Forthbank Wind Energy Development - Partnerships for Renewables

Forthbank Wind Energy Development
13.3.72 A vertical section of Forthbank No.1 Mine shows the rockhead is detailed to be 19.2m bgl, with
the Mosie Seam at 22.85m bgl, the Lower Five Foot at 32m bgl and the Alloa Splint at 41.14m
bgl.
13.3.73 Extensive mine workings are noted to the north of the Turbine 1 location and off-site to the
east. From this plan, the workings appear to be in the Alloa Splint Coal and consist of room
and pillar mining.
Hydrogeology
Groundwater Bodies
13.3.74 A search of the SEPA RBMP GIS Database was undertaken to provide information on the
groundwater body in the region of the site. The database indicates that the site is underlain by
the Alloa bedrock and localised sand and gravel aquifers groundwater body. The quality of the
groundwater body has been classified by SEPA as ‘poor’ with a high degree of confidence and
the quantity of the groundwater has been classified as ‘good’ with a high degree of confidence
in 2008. Pressure types which exist on the groundwater body are noted as mining and
quarrying of coal, which is classified as a diffuse pollution source.
13.3.75 A search of the SEPA RBMP GIS database show that, like much of Scotland, the site is within
a Drinking Water Protection Area. The site is not within a Nitrate Vulnerable Zone.
Hydrogeological Classification
13.3.76 According to the Hydrogeological Map of Scotland, the site is underlain by an aquifer of limited
potential and without significant groundwater, referring to the superficial deposits. This is
expected to be underlain by the Lower Coal Measures, which is expected to be a highly
productive (but not extensive) aquifer. This aquifer is classified by SEPA as IFH, a highly
productive aquifer with intergranular flow.
Groundwater Vulnerability
13.3.77 The BGS groundwater vulnerability map of Scotland indicates that the site is underlain by
strata which is moderately permeable, i.e. fractured or potentially fractured rocks that do not
have a high primary permeability. The aquifers at the site vary in classification from
Vulnerability Class 1 (Only vulnerable to conservative pollutants in the long-term when
continuously and widely discarded and leached) to Vulnerability Class 3 (Aquifers are classed
as being vulnerable to some pollutants) in SEPA vulnerability classification scheme.
Site Investigation Data
13.3.78 From the intrusive investigations carried out, it was noted that Carse Clay had horizons of sand
which are likely to have high permeabilities. Plastic silt (i.e. low permeability silt) was noted to
be present at some locations.
November 2010 Chapter 13 Page 18
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