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

MONITORING NETWORKS AND METHODS
Local groundwater flows across the riverbed were estimated using the Darcy flow and radial
flow equations in combination with head and conductivity data from the riverbed and
riverbank piezometers. Measurements of the temperature gradient across the groundwater-
surface water interface were taken across and along the riverbed to give a qualitative
indication of groundwater discharge to the river. Vertical temperature profiles from multilevel
piezometers were used to calculate rates of groundwater flow.
Groundwater head and river stage data were collected during the project and used in
conjunction with archive data to model groundwater flow. This was undertaken on a large
scale based on groundwater flow across the river flood plain (1.8 km 2 ) and on a local scale
(centimetres – metres) based on flow to the river channel. Groundwater/surface water
interactions under transient (river flood) conditions were examined using continuous head
data collected on river stage and groundwater levels in the adjacent riverbank.
The riverbed piezometer profile 8 (Figure 4.2) was selected for detailed study of both flow
and groundwater quality. Piezometers were located on both banks, 5 riverbed piezometers
were installed across the channel of which 3 were multilevel installations. This profile was
sampled on 4 occasions during the study period and detailed modelling of groundwater
surface water interaction was carried out.
Field equipment specifically designed and built for the project included drivepoint mini
piezometers, seepage meters, a temperature probe, a peristaltic pump, a riverbed coring device
and pressure transducer and logging systems to fit inside the narrow diameter shallow
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