DRAFT Sustainability Appraisal Report for the Emerging Local Plan ...

8.17 The levels of nitrates for the river sites sampled by the Environment Agency within
Runnymede are generally in the grade range of 4‐6 (43) (moderate – very high) and phosphates
are generally graded 4‐5 (44) (high – very high). Sources of nutrients in the Thames and Wey
catchment areas include effluent from sewage treatment works and agricultural pollution (45) .
8.18 Within the Thames Basin region, eight out of 46 groundwater bodies are at good status
overall; 20 water bodies have been classified at good chemical status, and 16 at good
quantitative status ( 46) . These results are not expected to change by 2015. The main reasons
for poor status of groundwater quality are high level of nitrates, sources of which include
agriculture, effluent from waste and contaminated land sites, and vehicle emissions across
the basin. The main reasons for poor quantitative status are very high abstraction levels –
mainly for drinking water – which exceed the rate at which aquifers recharge ( 47) .
Water Resources
8.19 Water in Runnymede is supplied by Affinity Water for domestic and commercial purposes.
8.20 In London and the South East, groundwater accounts for around 70% of the total water
supply. The Environment Agency has produced Groundwater Source Protection maps for
Surrey and Runnymede (See: Figure 10 – Source Protection Zones in Surrey and Figure 11 –
Source Protection Zone in Runnymede).
8.21 The Environment Agency has subdivided groundwater source catchments into four zones.
Two of these are determined by the travel time of potential pollutants, the third by the
source catchment area itself, and the fourth is a ‘Zone of Special Interest’. This fourth zone
highlights areas where known local conditions mean that potentially polluting activities could
impact on a groundwater source even though the area is outside the normal catchment of
that source.
8.22 Thames Region is one of the driest regions in the UK with average annual rainfall of 690mm
as compared to the annual average for England and Wales of 890mm ( 48) . High population
density and dry climate mean that the region is classified as water stressed, having less water
available per person than other regions in the country. Catchment Abstraction Management
Strategies prepared by the Environment Agency for the Thames Region show that there is no
water available in the majority of the catchments and some catchments are assessed as overabstracted.
Figure 10 – Source Protection Zones in Surrey
43 Ibid.
44 Environment Agency ‐ 2009 River Quality data.
45 Environment Agency (2009) River Basin Management Plan, Thames River Basin District.
46 Ibid.
47 Environment Agency (2009) River Basin Management Plan, Thames River Basin District.
Page | 112 Runnymede BC FINAL Sustainability Appraisal Report – Feb 2013