March 2014


Period: From March 2014      Issued on 12.03.2014 using data to the end of February

Summary

February was another exceptionally wet month, bringing to a close the wettest winter on record for much of the UK. Consequently, river flows and groundwater levels were exceptionally high in February, with flooding causing damage and disruption early in the month. The end of February and early March has seen some respite in the weather, but river flows and groundwater levels are likely to remain above average in March across much of the UK,  and exceptionally so in southern and central areas, as a consequence of the amount of water stored in catchments and aquifers following the wet winter. The outlook for spring (March – May) is also suggestive of higher-than-normal river flows and groundwater levels, in southern England especially where there remains an elevated risk .of flooding. The water resources outlook for spring and summer 2014 is very favourable.

Rainfall

Latest predictions for UK precipitation suggest a near-climatological risk of above-average rainfall in March. Similarly, for March-April-May as a whole the risk of either above- or below-average rainfall remains near climatological levels. The probability that UK precipitation for March-April-May will fall into the driest of five of equal classes is 15% and the probability that it will fall into the wettest  of five equal classes is between 15% and 20% (the 1981-2010 probability for each of these categories is 20%).

River flows

February river flows were substantially above average across the UK, with the exception of the far northwest of Scotland, and were exceptionally high (with a number of new records established) across southern England, Northern Ireland and parts of southern and eastern Scotland. The one-month outlook is suggestive of normal to above-normal river flows across much of the UK, with above normal flows most likely in central England, parts of Wales and some areas in Scotland, and notably or exceptionally high flows likely in parts of southern England. The three-month ahead outlook suggests a return towards normal conditions across much of the UK, but there is a high likelihood that river flows will remain above-normal through the spring particularly in southern England, because of the exceptional amount of water stored in soils and aquifers.

Groundwater

February groundwater levels were exceptionally high across the Chalk of southern England and in the most westerly outcrops of the Permo-Triassic sandstones, with new February records established in several boreholes in these areas. Elsewhere, generally levels were notably high, with the exception of parts of East Anglia and Yorkshire where levels were normal or below. The one month outlook suggests a continuation of these patterns; exceptional levels are very likely across the southern Chalk and in the Permo-Triassic of the northwest, with even modest rainfall amounts in March. The three month outlook suggests that levels will tend towards normal conditions across much of the Chalk, and below normal levels may persist in parts of eastern England. However, levels are still likely to remain above normal in the southern Chalk, with exceptional levels persisting into early summer in some parts of the aquifer, with an ongoing elevated risk of flooding in susceptible areas. Exceptionally high levels are also very likely to persist in the Permo-Triassic  aquifers of northwest England and southwest Scotland.  Elsewhere levels are likely in the normal range.