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

GROUNDWATER FLUX
Based upon the limited data set it would seem that the groundwater discharge from the
Birmingham Aquifer does not significantly reduce the current surface water quality. In some
cases the groundwater may improve surface water quality by diluting sewage effluent
discharges and upstream sources of Cu, Zn, Ni. The Tame is at present categorised within the
worst classes E/F (poor/bad) under the General Quality Assessment (Environment Agency,
1999), primarily due to excessive levels of biological oxygen demand (B.O.D) and
ammonium from pipe end discharges. Should these pipe end discharges be halted the river
quality is likely to improve although the minimum baseflow (180 Mld -1 , Section 6.3.2) at the
downstream end of the study reach may be reduced by 50%. Groundwater discharge from the
aquifer will supply a contaminant loading to the river from urban sources but not at levels
sufficient to break the EQS limits, except in localised areas of the riverbed where high
concentration contaminant plumes are discharging.
346