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

MONITORING NETWORKS AND METHODS
There was a significant problem in determining the inputs from tributaries and industrial
discharges between the measurement points, and the diurnal variation in discharge from
sewage treatment works upstream. This added additional uncertainty in the calculation of the
actual accretion related to baseflow input over the study reach.
4.3.2 River cross sectional discharge calculation
Stream discharge measurements were carried out as detailed in Section 4.2.1. Values of flow
velocity were obtained at 0.5m intervals across the river at a level of 0.6 m of the total river
depth at each measurement location. The velocity at 0.6m of the total depth is generally
representative of the average velocity occurring over the entire depth interval. The total river
discharge may be calculated using the mid-section method (Cey et al.,1998):
Q
=
n
∑
i = 1
( X
Q= total discharge
i + 1 − X i)(
U iY
i + U i + 1Y
i + 1)
/ 2
XI = distances to successive velocity measurements from the river bank
Ui= velocity measurement at each interval
Yi= depths at each interval
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