British Waterways’ Reservoir Watch

Water is a valuable resource and it’s important that we make the most of what we have. By monitoring the levels in our reservoirs we can plan for the future and minimise disruption to the canals in times of drought.

British Waterways monitors the water levels in every one of its reservoirs on a weekly basis. Each reservoir has gauge boards, which are read by waterway operatives and then entered into our central database. The water level is converted into a reservoir holding, which can tell us how full the reservoir is (in percentage terms).

Adam Comerford, group hydrology manager at British Waterways explains: “By monitoring on the same day every week, throughout the year, we can calculate the change from one week to the next, and this helps us to understand how much water has gone into or out of a reservoir. We use the reservoir holding information to manage our water resources, deciding which reservoir(s) to use to feed the canal at different periods in the boating season and whether to use alternative resources, such as pumps, to supplement the reservoir water.

“Our records show reservoir levels for every week going back over many years, so we can compare the current situation against historical years, including drought periods.”

Reservoir Watch in May

In very sharp contrast to the month of March (which was exceptionally warm and recorded the lowest rainfall since 1953) and the previous couple of year (which exhibited significant rainfall deficiencies across much of the Midlands and South East) the month of April was remarkable for the very heavy rainfall observed. April was the coldest since 1989 and the wettest for over 100 years, leading to significant river flows and flooding in some catchments. For April, some locations witnessed around 300% of Long Term Average rainfall. It is important to note that whilst the April rainfall has certainly helped reduce rainfall deficiencies that had accumulated over the preceding 25 months, for the Midland region, the 2010-12 rainfall (April-April) is still the second lowest in the last 112 years at least. Although April was very wet, the prolonged period of low rainfall beforehand has left groundwater levels in many areas well below normal for this time of year, which could have an adverse effect on river flows if the dry conditions return.

Copy and paste the links below into your browser to view rainfall anomalies graphs and maps published by the Met Office for the month of May.

www.metoffice.gov.uk/climate/uk/anomalygraphs/2012/2012_Rainfall_Anomaly_1971-2000.gif
www.metoffice.gov.uk/climate/uk/anomacts/2012/4/2012_4_Rainfall_Anomaly_1971-2000.gif

Reservoir Holdings

The exceptional rainfall in April has provided much needed refill of a number of BW reservoir groups that had previously been a cause of concern. The Oxford & Grand Union group recovered by 30.6% over the month (partly due to the pumped reservoir refill via the Drought Schemes implemented by BW over the period, but also from the heavy rainfall). The GU North (Saddington Reservoir) increased in holding by a massive 51.8% over the month, to reach full. The Grand Union South Group has shown encouraging refill, but is still only just above the lowest historically low (for the period covered by this report) for this time of year.

Restrictions to lock use

The improved water resources position, which reflects the recent rainfall and reservoir refill, plus the successful results of a number of the Drought Schemes over the past few months, have meant that the GU Canal Leicester section was able to be reopened to navigation on Friday 11th May, and previously restricted lock opening times were extended at a number of other locations on the Grand Union and Oxford Canals. Maps detailing of the current restrictions can be found below.

BW will continue to closely monitor the reservoir holdings over the coming weeks as the main boating season progresses, and further updates to the drought restrictions maps will be published after the Diamond Jubilee Bank Holiday in June.

It is recommended that customers sign up to receive email alerts about restrictions

View a map showing the national risk of drought Updated 10/05/2012

View a map showing the regional risk of drought Updated 10/05/2012

Reservoir holdings for May 2012

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Reservoir holdings for April 2012

Reservoir holdings for March 2012

Reservoir holdings for February 2012

Reservoir holdings for January 2012

Reservoir holdings for December

Reservoir Watch in November

Reservoir Watch in October

Reservoir Watch in September

Reservoir Watch in August

Reservoir Watch in July

Reservoir Watch in June

Reservoir Watch in May

Reservoir Watch in April

Reservoir Watch in March

Last updated: 16/05/2012