April was a cool and wet month, with some unsettled weather and a very wintry spell in the final week. Occasional periods of heavy rainfall triggered localised surface water flooding and modest river flow spates.
More details are given in the latest monthly hydrological summary for the UK, the most authoritative analysis of water resources status in the country. The monthly summaries are produced by the National Hydrological Monitoring Programme, operated by the Centre for Ecology & Hydrology in conjunction with the British Geological Survey.
In April all regions of the UK were colder than average, and nationally the monthly temperature was 0.9°C below the long-term average (although not exceptional; 2012 and 2013 were colder).
It was also wetter than average in most regions, although not significantly so except in some isolated areas, while in south-west Britain it was relatively dry. The snowfall in the final week was unusually widespread for late April. In northern Britain some seasonally significant accumulations occurred even at low altitudes.
Summary author Jamie Hannaford of the Centre for Ecology & Hydrology said, “With overall river flows for April largely in the normal range or moderately above, and reservoir levels just above average at the national scale, the water resources outlook for the remainder of spring and summer 2016 is healthy.”
Groundwater levels receded at the majority of sites during the month, but remained in the normal range or slightly above, except in northern England and southern Scotland where exceptional levels persisted following the wet winter.
Reservoir levels were above 90% of capacity in all but a few northern impoundments, where they were only slightly below.
A PDF of the full 12-page April 2016 summary can be downloaded here.
The monthly summary is a look back at hydrological events occurring in April 2016. Latest information on flood warnings is provided by the Environment Agency, Natural Resources Wales and Scottish Environment Protection Agency.
The Centre for Ecology & Hydrology jointly operates the National Hydrological Monitoring Programme (for the UK) in conjunction with the British Geological Survey. NHMP scientists produce the UK Monthly Hydrological Summary which assesses rainfall, river flows, groundwater and reservoir levels. They also operate the UK’s National River Flow archive.
The NHMP also has a remit to analyse major flood and drought events in the UK and analyse long-term trends in UK hydrological data. The UK Monthly Hydrological Summary is normally published on, or before, the tenth working day, of the following month. A Hydrological Outlook for the UK is also available, and is updated monthly. The latest Outlook can be viewed here.