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

WATER QUALITY INTERACTIONS
these factors need to be considered when comparing surface water results, even over
relatively short distances.
For reasons of time and money, the data set used in this study has not been exhaustive, and
the toxicity standards that have been applied have had their limitations. Nevertheless, a
number of broad conclusions can be drawn, not least, that the quality of groundwater
discharging into the Tame is better than might have been expected, despite Birmingham’s
long industrial history and the intensive urbanisation that has taken place. Sampling has
shown that in many places in the study area, the quality of the groundwater is better than the
quality of the surface water, and that in these areas the groundwater may be contributing to
improved river quality and helping to sustain the riverbed ecology.
In other areas, it is clear that contaminant plumes discharging through the riverbed are having
a detrimental effect on life within the riverbed although this is generally mitigated by dilution
of the plume within the main surface water column.
It has been established that the levels of all the determinants used to gauge groundwater
quality are above natural background levels. Although these elevated levels in the
groundwater are having only a very limited impact on the existing quality of surface water,
they could impede future efforts to improve surface water quality (e.g. if all pipe discharges
into the river were to cease).
The most important determinants for surface water quality (EQS), particularly in the
hyporheic zone, appear to be SO4, Cu, Ni, TCE and VC because of their widespread
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