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

STUDY SETTING
Tame were effluent to the underlying aquifer (Land, 1966, Jackson et al., 1983). At the
present time, however, the recovery in water levels implies that the Tame is now receiving
groundwater discharge over most of its length with, perhaps, the exception of localised areas
adjacent to abstractions.
The Birmingham Aquifer has supported substantial abstraction in the past for industrial
purposes and limited public supply, reaching a peak of 60 Mld -1 (Figure 3.8) during the
1950s. This produced drawdown in some areas of up to 30m below the original postulated
levels (Figure 3.9a and b). Industrial closures and changing practices has led to a decline in
abstraction to approximately 13 Mld -1 (Environment Agency, 1999) and a consequent rise in
the water table (Figure 3.9 c and d). An investigation was undertaken (Knipe et al., 1993) into
the engineering implications of the groundwater rise because of concern about foundation
stability, basement flooding and the mobilisation of contaminants from previously unsaturated
waste.
The limited data available from pumping tests indicate a range in transmissivities of between
150 – 300 m 2 d -1 for the Birmingham Aquifer (Knipe et al., 1993). Values of conductivity and
porosity assigned to the aquifer subdivisions by Lovelock (1977) are as follows:
Formation Khorizontal md -1 Kvertical md -1 Porosity
Kidderminster 3.5 2.7 0.29
Wildmoor 1 0.83 0.27
Bromsgrove 0.93 0.53 0.28
Table 3.2 Hydraulic properties of the subdivisions of the Birmingham Aquifer
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