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ASSETSABOVE Bathroom manufacturers have been building efficiency into their product ranges

Holding back the flood.Housebuilders have to maketheir water management

systems efficient and sustainable.ROGER HUNT reports.

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Water is a finite resource so reducing its use isan important objective in sustainable housing. Ata recent event Yvonne Orgill, CEO of theBathroom Manufacturers Association, referred tothe “great strides” bathroom manufacturers havebeen making over recent years to buildefficiency into their product ranges. Indeed,around 1,500 products are now listed under theWater Efficient Product Labelling Scheme and,with new British and European efficiencystandards soon to be launched, Orgillunderstandably suggests “sustainable productswill be the default position”.So much for the bathroom. What about themanagement and recycling of water? Reducing floodrisk is a key concern so the Environment Agency hasproduced ‘Building a better environment – A guide fordevelopers’ which gives practical advice on addingvalue to sites and the environmental issues whichmay affect them.What is frequently forgotten is that much of this caninvolve fairly basic thinking. Robert Huxford, directorof the Urban Design Group, explains that it often hasto do with using the charm and the potential of thesite to its maximum advantage. “There’s plenty ofevidence that, if you create an attractive environment,it will increase the value of the properties. There’s atension between some of the types of sustainableurban drainage systems (SUDS) that have beenadvanced and a brutal, engineered appearance. Itdoesn’t have to be like that, a decent engineer shouldbe able to produce a drainage system that is eitherinvisible or is beautiful to behold.”Huxford emphasises that culverted systems tendto aggravate flooding. They reduce the storagecapacity for the water and can affect flow ratesgoing downstream, they also tend to get blocked

which is far less likely to happen where there areopen channels. Hard landscaping is another major cause offlooding. “What you really want is a big sponge thatsteadily drains off the water. This is where SUDScome in to create a pattern of drainage; a water cyclerather like what it would have been before anybuildings were created,” says Huxford.SUDS schemes must address three main aspectsof surface water management: water quantity,quality and amenity. They take a variety of formsand are increasingly used to mitigate excessiveflows from stormwater and reduce the potential for

pollution from run-offs in urban areas. Manufactures are embracing the market for these‘soft’ solutions. Wienerberger has recently introducedthe Aquata Multi Brindled, a traditionally-styled claypaver. The specially shaped block provides thewearing course over the permeable beddingaggregate of the SUDS, so surface-run off can draininto the natural rainwater systems. “Almost three million properties are at risk offlooding from surface water, with up to five millionpeople potentially affected by all types of flooding inthe UK,” points out Mike Jepps, Wienerberger’spaver sales manager.

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“Almostthree millionpropertiesare at risk offlooding fromsurfacewater, withup to fivemillionpeoplepotentiallyaffected byall types offlooding inthe UK”

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Housebuilders have to take every site on its meritsand it is not always easy to balance financial returns,planning requirements and water management. NeillRobinson-Welsh, business manager for storm watercontrol at ACO, a company specialising in watermanagement, is a keen advocate of soft solutions butsays that the rules and regulations are not necessarilyhelpful to developers wishing to implement them.“Even though all the guidance is given for softsolutions, it actually bears little relation to reality. PPS3doesn’t help because when you have to put them intothe density that is required, there isn’t much spacebetween properties to incorporate the necessaryinfiltration techniques.” In larger developments with communal openspace it is much easier to incorporate softersolutions. Even then, the various regulations andauthorities can come into conflict.Robinson-Welsh cites one development where anengineer incorporated various soft solutions intohis design. For extreme events this had an outfallto a sewer but the water company refused toaccept this as the water was coming frominfiltration basins, saying that land drainage wasthe responsibility of highways.“This required a complete redesign of the wholedrainage scheme,” says Robinson-Welsh. “Itbecomes very difficult so, instead of these morenatural solutions, what tends to happen is thatengineers will do what is robust and what theyknow will be accepted. In many cases the softersolution would have been less expensive than theharder, engineered solution that designers end uphaving to go with.”One development where effective soft solutionshave been employed is Greenwatt Way, in Slough,Berkshire. The shared gardens and soft landscaping

areas provide permeable areas for infiltration. Inaddition, beneath the permeable paving for carparking, 50 cubed metres of geocellular infiltrationattenuation tanks collect excess surface water runoff.An impermeable swale system in the shared gardenprovides attenuation for a 100-year storm event tomitigate against flooding.The average consumption of potable water isaround 150 litres per person, per day but, as ChrisWilford, associate director at PRP architects,explains, it is much lower at Greenwatt Way. “We

achieved the target for Code for Sustainable HomesLevel 6 of 80 litres potable water per day, whilemaintaining acceptable flow rates on all taps, dueto rainwater harvesting.”The scheme has surface rainwater collection into acommunal underground storage tank in the sharedgarden. This water is then pumped back into thehouses to flush the WCs. In addition waterbutts on allhouses help collect rainwater from the roofs forirrigation and then any overflow from the butts alsoruns into the communal storage tank.

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OPPOSITE PAGE

TOP LEFT Wienerberger has recentlyintroduced the Multi Brindled Aquata, a

traditionally-styled clay paver TOPRIGHT Almost three million properties

are at risk of flooding from surface waterBOTTOM Both rainwater harvesting andgreywater recycling have been adoptedin all 101 affordable homes constructed

at Mariner’s Quay

THIS PAGE

TOP LEFT Ecoplay greywater systemTOP RIGHT Drainwave, an inline

flushing device launched in the UK byKonserve, deals with the problem of ‘dry

drains’ ABOVE An ACO storm tankbeing installed to provide stormwater

infiltration and attenuation RIGHTSwales store and convey surface water

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CONTACTSACO www.aco.co.uk

Bathroom Manufacturers Associationwww.bathroom-association.org

CME Sanitary Systems www.cmesansys.com

Drainwave www.drainwavesystem.co.uk

Environment Agency www.environment-agency.gov.uk

PRP Architects www.prparchitects.co.uk

SWIG www.sustainablewater.org.uk

UK Rainwater Harvesting Associationwww.ukrha.org

Urban Design Group www.udg.org.uk

Water Efficient Product Labelling Schemewww.water-efficiencylabel.org.uk

Wienerberger www.wienerberger.co.uk

Read Roger Hunt’s blog: www.huntwriter.com or follow him: www.twitter.com/huntwriter

Leadbitter Group to meet the requirements of theCode for Sustainable Homes Level 5, concerningwater consumption and conservation.As a high density development, many of theservices at Mariner’s Quay are community-based. Itwas decided to extend this approach to therainwater harvesting and greywater recyclingsystems to facilitate maintenance and to savespace. The Leadbitter Group installed foursystems, one for each of the apartment blocks,offering combined rainwater harvesting andgreywater recycling capabilities and a centralrainwater harvesting system to serve the houses inthe mews area.Water savings do not necessarily come without adownside. Wastewater flow rates, reduced due towater efficient appliances and fittings, may not besufficient to transport solids and clean the pipes,resulting in blocked or ‘dry drains’.This issue is addressed by Drainwave an inlineflushing device launched in the UK by Konserve.Located underground outside the building, it collectswaste water from basins, washing machines andshowers and, once it has reached a predeterminedcapacity, automatically tips, sending the watersurging through the pipes to increase the flushvolume down the drain. The problem of dry drains is a good example of theneed for a holistic approach to water saving andmanagement. In all cases the true carbon footprint ofthe various measures and devices needs to becarefully assessed on a site-by-site basis to ensuretrue environmental gains are being made.

At the UK Rainwater Harvesting Association,executive director David Byers believes that manyhousebuilders are not taking into account the benefitsof rainwater harvesting when it comes to waterattenuation. “Using it would help offset their othercosts for managing water on site while giving thehomeowner the benefit of reduced water bills.” Neal Landsberg, chairman of the Sustainable WaterIndustry Group (SWIG), says that, although much ofthe cost of installing rainwater harvesting systems isassociated with installing underground storage tanks,it need not be prohibitive. “If done during early sitework, this can be a small or marginal cost and theperfect opportunity to create a degree of water supplyindependence. This is a conceptual shift from simplydigging a ‘soakaway’.”In four houses at Greenwatt Way, greywaterrecycling has been installed so water discharged frombaths, showers and sinks is collected, filtered andused for WC flushing.An unsurprising proponent of greywater systems isManjit Lall, marketing manager for CME SanitarySystems which supplies the Ecoplay greywatersystem. He asserts that rainwater systems are greatas long as you keep getting rain. “With greywateryou are guaranteed the system is going to fill up andyou are tackling one of the major areas of water usewhich is toilet flushing.”Both rainwater harvesting and greywater recyclinghave been employed at the Seren Group’s Mariner’sQuay development, within the regenerated waterfrontarea of Newport, Wales. The systems were adoptedfor all 101 affordable homes constructed by the

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FURTHER INFORMATIONThe NHBC Foundation has published threereports, written by BRE staff: Water consumptionin sustainable new homes (NF29), A simpleguide to sustainable drainage systems forhousing (NF22) and Water efficiency in newhomes – an introductory guide forhousebuilders (NF20). They are available as freedownloads from www.nhbcfoundation.org

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THIS IMAGE An impermeable swale system in the shared garden atGreenwatt Way provides attenuation for a 100-year storm event tomitigate against flooding