Floods and Freezings
Some past weather events in and around the Medway Valley make our recent spell of wintry weather seem positively tropical. In 1814 for example, rivers across England were solid, thick with ice and able to withstand the weight of a horse and cart (Ogley et al 2007). At this time heavy snow and freezing conditions had resulted in a frozen Medway and when this began to break up it sent mini icebergs downstream!
The Medway flows over 100 miles from its source to its mouth, along the way as it flows eastwards, the gradient of the land drops and tributaries are created across the Weald of Kent. These river systems respond quickly to rapid rainfall and often demonstrate extremes of flow. In addition, the regional clay soils contribute to the quick changes which can occur under heavy rain. Subsequently the Medway has flooded many times over the centuries, often with devastating results:
On the 24th January 1846 for example, the bridge between Penshurst and Tonbridge collapsed due to a flood and resulted in the derailment of a train and the unfortunate death of Mr Dolby, the train driver. Other floods have happened several times along the Medway. Records include the flooding of Maidstones Mason Brewery on Saturday 13th February 1925 and two people being rescued from Fowle Hall in Paddock Wood in November 1935 after yet more torrential rain.
Most of the flood occurrences have been caused by the Medway breaking its banks under the pressure of heavy rainfall, but in late January/early February of 1953 the sea itself attacked. The sea wall collapsed at the Isle of Grain and huge waves began to sweep inland up the Thames and the Medway. All together over 1000 miles of coastlines were effected by this tidal surge (Ogley et al 2007).
The most notable recent floods occurred in 1968 when large areas of Kent and the Medway Valley flooded after a deluge of continuous rain. Ogley et al (2007) state that it started early on Sunday 15th September 1968 with just a few spots of rain, but this was soon to turn into a full scale disaster in the region. By Sunday afternoon the Medway and all its tributaries had failed against the weight of the water creating vast lakes. Cars were swept away and people were trapped in their houses. Ogley et al (2007) highlight that Tonbridge was by far the worst hit area and by midnight on the Sunday a wall of water 5ft high surged into Tonbridge High Street. All telephone lines were out, water supply pipes were washed away and gas and electric compromised. Due to the onslaught, the Cannon Lane bridge eventually collapsed into the Medway. Maidstone was also badly affected by the water and the town was declared closed by Sunday evening, however the high tide at 9pm brought no further chaos.
This incident in 1968 was the basis for the construction of the Leigh Barrier. In order to obtain the power to construct such a defense mechanism, the River Medway (Flood Relief) Act 1976 was passed. Using natural flood plains to aid defence, in 1981 the Leigh Barrier, Europe's largest on-line storage reservoir, was completed. The E.A state that this has successfully averted at least two incidences of flooding on the Medway every year over the last two decades.
The flood barrier was put to a test in October 2000 when the flow of the water exceeded that recorded in the 1968 floods. Without the barrier and the delicate knowledge of how much water to safely allow through, Tonbridge would have been devastated.
Ogley. B, Currie. I and M. Davidson (2007) 'The Kent Weather Book' (Froglets Publication).
Information on the Leigh Barrier has been extracted from the Environment Agency publication 'The Leigh Barrier: The Silent Saviour'. For more information on the Leigh Barrier including its history and operation, see the Environment Agency link to their publication above right.