December was the 7th consecutive month of above average rainfall

dscn0417The Environment Agency water report for December shows it was the 7th consecutive month of above average rainfall for the South East Region. Flows and groundwater levels  continued to respond to rainfall on already saturated catchments. Most of the key sites are now at notably high levels or higher for the time of year and sixty eight flood warnings were issued.
The trend of wet months has continued, with December being the 7 th consecutive month with above average rainfall. The Region received 178% of the long term average rainfall for December, with the south of the Region wetter than the north. Total rainfall from the 19 th to the end of the month comprised about 70% of the monthly totals. There was widespread rainfall across the Region on the 19 th of December, with totals in excess of 40mm being recorded at a number of sites extending from East Hampshire Chalk to East Sussex Chalk and about 25mm being recorded on the Chilterns and Lee Chalk. The drought from October 2010 was broken by widespread rainfall from April onwards, with the Region and many catchments to the south and west having the wettest 9 months on record with up to 186% of the long term average for the period. 2012 has been the second wettest year on record for South East Region, with 2000 being the wettest. Cotswolds West and Thame catchments both had the wettest year on record.
Soil Moisture Deficit
Recharge and Groundwater Levels The soil moisture deficits remained zero during December, resulting in the Region continuing to be particularly responsive to any rainfall. The high rainfall totals and the saturated conditions resulted in an estimated two and a half times the average recharge during December. Groundwater levels have continued to rise at all the key indicator sites in response to the heavy rainfall and higher than average recharge. Five sites in the Chalk to the south and Jackaments in the Cotswolds have exceptionally high levels and 4 sites have notably high levels. Houndean Bottom (East Sussex Chalk) and Chilgrove (West Sussex Chalk) had the highest levels on record for December. Jackaments (Cotswolds West) and Rockley (Berkshire Downs) recorded the second highest levels for December, after 2000.
River Flows
As would be expected with a saturated catchment, all the rivers responded to the rainfall, particularly after the 19 th of the month. Eleven of the indicator sites had exceptionally high flows for December and eight had notably high flows. The monthly average flows were the 2 nd highest on record for seven of the rivers after December 2000. The peak daily flow for the River Coln at Bibury on the 25 th December was the highest on record. The River Kennet at Theale and the River Ver at Colney Street had above normal flows during December.
Reservoir Storage/Water Resource Zone Stocks
Reservoir storage was above or close to average for the time of year, with many of the online reservoirs close to capacity. Farmoor is the exception to this as abstraction was restricted by the water company owing to issues with high sediment in the Thames.
Full report
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