Water management policy …Lets not take our eyes off the ball!
February 15th 2007 Looking out of the window at a wet and windy wintery scene, it is hard to remember the salad days of last summer and the almost daily clamour surrounding watershortages, the imposition of hosepipe bans, and drought orders in the offing. Water shortages; what water shortages?
At a recent CIRIA seminar, an Environment Agency
spokesman highlighted that the availability of water
ranges widely throughout the UK due to average local
rainfalls varying by a factor of up to 100%,and the waterretentive
characteristics of local geology.
In and around the London area the already delicate balance between demand for water and available water resources will become even more fragile with the announced intention to build up to 800,000 additional new homes in the region, along with the associated social infrastructure (transport, schools, leisure facilities, retail and employment etc), at an average rate of 28,900 houses per year.
Capacity studies predict that without new resources or water efficiency measures, over the next 20-years supplies will at best exactly align with demand across the region, with one-third of the region suffering a water-deficit of up to 15% - rising to more than 40% in the worst-hit areas. Only by assuming water efficiencies of more than 20% and the availability of some new resources can the current fragile balance be maintained. Current water-supply limitations are illustrated by the position in Kent where throughout the County’s rivers, level controlled areas and groundwater,over-abstraction and over-licensing are widespread; only in a few areas can new demands for water be met without this position deteriorating still further, whilst the intention remains to create 31,000 new homes and 28,000 new jobs in the Ashford Growth area alone.
It is against this backdrop that companies such as Freerain are experiencing 100% year-on-year growth; reading this statistic across the whole of the UK market is therefore encouraging at first glance, although this growth is from such a low base that its overall impact on a national scale will inevitably be limited.
For rainwater harvesting to have any real impact on national water-supply management,government needs to legislate to ensure that where appropriate new homes and commercial buildings be fitted with rainwater harvesting systems; a grants regime is also advocated to assist retro-fitting systems to existing properties, similar to schemes already in place for solarheating systems.
Set alongside other straightforward water economy measures (domestic consumption per capita in the south-east is double that on Humberside, for example), integrating rainwater harvesting into national water management policies would progressively have a substantial impact on the usage of mains water. Properly harvested rainwater – using modern hygienic customised systems – when used for domestic nonpotable applications such as toilet-flushing, clotheswashing machines and outside taps displaces around 200-litres of mains water per person per day. A very substantial year-by-year saving when scaled up across a realistic case-study. In the Ashford Growth Area example above, this would amount to a saving of around 2.3M cubic-metres of water per year in this one area alone. Water savings are even more spectacular on nondomestic properties which combine the attributes of large roof areas and a high demand for non-potable water, where the capital-cost pay-back period can be as little as two years. Office blocks, leisure stadia, schools and commercial premises all fall readily into this category.
Left to market forces, it seems unlikely that rainwater harvesting in this country will quickly achieve the scale of the industry in Germany which is three hundred times that of the UK. Current growth in the UK market is vigorous at more than 100% per annum, but from too low a base seriously to impact on the overall water supply situation. Given Government prompting – similar to the German experience for example – could rapidly change this equation thereby enabling the overall objectives of national water management policies to be met.
But let’s not wait until next summer’s drought before thinking of acting! More articles from Rainwater Harvesting Association: | 
