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Code for sustainable homes. Water efficiency and surface water runoff Jonathan Reed Atkins Water & Environment. Introduction. Atkins Water – why important? The Code objectives Water efficiency Surface water runoff Conclusions. Atkins at a glance. With a turnover of c.£1.2bn, Atkins is:
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Code for sustainable homes Water efficiency and surface water runoff Jonathan Reed Atkins Water & Environment
Introduction • Atkins • Water – why important? • The Code objectives • Water efficiency • Surface water runoff • Conclusions
Atkins at a glance With a turnover of c.£1.2bn, Atkins is: • One of the top 10 Best Big Companies to work for • The largest engineering consultancy in the UK • The largest multi-discipline consultancy in Europe • The 4th largest design firm in the world • Voted no.1 with ‘Best Reputation’ in Environment
Water “[water efficiency has] minimum standards that must be achieved at every level of the code, recognising [it’s] importance to the sustainability of any home.” Why? • Water efficiency can be implemented now; • Range of sustainability benefits – energy, environmental impacts, etc. • Improved adaptation to climate change. Two areas covered by Code: • Water efficiency • Surface water run-off
Water Efficiency • Weir Wood Reservoir in August 2005 • Lowest recorded levels • Increase in demand for water should be minimised • Demand for water measured as a ‘Per Capita Consumption’, i.e. litres per head per day
Surface water run-off and flooding • Impact of hard surfacing on run-off, infiltration and drainage
Water Efficiency • Code Objectives
How water is used • Components of demand • 2/3 of total consumption through: • Toilets • Taps • Showers Components of household water use for average days (WRc 2005)
Step 1 – minimise water use • Toilets • Dual flush 6/4 litre • Can be reduced further • Showers • Flow rates of 6-9 l/min • Aerating shower heads • Flow restrictors • Baths • Shaped baths
Step 1 – minimise water use • Taps • Aerated taps (downstairs sinks) • Flow restrictors • Appliances • Dishwashers • Washing machines • External • Fit a water butt
Water Efficiency • Code Objectives
Step 2 – use of non potable water • Rainwater and greywater • Risk assessment • Secondary pipework system
Surface water runoff New development has two main impacts: • Increases runoff rates – making flooding worse elsewhere • Reduces volume available for floodwater in the floodplain
Surface water run-off • Code objectives
PPS25 – Development and flood risk • Environment Agency are statutory consultees • Aims to minimise the risks of development in flood risk areas • Areas designated by the risk of flooding
Run-off vs Time for storm event Hard surfacing Natural runoff rate Run-off Time Benefit of SUDS • Manages water at source and reduces peak flows • Improves water quality • Improves both visual and natural habitats
SUDS techniques • Permeable paving • Allows water infiltration • Swales • Flow attenuation and conveyance • Green roofs • Reduce run-off volume and rate • Underground storage • High density development
Long term maintenance of SUDS • Maintenance • Long term maintenance of SUDS needed • Who by? • Sewerage undertaker • Local Authority • Highways Authority • How? • Early consultation needed • Sewers for Adoption • Model agreements for SUDS
Conclusions • Water efficiency • Water efficient appliances • Toilets and showers • Non potable use of water • Rainwater or greywater for toilet flushing • Water butts • Surface water runoff • SUDS to reduce and improve surface water runoff • Flood risk controlled through links with PPS25