Our Drought Plan. A guide for customers. Drought Plan

Transcription

1 Our Drought Plan A guide for customers Drought Plan 1

2 Contents 3 What is a Drought Plan? 4 What is a drought? 5 Why does a Drought Plan need updating? 6 Where does drinking water come from in our region? 8 Water resource zones 10 How do we monitor water resources? 11 How do we use this information to manage a drought? 12 What actions would we take in a drought? 13 What restrictions might we introduce during a drought? 2 Drought Plan

3 What is a Drought Plan? A Drought Plan sets out the actions we would expect to take in order to continue to provide essential supplies of water while protecting the environment. This guide summarises our Drought Plan. It sets out how and when we aim to: Control demand for water Take actions to increase water supplies Monitor the water that is available during a drought Communicate with customers about water shortages This guide is not a substitute for our full Drought Plan, which you can find on our website at droughtplan. We have prepared the full Plan according to guidelines devised by the Environment Agency. Drought Plan 3

4 What is a drought? A drought is a prolonged period of abnormally low rainfall. In south-east England, a drought that has the potential to affect water supplies to homes and businesses is often caused by an unusually dry winter followed by a dry summer. The worst have been brought about by two consecutive dry winters, followed by a dry summer. The reason why such weather patterns cause problems is explained below. Rainfall in winter percolates down into the ground and is stored naturally in layers of water-bearing rocks called aquifers. These aquifers feed the rivers and boreholes from which we take water. If there is not enough rainfall in winter then the aquifers are not refilled and so a drought can occur in the following summer. Water flow in rivers comes from two sources: water that has naturally flowed from aquifers, and surface run-off (rainfall that has not percolated into the ground). During periods of low rainfall, it is the flow of water from aquifers that maintains the flow in rivers. In the summer months, most rainfall simply evaporates or is taken up by plants, leaving very little available to recharge underground sources or contribute to river flows. Droughts affect different water users in different ways. For example, an agricultural drought can occur after just a few weeks of dry and sunny weather during the growing season. However, it takes at least several months of belowaverage rainfall to cause a drought that affects water resources, which in turn affects how much water we have available for customers. In a drought, restrictions on water use may be necessary. How long these restrictions are required for depends on the type of drought situation. Restrictions can be in place for a few months or a year or more. Droughts develop over a period of months. This allows time for water companies to advise customers, via the media and other communications, about the situation and about how to use water wisely. Reducing the amount of water customers use helps to delay the point when restrictions become necessary. 4 Drought Plan

5 Why does a Drought Plan need updating? All UK water companies must update their Drought Plans at least every three years. This version replaces the Plan published in November 2010 and includes changes reflecting: Revised legislation, which affects temporary use bans (formerly known as hosepipe bans) for household customers and non-essential water use for businesses Detailed comments made by the Environment Agency on the 2010 version Our assessment of the impact our actions in a drought might have on the environment (more details on this are included with the full version of our Drought Plan). In updating our Plan, we have also considered guidance from UK Water Industry Research, our own customer research and the need for a consistent approach with neighbouring water companies. Drought Plan 5

6 Where does drinking water come from in our region? In our region 80 per cent of drinking water supplies come from rivers. The remaining 20 per cent comes from boreholes which pump water from aquifers. In both cases, the water is treated to a high standard before it reaches your tap. After taking water from the rivers, we either store it in large reservoirs for later use or treat it and put it directly into supply. Reservoirs normally provide sufficient storage for us to maintain supplies during the summer months, when river flows are low. The amount of water we can take from rivers and boreholes is controlled by the Environment Agency. In some cases, when river flows are low, there is a point at which the Environment Agency has to restrict the amount water companies can take, to protect the environment by ensuring there is sufficient water left in the rivers. This strikes a balance between preserving supplies for the public and protecting the environment. 6 Drought Plan

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8 Water resource zones We supply a large part of south-east England, between Cirencester in the west and Dartford in the east and between Banbury in the north and Guildford in the south, although other water companies provide the supply in some parts of this area. We divide the area we supply into water resource zones. These are defined by the major towns or cities, the main points where we pump water from rivers or from boreholes, and the major water mains. There are six water resource zones in our region: London; Swindon and Oxfordshire; Kennet Valley; Guildford; Slough, Wycombe and Aylesbury; and Henley. We are able to move water around within these zones to a certain extent, but we don t generally transfer water in large volumes outside them. A drought can affect the zones in different ways depending on where the water for each zone comes from. This is why, during a drought, one zone may have different usage restrictions to another. London water resource zone London is by far our largest water resource zone in population terms. Water for the capital is mainly pumped from the River Thames and the River Lee and stored in reservoirs. The reservoirs allow us to store water in the winter when there is plenty of flow in the rivers and use it during the summer when river flows are low. The remainder (roughly ten per cent) comes from boreholes. The amount of water we can take out of the River Thames is restricted when flows are low. There are two groups of reservoirs one in south-west London and another in the Lee Valley. Water Resource Zones outside London In order of decreasing size, the five zones outside London are as follows: Swindon and Oxfordshire We have a major reservoir at Farmoor, near Oxford, which we fill from the River Thames. This provides just over half the supplies in the zone. We also have a small reservoir at Grimsbury, near Banbury, filled from the River Cherwell, while the rest comes from groundwater sources, including some in the upper Kennet Valley. As with London, the amount we take is restricted if the flow in the Thames drops below a set level. Kennet Valley (including Reading and Newbury) Some water is pumped direct from the River Kennet to treatment works, while other supplies are from boreholes. Guildford Some water is pumped direct from the River Wey to treatment works, while other supplies are from boreholes. Slough, Wycombe and Aylesbury All water comes from boreholes. Henley All water comes from boreholes. 8 Drought Plan

9 Swindon and Oxfordshire Slough, Wycombe and Aylesbury Banbury Henley Luton Stevenage Bishop s Stortford Cirencester Swindon Oxford High Wycombe Slough Waltham Cross Wembley LONDON Dartford Newbury Reading Croydon Basingstoke Guildford Kennet Valley (including Reading and Newbury) Crawley London Guildford Drought Plan 9

10 How do we monitor water resources? Our regular monitoring of water levels in our region enables us to tell when a drought is likely to develop and once it has begun how severe it could become. The following measurements are all important in identifying a potential drought: We analyse the Environment Agency s rainfall records to recognise when significant deficits are building up. It is also vital we measure groundwater levels in the aquifers that supply local boreholes. Groundwater levels are a key indicator of the onset of a drought - the lower the level, the worse the drought. The Environment Agency regularly monitors groundwater levels at a range of observation boreholes. This is particularly important outside London, where most supplies are from boreholes (see above). As mentioned in the previous point, river flows depend on baseflow from aquifers and are supplemented by recent rainfall. The Environment Agency measures flows at a number of gauging points. The amount of water stored in reservoirs is also a critical measurement which we monitor regularly. As an example of the type of rainfall pattern that can cause a drought, this chart shows total rainfall at 12 measuring stations across our region in 1975 and In each case, the bar shows the percentage difference from the 128-year long-term average rainfall figure for the area. 80 mm of rainfall above or below avergae for the month Apr May Jun 75 Jul 75 Aug Sep Oct Nov 75 Dec 75 Jan 76 Feb 76 Mar 76 Apr 76 May 76 Jun 76 Jul 76 Dec Nov 76 Oct Aug 76 Sep 76 Month / year 10 Drought Plan

11 How do we use this information to manage a drought? As a drought develops, river flows, groundwater levels and the amount of water stored in reservoirs falls below the normal levels for the time of year. We measure the levels and use mathematical models to assess the current and potential risk to water supplies. We use these calculations to forecast the likely availability of water under a range of scenarios covering different patterns of rainfall and water usage. This helps us decide on the right balance of actions in a drought. During a drought, we follow a series of protocols for each zone these are decision-making steps which decide the actions we should take. They depend on the time of year, groundwater levels, river flows and how much water is stored in reservoirs. We use these levels to predict how the drought could worsen. In a drought we consider a range of measures that might affect the supply of, and demand for, water. It is very important to let customers know early enough about how they can use water more wisely to gain maximum water savings. This allows us more time to prepare for and be granted the next level of measures, should they be needed. For example a Drought Order will normally only be granted several weeks after a temporary use ban has been put in place. Drought Plan 11

12 What actions would we take in a drought? Measures to provide extra supply include using water sources that are only permitted for use in a drought, while demand measures are designed to reduce the amount of water used by us and our customers. The extent to which we implement these steps depends on the severity of the drought. We aim to make efficient use of water as part of our normal dayto-day operations. For example, we make intensive efforts to hit our annual leakage reduction target, even during severe winter weather, when plunging temperatures cause burst pipes. We also encourage our customers to use water wisely, providing a range of free water-saving devices and giving advice on how to conserve supplies. In addition, we install free water meters, which encourage people to use water sparingly and help reduce their bills. We would anticipate stepping up these activities still further during a drought with the exception of installing meters, where extending our existing programme is unlikely to achieve immediate water savings. In a drought, we would expect to consider the following measures: Make the most efficient use of existing water sources by using those that are more resistant to drought in preference to other sources. For example, in London and the Swindon and Oxfordshire water resource zones, we might use more groundwater, to conserve the water stored in reservoirs. Introduce one or more of a range of schemes developed for use in the event of a drought. For example, we would use the Thames Gateway Water Treatment Works, in east London. This desalination plant allows us to take water from the tidal part of the Thames and remove the salt to produce drinking water. In London our North London Artificial Recharge Scheme allows us to store surplus winter supplies in the deep chalk aquifer beneath the capital so that we can put it back into supply during drought periods. Apply to the Environment Agency for the granting of drought permits, allowing us to take more water from certain sources. To do so, they must be satisfied that we have taken all other necessary measures to restrict demand and have assessed the impact on the environment, taking steps to reduce any adverse environmental effects where appropriate. In the unlikely event that we need to consider stricter measures, a range of more extreme options, in a very severe drought, would include transporting water by tanker, and using alternative sources for non-drinking water. 12 Drought Plan

13 What restrictions might we introduce during a drought? Droughts vary in severity. Like all water companies, we have used past records to define various levels of water usage restrictions, which increase with the seriousness of the drought. We have agreed with Ofwat the organisation which decides the level of customers bills and the Consumer Council for Water (the consumer champion) four escalating levels. These determine how often and to what extent customers should expect restrictions on their water usage. These are sometimes called our agreed levels of service. This means that customers should expect us to restrict their usage only very rarely, when a lack of rainfall leaves no other choice. Since we published our last Drought Plan, the Government has updated the legislation relating to droughts. The Drought Direction 2011 gives water companies more powers than they previously had, using hosepipe bans, to implement restrictions. The old hosepipe ban powers have been replaced by new temporary use ban powers. Level 1 Once every five years on average, the drought severity is such that we expect to have to warn customers formally that water resources are lower than normal and ask them to use water sparingly. We would typically do this via TV, radio, newspapers, the internet and social media. At this level, no restrictions should be needed but we would warn our customers that they may be required later on if the situation continued to worsen. Level 2 Once in every ten years on average, we anticipate a moderately serious drought that would require us to introduce a temporary use ban forbidding the use of sprinklers and unattended hosepipes. This would be accompanied by stepping up the level of communications mentioned above perhaps, for example, by advertising more frequently. Drought Plan 13

14 Level 3 Severe droughts are anticipated on average once in 20 years. In these circumstances, we would also expect to impose further restrictions on water use. We can do so under the temporary use ban or apply to the Secretary of State for a Drought Order to ban nonessential use. An extension of the temporary use ban would not require permission from the Government and we would give a three-week notice period. During this time, anyone can make representations to us giving their view on the proposed restrictions, whether positive or negative. We will then say how we have taken these into account in deciding exactly which uses to restrict. A temporary use ban could restrict the following uses: Watering a garden using a hosepipe (See note below) Cleaning a private motor vehicle using a hosepipe Watering plants on domestic or other noncommercial premises using a hosepipe Cleaning a private leisure boat using a hosepipe Filling or maintaining a domestic swimming or paddling pool Drawing water, using a hosepipe, for domestic recreational use Filling or maintaining a domestic pond using a hosepipe Filling or maintaining an ornamental fountain Cleaning walls or windows of domestic premises using a hosepipe Cleaning paths or patios using a hosepipe Cleaning other artificial outdoor surfaces using a hosepipe Note: A change of legislation in 2011 widened the definition of a garden to include a park, gardens open to the public, a lawn, a grass verge, an area of grass used for sport or recreation, an allotment garden, any area of an allotment used for non-commercial purposes, and any other green space. However, it does not include agricultural land, or various other areas which are listed in the full version of this Drought Plan. We would expect to ban all 11 activities simultaneously to help maximise water savings and send out a strong and simple message that the situation is worsening. We propose making two exemptions: one for small businesses whose activity and viability would be unduly affected typically, window cleaners and companies that wash vehicles using a hosepipe and the other for people who are disabled. We can make these exemptions for the whole duration of the drought or can remove them if the drought gets worse. We propose that only the exemption for people who are disabled would run throughout the drought. We propose removing the exemption for small businesses if and when we impose the next level of restrictions: a ban on non-essential water use for commercial activities. To do this we would need to apply to the Government for an Ordinary Drought Order. This would allow us to ban the following activities: Watering outdoor plants on commercial premises Filling or maintaining a non-domestic swimming or paddling pool Filling or maintaining a pond Operating a mechanical vehicle washer Cleaning any vehicle, boat, aircraft or railway rolling stock Cleaning non-domestic premises Cleaning a window of a non-domestic building Cleaning industrial plant Suppressing dust Operating cisterns As with a temporary use ban, we would intend to introduce all restrictions together. In this case there are ten activities that could be restricted. We propose notifying people at least ten weeks before we need to impose a Drought Order. Again, individuals and organisations can make representations to us stating their view of the effect of restrictions and, with a Drought Order, there is the provision for a public hearing to determine whether the Order should be granted. As part of this process, we would also need to submit to the Government a statement of reasons explaining why and how the exceptional shortage of rainfall was likely to seriously affect water supplies. In this more serious stage of Level 3, we would also be likely to apply to the Environment Agency for drought permits to allow us to take more water from certain sources. 14 Drought Plan

15 Level 4 We plan never to reach this level of severity, which would involve a drought worse than any since records began in River flows would be exceedingly low and reservoir storage levels severely below their normal level, with approximately only 30 days of supply remaining. It would require extreme measures to reduce water usage, such as rota cuts, when water usage is restricted at certain periods of time, and standpipes. This would require further permission from the Government and would require an Emergency Drought Order which allows companies to implement more severe measures than under an Ordinary Drought Order. This option would only be available once we had fully employed all possible water resources. How will we tell you what s going on? Good communications with our customers are more vital than ever in a drought. We need to keep everyone informed about its potential severity, tell customers what they can do to help and inform them of any likely restrictions we might put on water use. We will aim to start our drought communications campaign well before restrictions on water use need to be imposed. To communicate to as many people as possible, our messages will mainly be via the media newspapers, radio and TV and we will therefore aim to attract their attention with informative and up-to-date news releases. We will also use our website and social media to give regular updates on the drought situation and provide advice on saving water. If the drought continues, we may need to supplement this with advertising. A drought is unlikely to be limited to the Thames Water area, so we will work together with other water companies in the region to ensure consistent messages. Drought Plan 15

16 Final Drought Plan Following public consultation on our draft Drought Plan (14 December February 2012), we produced a revised draft Drought Plan taking into account, where appropriate, the comments received. Defra reviewed our revised Plan and required us to make additional changes to reflect experienced gained during the drought of 2012, and to ensure the information included in our Drought Permit option reports was comprehensive. We then undertook further limited consultation on the revised Plan. Defra has confirmed that our Plan meets its requirements and has instructed us to publish it as our Final Drought Plan, together with the supporting documents. The Final Drought Plan is available to download on our website at /13