The impact of urban groundwater upon surface water - eTheses ...

STUDY SETTING
Man-made excavations and mining activities are common in the region, with numerous shafts
sunk into the South Staffordshire Coal Field and quarrying of sand and gravel deposits. Made
ground deposits are extensive, particularly in the Tame Valley, where large amounts of
material have been deposited on otherwise marshy ground. The deposits comprise mine spoil,
sand and gravel mixtures, often with substantial quantities of ash, slag and rubble.
3.4.3 Structure
The Coal Measures underlie the west of the region and to the east are unconformably overlain
by the Triassic sandstone that makes up the central area. The sandstones dip gently to the east
at less than five degrees. Within the unit subdivisions, the Wildmoor Formation lies
conformably on the Kidderminster Formation, with an unconformable contact with the
overlying Bromsgrove unit which, in turn, has a gradational contact with the overlying Mercia
Mudstone. The Birmingham Fault is a major structural lineament which juxtaposes the
sandstones of the central area against the Mercia Mudstones to the east. The Birmingham
Fault is a northeast-southwest trending normal fault with a downthrow of between 50 m and
200 m on the eastern side which has resulted in the erosion of the original overlying Mercia
Mudstone .
3.5 Regional Hydrogeology
The primary water-bearing unit is the Triassic Sandstone of the Birmingham Aquifer which is
unconfined over an area of 106 km 2 (Thomas, 2001) in the central portion of the study area.
To the east, the Mercia Mudstones are considered impermeable and the Birmingham Aquifer
becomes confined beneath them. The northern boundary of the Birmingham Aquifer is
defined by an anticline and to the south by a series of faults. To the west the Carboniferous
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