East Cambridgeshire District Council Water Cycle Study Detailed ...

Stage 2 Water Cycle Study: Final Report
Sept 2011
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Cambridgeshire Horizons
East Cambridgeshire – Detailed WCS
• in the UK, there has been relatively little research on toxins in streams, lakes and sediments,
as the problems are thought to be limited. However, climate change may alter this perception.
Climate change studies, especially in relation to water quality and ecology, are at fairly early
stages and the outcomes are subject to considerable uncertainty. However, understanding the
processes and mechanisms controlling water quality and ecology, and how these combine and
interact, is essential for sustaining potable water supplies and conserving river systems. 30 As
such, the findings of this study and planned adaptation and mitigation options should be
updated when further research and guidance becomes available.
One of the key climate change adaptation challenges will be managing increased wastewater
flows (from new developments) while protecting the water environment in the area, particularly
where the impacts of climate change on the water environment are still uncertain. The Detailed
WCS has undertaken a sensitivity analysis on the vulnerability of water quality to climate
change impacts through assessing the impact of reduced summer flows on dilution of
wastewater discharges. A broad brush sensitivity was undertaken using RQP whereby the
Q95 of the receiving watercourse has been reduced by 20% to model a reduction in summer
flows. The consent requirements for the WwTW were then determined assuming the WFD
objective of ‘no deterioration’ under these conditions compared to those under the existing
climate. These results are summarised in Table 3-7. It should be noted that only WwTW that
have data for river flows in the receiving watercourses have been assessed as the RQP
analysis cannot be undertaken without estimates of river flow statistics.
The assessment shows that under potential future climates, WwTW consents are likely to need
to be tighter than existing consents, but in the majority of cases these are small changes and
discharge consents are still within the LCT.
Climate change, water quality and adaptation
Table 3-8 provides a summary of the potential climate change adaptation and mitigation
measures that could be considered in the East Cambridgeshire District with regards to water
quality and wastewater services infrastructure. The organisations likely to be responsible for
leading these measures have been identified alongside the suggested timescale for these
actions to start being taken forward (Immediate, Medium (1 - 10 years) and Long (10+ years)).
30 Potential Impacts of Climate Change on River Water Quality. Science Report SC070043/SR1, Environment Agency 2008