Water availability impacts upon developmental issues--in particular housing demand--that may well be highly regionalized depending upon local economic prosperity and national profile.

Issue: 1/04

Water conservation has been one of the major research drivers over the past 10-15 years. It has affected w.c. design, drainage system sizing and vent design due to lower entrained airflows. It has impacted upon appliance design, from the development of the pressure-assisted flush and subsequent improvements to gravity operation, so ably discussed in PME (Nov. 2003), to the design of appliances such as washing machines and dishwashers. Water conservation has been promoted as "the right thing to do."

Figure 1. Current indicative availability--summer surface water.
Figure 1 illustrates water availability across England and Wales, and highlights the water shortages endemic in the Southeast (SE).1 The recent proposals by the Office of the Deputy Prime Minister to create a major housing project east of London along the Thames Estuary brings the issue into focus, as this area lies within a water shortage area. The interaction between planning legislation and the availability of water was highlighted further in this case by the Housing, Planning, Local Government and the Regions Select Committee (similar to a Senate Committee), which expressed dismay "that the water companies were not involved in any of the discussions [concerning] new housing for the SE. Preparations for the "

Figure 2. A water economy landscape? Climate change will bring both drought and flooding situations.
Thus, water availability impacts on the planning and development process, despite such additional supply. proposals as the introduction of desalination plants in several water company areas. Climate change will also affect the balance. Figure 2 illustrates in a possibly extreme way the dilemma that climate change will generate--both famine and feast in terms of water availability. Droughts in the U.K. have led to the reservoir levels falling to their lowest for decades. (The ruins of the village of Mardale in Cumbria, flooded in 1936, have reappeared above the reservoir surface in Haweswater.) Thus, development will require water economy and an assessment of the availability of supply.

Figure 3. Water leakage as reported by the Office of Water Services, 1997-2003.The 2002/03 increase includes a total of 0.41 million gallons per day from two of the 26 companies, Thames and Anglian.
This brings into focus the final element in the equation--water leakage. The Office of Water Services (OFWAT) oversees the water supply industry in the U.K. and sets annual targets for water leakage reduction through renewal of infrastructure. The industry average stands at 20%, despite pressure from government since 1997 to reduce leakage. Figure 3 illustrates the progress achieved in recent years in reducing leakage and its deterioration in 2002/03. In particular, the leakage rates experienced within Thames Water, covering some eight million users in the greater London area, have become the cause of severe concern. In the London boroughs north of the river--Westminster, Camden and Islington--leakage rates are in the order of 60%, comparable to those in developing countries. The water company claims that the age of the infrastructure (some pipes are over 150 years old), as well as the corrosive nature of the ground and cyclic pressures generated by dry summers and wetter winters, contribute to the losses. Plans to replace up to 50 miles of mains per year have been quadrupled.

An additional problem is supply pipe ownership. The small diameter connection from the main across the homeowner's land is deemed the responsibility of the owner and not the water supplier. However, few owners feel the need to check and repair their supply pipes until a terminal leak develops.

While the Scottish water supply industry is separated from these actions by devolved legislation, the water leakage figures are equally concerning. More than a billion litres of drinking water are lost every day in Scotland through leaks, equivalent to 45% of supply. Scottish Water, in an echo of the Thames response, concluded that this was "a reflection on the poor state of Scotland's water mains."