Xylem SonTek FlowTracker2, User Manual

Page: 82 / 308

SonTek – a Xylem brand
FlowTracker2 User’s Manual (January 2019)
81
b) Calculating of effective depth. The effective
depth is defined by the distance between the
streambed and the bottom of the ice or slush
in the case slush is present,
i). 0.2 depth setting = a + 0.2C
ii). 0.8 depth setting = b – 0.2C
iii). 0.6 depth setting = b – 0.4C
c) Station area is calculated by multiplying the effective depth and station width.
Weighted Gauge Height 5.1.6
The Weighted Gauge Height during a discharge measurement is the mean water level
calculated at the monitoring site during the measurement time. It is important that an
accurate mean gauge height is determined as this is used with the discharge measured
to develop stage-discharge relationship for the monitoring site. The methods
implemented in FlowTracker2 for determining the weighted gauge height during a
discharge measurement is the
average of both the Discharge Weighted and Time
Weighted gauge height.
a) The discharge weighted process is based on the discharge calculated within the
time interval associated with each set of gauge height readings. The equation of
the discharge weighted method is given in
Equation 5:5.
Equation 5:5 - Discharge Weighted
𝐻 =
𝑞
1
ℎ
1
+ 𝑞
2
ℎ
2
+ 𝑞
3
ℎ
3
+ 𝑞
𝑛
ℎ
𝑛
𝑄
where,
𝐻
is the mean gauge height,
Q is the total discharge,
q is the discharge measured between time interval of gauge height readings,
h is the average gauge height readings taken between time interval.
b) The time weighted process is based on the arithmetic mean of the gauge height
calculated within the time interval associated with each set of gauge height
readings.
Equation 5:6 - Time Weighted
𝐻 =
𝑑
1
ℎ
1
+ 𝑑
2
ℎ
2
+ 𝑑
3
ℎ
3
+ 𝑑
𝑛
ℎ
𝑛
𝑇
where,
𝐻
is the mean gauge height,
Figure 5:6 - Effective Depth