|The drier than average winter of 2016-17 for the Thames Area has resulted in below normal rainfall at only 92% of the 1981-2010 average. The result is below normal groundwater levels and river flows being recorded across the South Chilterns Catchment.
|In the case of the River Pang the groundwater levels in the catchment have been lower than average for the previous seven months. The River Pang is a winterbourne river; that means it relies on groundwater levels being above the bed of the river channel for the river to flow. As seasonal changes occur in groundwater levels (declining during the summer, and rising during the late winter) the source of the river will move up and down the river course. This year (2017) groundwater levels did not recover as much as would be expected during the winter which has meant that the source of the River Pang has moved further downstream than in a ‘normal’ year. This year the upper reaches of the river (upstream of Hampstead Norreys) have been dry since July with this dry section moving down to Bucklebury in October. The last time this occurred was the autumn of 2011 following a similarly dry previous winter period. For live data see the Pang Dashboard.
Compare with 2014 floods.
|© George Edwards 04/10/17|