Wendover Springs

NRFA Gauging Station: 39147. NGR: SP869093

Wendover Springs is thought to be the earliest extant stream flow monitoring site in the UK. Contemporary spring outflows are measured by the Canal and River Trust. The utility of these flow data is greatly enhanced by the existence of an 1841-97 dataset for the Wendover Arm of the then Grand Junction Canal (which was fed by the Springs). This early data provides a unique insight into hydrological variability in Victorian times. The data from Wendover Springs represents the first series to be released via the NRFA Long Records Initiative.

The NRFA gauging station pages for Wendover Springs can be found here.


Contemporary outflows from the springs are measured at a thin-plate weir (commissioned in 1962) maintained by the Canal and River Trust. This is by Wharf Road, Wendover at the head of the now disused Wendover Arm of the Grand Union Canal (originally the Grand Junction Canal, GJC). Research continues to discover precise details of the spring flow gauging methods used prior to 1962.

The Wendover Arm was constructed in the 1790s and, in addition to the navigation, was used to convey water to the Tring Summit, where the main line of the GJC crossed the Chiltern watershed. Records of monthly flows are currently available for the 1841-97 period. Earlier flow figures may well exist but have yet to be located. However, the Canal and River Trust hold microfiche copies of water levels for the 1963-1985 period and daily flows are held on the National River Flow Archive from 1963. It is hoped that continuing research - in co-operation with the Canal and River Trust will reveal further flow data to infill and extend the time series.

The Wendover Arm was constructed largely in the Chalk and leakage through the bed was a recurring problem, eventually leading to the closure of the Arm beyond the pumping station at Tringford in 1898. Since the closure of the Arm for navigation, water from the springs has continued to supply the Tring Summit - conveyed partly by open channel and partly by pipeline.

The catchment draining to the Wendover Springs is on the scarp of the Chilterns between Wendover Woods and Bascombe Hill. Topographically, the catchment is approximately 10-12 km 2 but the true contributing area is probably significantly greater. The highest point in the catchment is 250 m and the scarp is forested. Prior to the 1950s, the catchment was very rural but some subsequent urbanisation has taken place - mostly close to the springs themselves. Abstractions from the Chalk are not thought to have significantly affected the pre-1880 flow from the Wendover Springs but thereafter increased groundwater pumping for Halton House, and for public water supply, may have had some influence.


Period of record: 1841-1897; 1963-date

Monthly mean flows (daily flows from 1963). The original data were registered conventionally as ‘lockages’ - a canal operator’s unit, nominally 56,000 gallons (from the volume of a navigation lock) - but the precise method used to measure flows remains uncertain.

Contact the NRFA for access to the time series data for Wendover Springs.


Data transcribed from a manuscript archive of historical flow records collated by the Thames region of the, then, National Rivers Authority (now the Environment Agency) - the Wendover Springs data are copies of datasheets taken from an original Canal and River Trust ledger.

Comment on Data Series

Notwithstanding the lack of precise details concerning the method of flow measurement used, the monthly flow series for Wendover Springs captures the main characteristics of hydrological variability in central England during the middle of the nineteenth century. Comparisons of the pre-1885 flows with corresponding rainfall figures - for example those for Oxford - are generally encouraging - the droughts of the 1850s and the wet phase in 1877-82 being common features. However, runoff over the period prior to the closure of the Wendover Arm appears unrealistically low. This was certainly a period of below average rainfall but further research is needed to clarify the likely magnitude of artificial influences on the flow patterns at this time. The unique value of the Wendover Spring flow series was underlined during the remarkably wet autumn and winter of 2000/01. At Wendover, monthly flows remained above previous maxima from February to June 2001. The margin by which runoff over this period exceeded other protracted high flow events during the nineteenth century was a key piece of evidence in establishing the outstanding nature of the 2000/01 flow patterns within the context of the entire instrumented era across much of southern Britain.


Corrie, E. 1995. Restoration Report - Wendover Arm. Waterways World, June 1995 pp 44-46.

Dunwoody, R.B. 1911. Reports on the water supply of canal routes. Vol X Water Supply Committee of the Royal Commission appointed to enquire into and to report on the canals and inland navigations of the UK HMSO 1911 MAP showing gauges on Wendover Arm.

The Wendover Branch of the Grand Union Canal. Railway & Canal Historical Society Journal April 1967 Vol. XIII pp 21-26.

Baldwin Latham. 1885. Graph of volume of surface and underground water of various wells, 1816-1885 from: Discussion of committee of decrease of Water Supply. Quart.J.Roy.Met.Soc. Vol.XI Pt.1 1885 pgs.216-223 Plate 5.

Faulkner, A.H. 1993. The Grand Junction Canal. W.H. Walker & Brothers Ltd Rickmansworth.

Richardson, A. Water Supplies to the Tring Summit. Journal of the Railway & Canal Historical Society Pt 1 April 1969