Water Resources in SE England
Increasing pressure on water resources from climate change and population growth mean that we all need to use water more wisely. Waterwise is an independent not-for-profit organisation established in 2005 with the vision that water will be used wisely, every day, everywhere.
Evidence from the 2012 drought suggests that we need to support a better level of awareness of water resources amongst the general public. This website pulls together the water resources update published monthly by the water companies in the South East of England. As an action from the Waterwise Water Efficiency Strategy for the UK we proposed setting up a water situation report portal. This website provides a research test portal for water companies in the South East of England - Affinity Water, Portsmouth Water, Thames Water, South East Water, Southern Water and SES Water.
We are interested to hear back from water customers but also those from a design and engagement background on:
- Is this the right level of information for you to understand the current water resources situation?
- Which graphics are the easiest to understand?
- Is it helpful to see the water resources situation for the region rather than just your water company?
- Would daily information be more useful?
- Would it help to see how supply and demand are faring in relation to targets set by water companies?
- Would you like to see this information in newspapers or on TV weather reports?
On 30th June, the Thames Regional Soil Moisture Deficit (SMD) total was 92mm which is higher (i.e. drier) than expected for the time of year.
At the end of June, groundwater levels were generally Normal, with some exceptions. An area of the Lee Chalk in North East London and an area of the Guildford Lower Greensands were Below Normal, whereas an area of the Cotswolds and an area of Marlborough Downs were Above Normal.
Generally, river flows were at their long term averages in June. The Teddington Target Flow was maintained at 800 megalitres/day during June in agreement with the Environment Agency. Although since 06 July 2018 the Teddington
Target Flow has changed to 700 megalitres/day in agreement with the Environment Agency.
Reservoir storage on the 30th June 2018 for London as a whole was 93% (Thames Valley 96% & Lee Valley 87%) and Farmoor storage was 95%.
Portsmouth Water has no large raw water storage reservoirs. It relies almost entirely upon groundwater reserves in the chalk aquifers of the South Downs and abstracts its raw water from wells, boreholes and springs. It has one river abstraction at Gaters Mill on the River Itchen, a chalk river with a groundwater baseflow.
Those reserves rise and fall with the seasons and so Portsmouth Water pays particular attention to the local hydrogeological data by monitoring rainfall at its Havant Offices, groundwater levels in the chalk at Idsworth on the Hampshire/Sussex border, as well as the total yield from the natural springs at Havant and Bedhampton.
These resources are monitored on a daily basis and reported upon on a monthly basis. The information here is therefore at times one month behind the most current situation.
The information gathered is reproduced here for information purposes; no guarantee is given as to its accuracy.
Rainfall at Havant
The Rainfall Records at the Company’s Head Office at Havant date back to 1886.
The month of June saw little or no rainfall, with the maximum daily rainfall only 0.4mm on Wednesday 13 June 2018.
Total rainfall for the month was 0.5mm, much lower than the 30 year long term average of 49mm.
Groundwater Levels at Idsworth
The Company has groundwater records from the Idsworth Estate Well, north of Rowlands Castle, which date back to 1931. Water levels in the Well, which is entirely unaffected by abstraction, give an accurate indication of the groundwater reserves of the South Downs. In the winter, levels usually rise in response to rainfall, whilst during the summer, levels recede as any summer rainfall either evaporates or is taken up by trees and plants before reaching the aquifer below. Levels can fluctuate by as much as 20m.
The Groundwater level is usually recorded in metres AOD (Above Ordnance Datum), Ordnance Datum principally being equivalent to sea level.
Despite the dry winter of 2016/17, ground water remained within the “normal” levels for the spring of 2017. During the summer, levels fell to a “low” level, but recovered to “normal” levels by the end of August 2017.
It is normal to see ground water levels recover in the autumn as rainfall increases. Cumulative rainfall between September 2017 and June 2018 was approximately 90% of the long term average. Rainfall was low in June but was balanced with higher than average rainfall in April and May. As is normal for this time of year, ground water has fallen from a maximum recovery level of 26.7m in May to approximately 3.1 above the long term average at the end of June.
Despite the low rainfall in June, if rainfall remains close to average for the spring and summer, we do not see the need for drought control measures for the summer of 2018, such as temporary use bans. We would encourage all customers to continue to use water wisely.
The graph below shows the change in groundwater level over the last twenty four months compared to the Long Term Average (last 30 years).
CEH Drought Portal
The UK drought portal is a tool to help visualise the current meteorological conditions across the UK, and understand the severity and magnitude of drought at different spatial scales across the UK over the past half century. Droughts can be visualised and explored through interactive maps and graphs. Data is updated at the beginning of each month.
Click here to access the tool.
The December 2017 hydrological situation update by CEH is available here.