Water Cycle Study - East Devon District Council

Exeter and East Devon Water Cycle Study
7.8.12 Current potable water demand in the WCS in 2006/07 was 39.96Ml/d. The business as usual case
(scenario 1) based upon constant existing PCC rates and varying new pcc rates shows that if no
demand management measures were implemented other than the increased meter penetration
proposed by SWW, an additional 6.62Ml/d of potable water will be required in the study area by
2026. This is approximately equivalent to almost two and a half Olympic size swimming pools on a
daily basis, or an increase in household demand of 16.6% between now and 2026. This is the
worst-case scenario and it should be highlighted that South West Water’s own proposals for
meter penetration are to meet 80% metering by 2014/2015 which is close to the Environment
Agency’s proposals on 95% meter penetration of the existing population by 2016.
7.8.13 The implementation of the various levels of the CSH has been tested alongside SWW’s proposals
on metering (scenarios 2, 3, and 4). By comparing the difference between scenario 1 and 2 it is
possible to see that the introduction of the CSH level 5 for new homes built from 2009 onwards
reduces the additional demand by an additional 2.9ML/d by 2026. With less stringent
implementation of the CSH as shown in Scenarios 3 and 4 but with the addition of sequentially
reduced PCC demand from existing metered properties, the total demand by 2025/2026 can be
reduced by a further 3.8 ML/d compared to that in scenario 2. This creates a water neutral
position to the end of the planning period.
7.8.14 The analysis also shows that the greatest reduction in water demand can be achieved by reducing
demand in the existing population. This is because the existing population account for a larger
proportion of the total population than the population from new development. Therefore though
measures such as CSH, targeted at new developments have a positive impact upon total demand
they should be used in conjunction with proposals for the existing population in order to achieve
maximum reductions in total demand. Comparing the scenarios it can be seen that the increase in
demand is not as steep over the planning period with the use of CSH measures and reduces
further with the reduction in PCC of existing population which can have a dramatic affect.
Scenario 4 details a reduction in PCC each year for existing metered houses of 1.5 l/h/d which
lowers the existing metered housing PCC to 114.74 by 2026, below that required by CSH level 3.
However it must be accepted that a reduction in 1.5 l/h/d per year cannot be sustained over the
long-term and will be constrained by technology at some point.
7.8.15 Water neutrality (scenario 4) can be achieved from 2009 to 2026 by implementing a variety of
measures. This includes SWW proposals for 80% penetration by 2014/2015, though aims should
be for the Environment Agency’s proposals on compulsory metering of 95% of existing properties
by 2016; the implementation of the CSH (as described above) and a reduction in the existing PCC
of the existing population. This would need to be achieved through the implementation of water
efficiency measures such as retrofitting, education and encouraging water efficient devices.
7.9 Future implementation of demand management measures
Metering
7.9.1 The measures included in the scenarios in the section above, in some cases, will not be practical to
implement. The implementation of Environment Agency metering of 95% of existing properties by
2016 is an ambitious target and requires around 6,000 properties a year to be connected to a
meter at a cost of up to £500 each. Currently 60% of customers in the South West Water area
are connected to a meter which is almost double the national average. Since October 2007, water
companies within seriously water stressed areas have been given extended powers to increase
83 Ref EWCS April 2010