From 1-30 November, rainfall across the Thames catchment was 115% of the 134 year historic monthly average, with 87.3mm.
Rainfall in the last year
The graph below shows the rainfall over the last year and percentage increase and decrease against the monthly average.
Where our water comes from
Across our region, we take about 65 per cent of our source water from rivers, in a process called abstraction. We then store this in large, open reservoirs (known as surface reservoirs) before putting it through our treatment process to turn it into drinking water.
The remaining 35 per cent comes from natural underground reservoirs called aquifers, from which we pump water using boreholes. This water has originally fallen as rain and sunk down into the ground in a process called recharge. These supplies from aquifers are referred to as groundwater.
Reservoir and water levels
The diagram below shows the rainfall and levels of water in the rivers, aquifers and reservoirs in our area, for the last month.
Water situation summary
On 30th November, the Thames Regional Soil Moisture Deficit (SMD) total was 49 mm which is higher (i.e. drier) than expected for the time of year.
At the end of November, groundwater levels were generally below average.Generally, river flows were significantly below their long term averages in November. The Teddington Target Flow, which determines the minimum flow that must be maintained over Teddington weir, dropped to 400 Ml/d on 4th
November but has subsequently risen to 600 Ml/d.
Reservoir storage on the 30th November 2018 for London as a whole was 61% (West London 57% & Lee Valley 79%) and Farmoor storage was 94%.