowing across the road turned into a raging, roaring maelstrom 100 yards wide.

"It sounded like an earthquake," said one of the first workmen on the scene.

And, indeed, its impact on the road was as devastating. The rippling brook that ran in a culvert deep beneath it was now a continuous mud-filled tidal wave hurtling several feet above the road and ripping open a 30ft-deep hole in its side.

It was an awesome instance of the power of water - all unleashed in minutes when half a mile above, high on the hills above Oswaldtwistle, the bank of a reservoir had burst, sending a deluge of 25 million gallons crashing down.

The first obstacle in its path had been the road. The savagery of its force could be gauged by the tremendous noise of the torrent and the ground alongside it shaking, but its true effect would not emerge until later when its intensity eventually waned and the was damage revealed.

Meantime, the consequences literally poured downhill in the direction of Oswaldtwistle. The wall of water that escaped from the Warmwithens Reservoir plunged into Cocker Cobbs Reservoir standing just beneath the A677, instantly overflowing it and sending its contents on down a raging river and into Jackhouse Reservoir just a few hundred yards away.

In turn, it spilled over into the normally-tranquil Cocker Brook outflow and the torrent hurtled on downhill into Jackhouse Brook and towards the Three Brooks Mill of Rhoden Dyeing Company standing on the bank of Tinker Brook. There, as the deluge threatened to swamp the works, 30 employees were sent home by the firm. Next door at Gaskell and Co's Rhoden Mill, workers hurriedly filled sandbags to keep out the flood while police with loudspeakers toured Oswaldtwistle alerting householders and schools of the danger.

After three hours, the emergency was over. The breached reservoir that had begun it was virtually empty.

The ruined road, looking like it had been hit by a giant bomb, took weeks to repair and re-open.

For days afterwards residents in Church and Oswaldtwistle had to get water supplies from mobile tanks as that from their taps was the colour of milky coffee - because the silt stirred up by the maelstrom in the Cocker Cobbs and Jackhouse reservoirs was so fine that it went through the filters into the mains.

The wall of Warmwithens Reservoir looked like it had been cleft by a gigantic axe. But why it had given way was a mystery. At the time, it had been full, but not excessively so. And though it had been constructed early in the 18th century, it had been reconditioned only four years before it burst and had in the interim been full several times before, without problem.

Eventually, it was concluded - after a £220,000 repair plan was dropped and the reservoir abandoned - that it was a victim of old age, but its last moments had brought three hours of terror.

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