Are more reservoirs needed if we are to head off future water shortages? Or is better management of existing water resources sufficient to meet future demand?
This week we ask:
Should water shortages in the South East be tackled by building more lowland reservoirs?
Rod Bridle, independent water consultant
Water resources are plentiful in the UK, but seasonal fluctuations make it necessary to provide storage to maintain supplies through dry seasons and dry years. Reservoirs present a more effective form of storage than groundwater recharge, icebergs and desalination.
Demand management advocates should remember that plentiful and wholesome water supplies were advocated by Chadwick as much for 'waterborne' sewage disposal as for wholesome water. The two functions were jointly responsible for the great improvements in public health achieved from the 1870s.
High standards have continued to the present, but plentiful amounts of water are not just a luxury, they play an essential role in maintaining hygiene. Reducing demand excessively may result in outbreaks of disease.
Reservoir projects take up land, often displace people and make dramatic changes to the environment. The anticipated downsides of lowland reservoirs are rapidly forgotten once the construction phase is over. Airports and motorways cause noise and pollution throughout their lives, but a modern reservoir would be a source of future pleasure to almost everyone.
The fundamental benefits of reliable water supplies would be enhanced by environmental and recreational benefits. Rutland Water is 'one of the finest examples of creative conservation in Great Britain'. Abberton is'outstandingly important' as a wintering locality for wildfowl. Not to mention access to fishing, boating and other open air pursuits that would, except through reservoirs, be largely denied to the large numbers who enjoy them.
UK legislation and practice is enlightened. It limits damage to the environment and looks after the minority who must move or otherwise suffer for the benefit of the majority.
Reservoirs most certainly should play a part in sustaining future water supplies. Would that we had built a Millennium Reservoir. It would have brought far more solid and lasting joys than the Greenwich Dome.
Peter Herbertson, water resources engineer, Environment Agency.
We must first learn to manage water resources more sustainably. 'Predict and provide is dead,' says John Prescott, it is time to 'Plan, monitor and manage'.
In the long run, demand management is a better option for society than transferring the impacts of high consumption to a series of lowland reservoir sites. Peak demands caused by garden watering can be moderated by metering and tariffs. Demand from the 1.1M new homes recently proposed for the South East can be moderated by building water efficient homes with metered supplies. Friendly persuasion and price pressure can encourage all consumers to use less.
Leakage reduction is now freeing up more resources. Leakage for 1998/99 in the South East was 1,066M litres/d for the three large water service companies and 327M litres/d for the seven water only companies. Reducing this by a third would yield enough water to meet the needs of over a million new homes in the South East. Such savings equate to the yield from several smaller reservoirs, or one very big reservoir in the South East.
Leakage is still a major resource. There remain major supply imbalances, not only between companies, but also within the larger companies. Greater connectivity between companies is essential if we are to make best use of precious water resources.
Lowland reservoir sites in Essex, Kent, Sussex and Oxfordshire are all likely to be strongly opposed by local residents and environmental activists. The 1979 application to build a reservoir at Broad Oak in Canterbury was refused on the grounds that the water authorities had not struck the right balance between their needs, and those of the local community and environment. Water companies have more to do to convince us that they have exhausted all the opportunities for managing demand before they increase supply.