Environmental Engineering Reference
In-Depth Information
2.2 UK Aquifers
The UK obtains around 30% of its public water supply from groundwater,
with most of this water abstracted from the principal highly productive
bedrock aquifers. Examples include the Chalk of Southern and Eastern
England and the Permo-Triassic sandstones in the Midlands. However, it is
not only the public supply aquifers that are important. Many tens of thou-
sands of private (drinking water and industrial) supplies abstract from sec-
ondary (or moderately productive) aquifers and groundwater plays a vital
role in maintaining the baseflow in rivers and supplying water to wetlands
and the ecosystems that are dependent on this water. Figure 1 shows the
distribution of highly and moderately productive aquifers across the UK.
Whilst these may be the most productive aquifers, groundwater in other
areas (poorly productive aquifers) may also be locally important for baseflow,
wetlands and private water supply.
Two of the biggest concerns related to shale gas extraction are ground-
water contamination and over-abstraction of water. As a new industry in the
UK, these issues must be taken very seriously. Fortunately, the UK, with
highly developed and mature groundwater legislation, management/
protection policies and supporting tools, is in a strong position. This is in
contrast to the United States where regulation at the start of their develop-
ment of shale gas was limited and where groundwater issues are now arising
(see later). The UK Government(s) and their environment agencies regulate
effectively all potentially polluting industries and, in this context, a nascent
shale gas industry will be subject to exactly the same environmental regu-
lation. However, as it is not yet clear how the industry will develop, it is still
uncertain what any specific challenges will be in the UK environmental
setting. We know from the past that poorly regulated and uncontrolled in-
dustrial activity can lead to long-term environmental problems and costly
remediation. Examples include the contaminated land associated with for-
mer gasworks, fuel stations, mining and waste disposal before effective
regulation was brought into force.
Ahead of any new activity that may be potentially polluting, there is a need
to fully consider the risks associated with it, both in terms of health and
safety to humans and to the environment. Jackson et al.
5
identify two areas
where research is needed ahead of any development of unconventional gas
extraction: baseline monitoring and characterisation of pathways and
mechanisms by which contaminants may potentially pollute surface/near
surface water resources. In the UK, the British Geological Survey (BGS) has
also recognised this as being important and is carrying out baseline moni-
toring in those areas that have been identified for shale gas exploration
6
and
separately is developing (jointly with the Environment Agency) a 3D-model of
the spatial relationship between potential shale gas source rocks and the
principal aquifers in England and Wales. This work uses the BGS 3D Geo-
logical Model of Great Britain
7
and the Aquifer Designation dataset.
8
The
full extent of each rock type (shale and aquifer) has been mapped and/or
