The Hydrological data UK series of publications documents and interprets hydrological conditions and water resource variability throughout the UK. Yearbooks are a major component in the series, bringing together the principal datasets relating to river flows, groundwater levels and areal rainfall for the UK. Beginning with the 1996 edition, the Yearbooks are now published in electronic form - providing access to a substantially greater volume of basic hydrological information and hydrometric data than could be included in any of the earlier Yearbooks (or their precursor publications).
A provisional Hydrological Review of the year is normally published (on the World Wide Web) in February of the following year. It is based largely on the material featured in the monthly Hydrological Summaries of Great Britain. This initial review is extended and revised as more hydrological information has become available; July is the target date for posting validated river flow and groundwater level data for the featured year.
A series of companion publications to the individual Yearbooks - the `Hydrometric Register and Statistics' volumes - provides a comprehensive reference source for hydrometric information which does not change materially from year to year; the third edition, covering the period 1991-95, was published in 1998 and may be purchased from the Institute of Hydrology.
Publications in the Hydrological data UK series rely on the active cooperation of
many organisations and individuals involved in the acquisition, processing and validation
of hydrometric data - a full list of data suppliers is given in the Directory of
Measuring Authorities. Ensuring the continuity and maintaining the quality of
hydrometric data is a major challenge at a time when there has never been a greater need
to maximise the integrity of the data upon which water management is based. The Natural
Environment Research Council (NERC) acknowledges and extends its appreciation to all who
have assisted in the collection of information for this publication.
The electronic Yearbooks incorporate all the major components featured in the recent
paper-based editions published in the Hydrological data UK series. The Hydrological Review
examines rainfall, evaporation, soil moisture, river flow and groundwater conditions
throughout the year. The River Flow and Groundwater Data sections provide daily flow data
and groundwater hydrographs for representative monitoring sites throughout the UK; for
comparison purposes a selection of reference statistics for the preceding record is also
given.
The Yearbook contents have been abstracted primarily from the National River Flow Archive
(NRFA) and National Groundwater Level Archive (NGLA). Responsibility for the initial
collection and processing of most river flow and groundwater level data rests with the
Environment Agency in England and Wales and the Scottish Environment Protection Agency in
Scotland. Following the 1989 Water Act, the Water Service PLCs assumed responsibility for
a small number of important monitoring sites for which historical - and a few contemporary
- datasets are held on the NRFA and NGLA. Until 1997 responsibility for the collection and
processing of river flow data in Northern Ireland was shared between the Departments of
Environment and Agriculture; operational responsibility resting with the Environment and
Heritage Service in the former, and the Rivers Agency in the latter. In 1998 the Rivers
Agency assumed sole responsibility for the collection and processing of river flow data in
Northern Ireland. Some groundwater level data continues to be provided by the Department
of the Environment(NI). Many of the above organisations also supplied valuable
material relating to significant hydrological events during 1997. Additional hydrometric
material has been provided by water supply companies, various research bodies and public
undertakings.
The regional rainfall figures featured in the Yearbook, and some of the material
incorporated in the Hydrological Review, have been provided by the Met
Office - latterly by their recently established National Climate Information Centre.
For historical comparisons of the rainfall over England and Wales, a dataset based upon
the homogeneous series derived by the Climatic Research Unit of the University of East
Anglia has been used.
Most of the rainfall data published in the Hydrological data UK series are in the form of
monthly rainfall totals for catchment areas. These areal figures are derived by the
Centre for Ecology and Hydrology (formerly the Institute of Hydrology). The Met Office,
which maintains the national archives
of rainfall and climatological data at its headquarters in Bracknell, can provide details
of the availability of daily and monthly rainfall data associated with individual
raingauges. The bulk of the evaporation and soil moisture information featured in the
Yearbook derives from MORECS (Meteorological Office Rainfall and Evapotranspiration
Calculation System). This is a weekly issue of maps and tables of rainfall,
evapotranspiration, soil moisture deficit, effective rainfall, and the meteorological
variables used to calculate them. The data are used to provide values for 40 km squares
and various sets of maps and tables are available according to customer requirements.
Enquiries concerning this service should be directed to: (01344) 856858. The Met Office
Web Site provides a range of free weather information and details of subscription
services. Available products include inland and international forecasts, pressure charts,
satellite images and weather reports from around the UK.
Publication of river flow data for Great Britain started with the series of Surface
Water Yearbooks. The first edition, which was published in 1938 for the water-year
(October-September) 1935-36, also included selected data for the previous fifteen years;
the edition for 1936-37 followed in 1939. Both these publications were prepared under the
direction of the Inland Water Survey Committee. Assisted by the Scottish Office, the
Committee continued to publish hydrological data after the Second World War; the Yearbook
for the period 1937-45 was published as a single volume in 1952. Due to economic
stringency, the Survey was suspended in 1952 for a period of two years but was then
re-formed as the Surface Water Survey Centre of Great Britain. A Yearbook covering the
years 1945-53 was published in 1955.
In 1964 the Survey was transferred to the Water Resources Board where it remained until
the Board was disbanded in 1974. The work of collecting and publishing surface water
information in England and Wales then passed to the newly created Water Data Unit of the
Department of the Environment (DoE). Yearbooks were published jointly each year by these
organisations and the Scottish Office for the water years 1953-54 to 1965-66; thereafter
information for the five calendar years 1966 to 1970 was published in one volume in 1974.
Subsequent editions were renamed `Surface Water: United Kingdom' to mark the inclusion of
the first records from Northern Ireland and in recognition of the move away from single
year volumes. Two volumes of Surface Water: United Kingdom, covering the years 1971-73 and
1974-76 were published jointly by the Water Data Unit, the Scottish Development Department
(now The Scottish Office Environment Department) and the Department of the Environment for
Northern Ireland.
Following the transfer of the Surface Water Archive to the NERC in 1982, the
final edition of Surface Water: United Kingdom, for the years 1977-80, was prepared by the
Institute of Hydrology at the request of the Water Directorate of the Department of the
Environment, and published in 1983. The 1981 and 1982 Yearbooks were prepared concurrently
and were, in 1985, the first Yearbooks published in the Hydrological data UK series.
Further Yearbooks - the editions for 1983 to 1995 - were published over the following 11
years. Responsibility for the publication of
data upon which assessments of water resources in England and Wales may be made, was
transferred (under the Water Act 1989) from the Department of the Environment (now the
Department of the Environment, Transport and the Regions - DETR) to the National Rivers
Authority (now the Environment Agency). Part of this responsibility continued to be discharged
through the publication of the Yearbook series. Water quality data - a selection from the Harmonised Monitoring Scheme Archive -
were published in each Yearbook from 1986 to 1995; responsibility for the maintenance of
the Harmonised Monitoring database was transferred from the DETR to the Environment Agency
in 1998.