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

6.9.3 Results and discussion
GROUNDWATER FLOW MODELLING
The MODFLOW (Table 6.6) and the FAT3D (Table 6.7) models indicate increases of 20-
38% in groundwater discharge to the river for a regional water level rise of 0.5 m. If
contaminant concentrations in the groundwater remain the same, i.e. are not diluted, then the
river is likely to receive a greater total contaminant mass loading derived from groundwater if
increased recharge due to climate change occurs. The recovery of groundwater levels in
Birmingham (Section 5.2) by several metres since the 1950s has undoubtedly led to a
significant increase in groundwater discharge to the river. However, water table rebound in
the Tame Valley appears to have stabilised and further increases in groundwater discharge are
unlikely to result from this if current rates of abstraction are maintained.
River gain
(m 3 d -1 )
Variation in
river gain
(%)
River loss
(m 3 d -1 )
Variation in
boundary
heads (m)
Variation in
river level
9683 0 34 - -
13364 +38 0 +0.5 -
6774 -30 798 -0.5 -
(m)
6837 -29 805 - +0.5
13235 +37 0 - -0.5
Table 6.6 The impact of MODFLOW boundary head variations on discharge to the river
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