Flood on the River Thames Flood on the River Thames

River Pang at Bucklebury River Pang at Bucklebury

Water Watch

The data holdings of the National River Flow Archive and National Groundwater Level Archive – together with the ability to analyse and interpret them – provide a capability to report regularly on hydrological conditions throughout the UK. Wide dissemination of such information helps to increase public understanding of hydrological and water resources issues. Through time, consistent monitoring also allows hydrological trends to be identified and their implications assessed.

Water Watch is a component of the National Hydrological Monitoring Programme (NHMP) which was started in 1988 and is undertaken jointly by the Centre for Ecology & Hydrology and the British Geological Survey. The programme relies on the active co-operation of measuring authorities throughout the UK (see below).

Click below to access standard monthly and annual reports issued as part of the NHMP. The data featured in the monthly Hydrological Summaries are provisional and may be subject to significant revision: this applies particularly to data collected during flood and drought conditions.

Reports on recent hydrological events of major significance are also available. The most recently published are listed below:

Financial support for the production of the Monthly Hydrological Summaries of the UK is provided by the Department of Environment, Food and Rural Affairs (Defra), the Environment Agency (England & Wales), the Scottish Environment Protection Agency (SEPA), the Rivers Agency (Northern Ireland), and the Office of Water Services.

For the distribution of monitoring sites used in the National Hydrological Monitoring Programme see the Location Map.

Data Sources

River flow and groundwater level data are provided by the regional divisions of the Environment Agency in England, the Environment Agency Wales, the Scottish Environment Protection Agency, the Rivers Agency and the Northern Ireland Environment Agency. Details of reservoir stocks are provided by the Water Service Companies, the Environment Agency, Scottish Water and Northern Ireland Water.

Most rainfall data are provided by the Met Office National Climate Information Centre (NCIC). To allow better spatial differentiation, most regional rainfall figures for Britain are presented for the regional divisions of the precursor organisations of the Environment Agency and SEPA.

For historical comparisons of national and regional rainfall totals the NCIC monthly series are normally used but for England and Wales the homogenised E&W rainfall series developed by the Climatic Research Unit (University of East Anglia) and currently updated by the Hadley Centre may be used.