www.environment-agency.gov.uk Do we need large-scale water transfers for south east England? September 2006 Contents Summary 1 1. Introduction 3 2. What is a water grid? 3 3. New large-scale water transfers from other parts of England and Wales 5 3.1 Water Resources Board 1973 5 3.2 National Rivers Authority 1994 6 3.3 A new assessment of the cost of water transfers 7 3.4 The environmental impact of new water transfers 8 3.5 Is a water grid necessary? 9 4. Drought 10 5. Climate change 12 6. Future demand for water in south east England 13 7. Water companies’ 2004 plans 15 8. Other options 17 8.1 Demand management 17 8.1.1 Leakage reduction 17 8.1.2 Industrial and commercial water efficiency 17 8.1.3 Household water efficiency 18 8.2 Other resource development options 18 8.2.1 Desalination 18 8.2.2 Effluent re-use 19 8.2.3 Transfers of water from other countries 19 9. Conclusions 20 Summary In February 2006, Ministers asked the Environment Agency to review the need for such large-scale transfers of water to south east England. We reported our preliminary findings at the Secretary of State’s water meeting on 1 June 2006. This report provides our assessment of the need for large-scale water transfers to south east England. We conclude that there is no new evidence of a need for large-scale transfers of water to south east England from the north of England or from Wales. Water companies’ existing plans provide for water supply in south east England to 2025 without the need for large scale transfers. Such transfers are more expensive and environmentally damaging than the measures already in water companies’ water resources plans. The drought in south east England, while serious, is similar to the droughts of 1933-34 and 1975-76. Restrictions on water use in such droughts are part of water companies’ planned responses, in line with water resources legislation and Government policy. These restrictions are not in themselves evidence that supply is insufficient. Water companies already have plans to meet the demand for water in south east England for the next 25 years. We reviewed these in 2004 and there is no reason to believe that they have suddenly become inadequate. These plans include six new or extended reservoirs in south east England. It would be possible instead to build large pipelines to move water to south east England. The feasibility of such a scheme is not in question. It would be worth building a water grid only if: • The demand for water in south east England exceeds the available supply; and • There are no better, cheaper options locally. Water companies’ estimates of future water demand in south east England allow for two million more people and 8% more water use by each person by 2030. We commissioned consulting engineers to examine the cost of meeting this additional demand for water in south east England by constructing new reservoirs in the north of England and a pipeline to bring the water to London. The capital cost of this would be between £9 billion and £15 billion, or £8 million to £14 million per megalitre a day. In their 2004 plans, water companies estimated that the cost of building new reservoirs in south east England to meet the same demand is about £1.6 million per megalitre a day. The pipeline would cost at least four times as much as developing new resources in the south east. Similarly, the cost of developing and transferring water from Wales to London has been estimated at a minimum of £2.4 million per megalitre a day, with this figure assuming transfers through the river Severn. Using the river Severn as part of a transfer network could present significant environmental problems. These were last investigated by the National Rivers Authority in 1994. Our current view is that these environmental problems would be difficult and expensive to overcome. Environment Agency - Do we need large-scale water transfers for south east England? - 1 - In the longer term, beyond the 2020s, further water transfer may prove necessary. We are about to start work on our next water resources strategy for England and Wales. As part of this strategy we will review the need for further water transfers. Our view is that there is still considerable scope for further water efficiency in south east England. Water companies must reduce leakage and work with people and industry to make the best use of the water that is available. The drought reminds us that water is precious for people and the environment, and that we must all take responsibility for using it responsibly. Water companies across south east England have plans to develop new resources in the next decade. They must follow these plans so that there is no delay in the detailed investigation of the need for these proposed new schemes and reservoirs. At the same time, water companies must take all possible opportunities to manage demand. Water companies must keep all options under review as they prepare their next water resources plans. Draft plans are due in 2008 and we expect water companies to demonstrate that they have considered all of the possible options. These plans will undergo full public consultation and will provide an opportunity for people to debate the future of public water supply. Environment Agency - Do we need large-scale water transfers for south east England? - 2 - 1. Introduction This report is a preliminary assessment of the advantages, disadvantages and need for large-scale water transfers to south east England. It draws principally on existing published work, but also reports on a new assessment of the cost of developing new transfers of water. We review the case for a water grid by comparing it with the other options for meeting future demand in south east England. 2. What is a water grid? Many people imagine that a water grid would connect all the major reservoirs and boreholes, allowing water to be shared between all of them in a network similar to the national electricity grid. The existing water supply network is very far from this model. There are 24 water companies in England and Wales. Each supplies water to a defined geographical area. The 24 water companies operate more than a hundred separate resource zones (figure 1). A resource zone is the largest area in which all customers face an equal risk to supply. Supply network constraints usually mean that water from a particular source can reach only part of the zone, so even resource zones are rarely fully integrated. Some resource zones are entirely isolated from surrounding zones, but many zones are connected together. These connections allow transfers of water between zones through large pipes. The volume of water transferred is often significant. In 2004-05, the total volume of transfers between resource zones was 800 Ml/d, or about 5% of total water supply. Usually these transfers can operate only in one direction, from a zone with a surplus of water to one with less. These transfers may be of either treated or untreated water. Many resource zones receive water from beyond the zone, either through transfers from one zone’s supply network to another, or because some of the zone’s sources of water are outside the zone itself. For example, much of Birmingham’s water comes from reservoirs in Wales: the Elan aqueduct is 118 km long. The Ely Ouse – Essex transfer scheme moves water over 140 km from Norfolk to Essex through a system of rivers, channels and tunnels. The biggest tunnel is 2.4 m in diameter and 20 km long. This paper concentrates on the potential for developing additional transfers of water between different zones or from sources of water beyond the zone. It does not evaluate the costs and benefits of full integration of the water supply network to make a grid like the national electricity grid. This would require extensive redesign of the entire system of water supply, and no commentator has suggested that this is necessary. In any case, the first stage in the development of such a grid would be to improve the transfers between adjacent zones, especially where one of the zones suffers from a shortage of water. Environment Agency - Do we need large-scale water transfers for south east England? - 3 - Figure 1 Water company water resources zones Environment Agency - Do we need large-scale water transfers for south east England? - 4 - 3. New large-scale water transfers from other parts of England and Wales This idea has attracted significant attention in the press and from the public. There have been several previous studies into large-scale water transfers to meet water demand in south east England. Information published recently has drawn exclusively on these previous studies, and there have been no new assessments of the costs and environmental impact of developing these transfers. 3.1 Water Resources Board 1973 The Water Resources Board (WRB) had a duty to advise on the development of water resources in England and Wales. In 1973, it forecast that by 2006 the total demand for public water supply in England and Wales would be between 26,000 and 28,000 Ml/d. Based on this forecast, the WRB produced a water resources plan that included, in order of development (figure 2): • New reservoirs at Brenig (Wales), Kielder (Northumbria) and Carsington (Derbyshire) between 1976 and 1978. • Enlarging Craig Goch reservoir, in the Elan Valley by 1980. • Transfers from the Severn near Tewkesbury to the Thames near Abingdon, in 1984.