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

GROUNDWATER FLOW TO THE RIVER TAME
The analyses of the river flow data using the baseflow filter (Section 4.9.1) removed the effect
of runoff and wet weather conditions. The range in baseflow is estimated to be from 180 to
518 Mld -1 with a mean dry weather flow of 308 Mld -1 at Water Orton (Table 5.1). Estimates of
discharges from known sources (including tributaries) across the study reach are 52.6 Mld -1
(dry weather conditions) and 77.2 Mld -1 (mean conditions). The increase in baseflow across
the reach was obtained by subtracting the mean value of known discharges, plus the flows at
Bescot and Calthorpe, from the flow at Water Orton.
Analyses of all discharge data Baseflow filter applied
Gauging
Station Mean Median Max Min Mean Max Min
Mld -1 Mld -1 Mld -1 Mld -1 Mld -1 Mld -1 Mld -1 %
Bescot 213 148 4040 27 131 225 48 68
Calthorpe 81 40 5671 13 38 86 13 79
WaterOrton 506 338 9150 180 308 518 180 68
Table 5.1 Baseflow analyses of 1999 gauging station data
Time
under
baseflow
This produced a range for the increase in flow of between 41 and 130 Mld -1 for the minimum
and maximum periods of baseflow. This represents a direct inflow of between 1.7 to 5.5 m 3 d -1
per metre length of channel (total 23.8 km) and comprises 23% to 25% of the flow at Water
Orton. The inflow under mean baseflow conditions is 2.6 m 3 d -1 inflow per metre length of
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