Reservoir renaissance

April 1, 2006
Reservoirs have a long history but are out of favor. However, with pressure on water resources and the prediction of more droughts, CIWEM Executive Director, Nick Reeves, suggests that it’s time to re-think reservoirs.
Click here to enlarge image

Reservoirs have a long history but are out of favor. However, with pressure on water resources and the prediction of more droughts, CIWEM Executive Director, Nick Reeves, suggests that it’s time to re-think reservoirs.

Grinning weather forecasters happily tell us that “there is only a small chance of rain,” despite knowing that the possibility of no rain is much greater. What are they playing at? In these days of global warming, anyone with half a brain should be praying for the stuff.

Despite a cold grey winter, some of our reservoirs are running low on water and - as I write - the UK utilities company, Southern Water, is seeking a license to divert it from the Medway to Bewl Water Reservoir. Nearly four million people have been living with a hosepipe ban since last summer and residents in Folkestone and Dover will be forced to have water meters. A combination of climate change, drought and ever increasing demand is creating an alarming situation across southern England.

The public have only just gotten used to the idea of a looming energy crisis and an affordable housing problem. Now, to add to the misery, there are dire warnings on water. And this is not just a local difficulty. In 2005, France received just half its average rainfall and the French government is predicting an equally dry 2006, resulting in crop failures and restrictions on domestic consumption. Meanwhile, desertification is gathering pace as parched Portugal and southern Spain lost millions of acres of woodland to forest fires. Across Europe many farmers are moving from water-hungry crops to those that thrive in hotter and drier conditions. The specter of global warming is growing and there is little reason to believe that things won’t get worse. We are, after all, hard-wired to profligate consumption and water waste.

As we build more houses, drain more wetlands, lay more concrete….we use more water. It’s a discredited formula for living that does us no credit at all. The United Nations reminds us that every time we in the developed world flush a lavatory, we pump away enough water to supply the daily needs of someone in the developing world for drinking, cooking and basic health needs. Globally, £50 billion (t73 billion) a year is spent on new water resources. Those in the know say it’s not enough and that it should be doubled. There is a crisis and it’s global and local.

The UK government decision to allow the Folkestone and Dover water company to force water meters on its customers has intensified the debate on water efficiency, suggesting that there could be a “reservoir renaissance.” As part of a multi-faceted strategy to conserve water, reservoirs might just make sense. Reservoirs can be good for water conservation and for the environment provided they are carefully planned as part of a package of water demand management measures. Reservoirs ensure that water is available during long dry periods and they help to minimize abstraction from our rivers. Other benefits include floodwater control, renewable power generation and irrigation. There are also other important social benefits, such as recreation and conservation, and the contribution they can make to enhance local environments and the landscape. For more than 5,000 years reservoirs have provided water and power… they can’t be as bad as some would have us believe.

CIWEM Executive Director, Nick Reeves
Click here to enlarge image

But reservoirs do come at a cost - and I’m not just talking vast sums of money. In an urban-fixated country like the UK, location is everything and to put reservoirs where they are needed most could involve the displacement of many people and communities, and the destruction of important landscapes. The construction process can harm the environment too, causing problems to downstream flow patterns with impacts on fish migration, biodiversity and microclimates. And convincing the planners is always going to be a problem. Given the seriousness of finding and storing enough water for all, it is surely time to talk.

In the meantime, the UK government has announced that all new homes must have water saving devices that will reduce consumption by 20%, but it’s not enough. Voluntary building codes on water efficiency must become mandatory and all existing properties must be water efficient too. Unless we can reduce consumption by nearer 40%, we will be in serious trouble. So we must ask: just how sustainable is the Sustainable Communities Plan when development in southern England has already breached environmental limits?

Over time we have come to find more ways of using water. Agriculture is a huge consumer. Around 10,000 gallons is needed to produce the grazing required for a pound of beef, which is a fact that will shock the most ardent of meat-eaters. On a domestic level, it is estimated that we are using one gallon a day more per person than we did ten years ago, and that we use twice as much as we need to maintain a healthy lifestyle.

What to do then? Well, metering - with safeguards for the least well off - can make a difference, making us think more about turning on the tap. When residents on the Isle of Wight were metered, consumption fell by around ten percent and yet only around one in four of us have them.

Argument for a National Grid for water is a sign of the increasingly desperate position we face. Water is heavy stuff and the cost of pumping it around the UK, up hill and down dale, would be astronomical and consume a lot of energy. The vital measures we need are to increase investment, cut waste, reduce leakage and reconsider reservoirs. The £3 billion (E4.38 billion) spent by water companies on improving delivery is simply not enough.

A quarter of all water supplies is lost through leakage and, although the water companies are doing all they can, conflicting pressures from regulators and from shareholders means that they are not yet investing enough. For now, water supply problems in Britain only mean parched gardens and dirtier cars. Elsewhere in the world, millions die for the want of clean accessible water and tensions about supply and ownership are vastly more serious. They are matters of life and death.

At last we have come to understand that oil and gas are scarce and finite resources. We must hope that very soon we also learn that water is also a precious commodity. In the UK, if we truly value our environment and the rivers and waterways that nurture it, we can no longer plunder them at will. It behooves us all to think more strategically about water supply and storage. Most of us will surely have to pay more for water and use less of it. We will need to capture and store more, even in our own gardens and in our public parks. But we may need reservoirs too.

Unless we want to see rivers like the Kennet vanish from the landscape - as some have vanished already - we must forget reckless abstraction that is tolerated now. It’s time for a “blue revolution” in water use and storage.

The need for water for living, growing food and for renewable, non-polluting power is paramount to society. Storing wet season run-off is a long-term sustainable method of providing this; however, reservoirs need careful planning with environmental and social impact studies in order to test their viability. Needless to say measures should be taken to minimize any negative impacts, and we must see that reservoirs are just part of the answer for sustainable water supplies.

Author’s Note

Nick Reeves is the executive director of the Chartered Institution of Water and Environmental Management (CIWEM). For more information about CIWEM activities and resources, visit the website:

Rainwater harvesting market triples in UK

The use of rainwater harvesting systems is a proven, cost-effective way to address water shortages, according to the UK Rainwater Harvesting Association. Once widespread throughout the UK, such systems fell out of fashion with the introduction of mains water supplies, but they are now experiencing a renaissance in this country, which has seen a tripling of the market in the last two years.

A rainwater harvesting system collects water that falls onto the roof of a property for subsequent use in non-potable applications, such as toilet flushing, clothes washing machines, car washing, and garden watering. Typically, independent trials have shown that a domestic rainwater harvesting system reduces mains-water consumption by approximately 50%.

The systems are also extremely cost-effective when used on commercial and public buildings where there is a combination of large roof area and a high consumption of non-drinking water for toilet flushing or commercial processes.

When light rain falls, much of the water is re-absorbed into the atmosphere rather than finding its way into the water table or reservoir system. A rainwater harvesting system, however, intercepts this water conserving it for subsequent use. Conversely, during heavy downpours, rainwater harvesting systems help to alleviate flood-risks by easing flows into the stormwater management grid, minimizing waste and disruption. Use of harvested rainwater for non-potable applications also saves the energy that would otherwise be wasted in bringing water un-necessarily up to mains, drinking water standard.

Upcoming CIWEM conferences

Integrated Urban Drainage
May 10th, 2006, SOAS, London

The key objectives of this conference are to emphasize the need for integrated urban drainage (IUD) for surface and foul waters, analyze the Defra IUD pilot scheme, review examples of good practice and discuss actions to overcome existing institutional barriers. These will be achieved by addressing the impact of the Water Framework Directive, examining the impact of climate change and by looking at the sustainability of different solutions, amongst others.

Water Framework Directive - Ecological Status, Monitoring and Reporting
June 8th, 2006, SOAS, London

Catchment Management
July 18th, 2006, SOAS, London

For more information on these CIWEM conferences, contact Bob Earll, CMS [email protected]

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