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

GROUNDWATER FLOW MODELLING
Variations of 0.1 – 0.2 m in the river and regional boundary heads in the FAT3D model
simulate the frequent (days-weeks) temporal variability likely to occur which induce a less
than +/- 8 % variation in discharge to the river. High river stages were also imposed to
investigate the impact of a major flood event. An increase in stage of 1.5 m reduced
groundwater discharge by 65% but the river still received a net gain. This is assuming the
system reacts fast enough for steady-state conditions to occur. More detailed investigations of
groundwater/surface water interactions under transient river flood conditions are undertaken
in the next section.
6.10 Investigation of groundwater-surface water interactions during a flood
event.
6.10.1 Conceptual model
The heavily engineered nature of the Tame catchment leads to a rapid rise and fall in river
levels during precipitation events. River stage flood rises of 50 cm are common and stage
rises of several metres have been observed. Daily river stage fluctuations of