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

GROUNDWATER FLOW TO THE RIVER TAME
surface run-off to effect baseflow. Inspection of the data (Figure 5.6) indicates that rainfall of
2 mmd -1 occur over
32% of the year. If a two-day duration of overland flow is assumed (Section 4.9.1) then the
estimate of time under baseflow estimate of 68% may be an over-estimation. The Tame is
assumed to be under baseflow conditions for between 36% to 68% of the year during which
time the groundwater component of river flow is at its most significant.
Precipitation data 1999 – University of Birmingham Weather Station
Precipitation
(mm)
Precipitation >
than
Number of
days
% of year
Mean 3 > 0 mm 224 61
Median 0.4 > 1 mm 156 43
Maximum 61.5 > 2 mm 117 32
Minimum 0 > 5 mm 57 16
Total 1096.6
Table 5.4 Summary of precipitation data for 1999 from the University of Birmingham
Weather Station.
Integration of the filtered river flow data was used to derive a value of 2.85 x10 7 m 3 for the
years total baseflow discharge derived from unknown sources between Bescot and Water
Orton. If this value is assumed to represent groundwater discharge and the groundwater is
assumed to be in steady state then recharge may be approximated as 28% of the annual
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