Article from Water and Environment Manager – 20 April
2003
www.ciwem.com
Water companies have had a statutory duty to promote the efficient use of water since February 1996. Rob Lawson of Entec reports on a new tool for the development of domestic water efficiency.
Nearly 7.5 million cistern devices and over 10 million self audit packs have been issued to domestic households in the last 6 ½ years. It is clear from these statistics that this statutory duty has resulted in water efficiency activity. But how effective has this activity been in reducing domestic consumption.
The answer remains unclear for a number of reasons. Water efficiency savings are relatively small on a flush-by-flush, house-by-house or day-by-day level. In fact they are small enough to be lost in the ‘noise’ of a typical district meter.
A number of studies have tried unsuccessfully to monitor the effectiveness of water efficiency activity at district meters. But the savings are there if you look in the right place (this often means monitoring at household or appliance level). A study by Southern Water into the water efficiency of retrofit dual flush toilets found that on average the devices reduced total domestic consumption by 8%. At a national level this is equivalent to 1015 Ml/d.
Can water resource planners be confident about these savings? Uncertainty seems to have been a major stumbling block in preventing mainstream acceptance of this part of the ‘twin-track’ approach. The yield, cost, risk and uncertainty of traditional resource options is relatively straightforward to determine, but such certainty in the effectiveness of water efficiency has been sorely lacking to date.
It is not surprising therefore, that Ofwat is keen to see the results of a recently-completed UKWIR, has developed a process that will enable companies to come up with robust, reliable and defendable estimates of water efficiency savings. The ultimate aim is that credible demand-side solutions will stack up against supply-side options in future water resource planning reviews.
The project, which has been running for the past three years, has generated considerable interest in the industry, with 11 water companies, the Environment Agency and Water Service (Northern Ireland) volunteering to take part in 14 demonstration projects that tested the original draft methodology. The experiences gained from these demonstration projects resulted in a refined Framework Process based on sound principles of
Development of a well-formed research objective is a fundamental requirement of any study and will drive all aspects of study design and analysis. The implications of the objective need to be considered carefully, by conceptualising the issues that will need to be addressed. A key consideration is how to capture or account for the huge variety of human behaviour that can disrupt or overtake even the most carefully planned project. The risk assessment and determination of costs will help to inform researchers if project objectives can be met within budget and without undue risk to project success.
The report includes tools for defining appropriate sample sizes, monitoring periods and monitoring locations developed using a combination of statistical theory and first had experience of the niceties of water efficiency research.
Entec will be one of the first companies to test truly the
final Framework Process by managing a jointly-funded research project for
the Environment
Agency/Dee Valley Water into the disaggregated savings due to metering.
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