Xylem SonTek FlowTracker2, User Manual

Page: 75 / 308

SonTek – a Xylem brand
FlowTracker2 User’s Manual (January 2019)
74
the Japanese method is the duplicate measurements performed of each depth and point
velocity measurements at a station. The Japanese national standard guideline for
determining the measurement interval for depth and velocity are dependent on the
measurement section width and are supplied in
Table 5:1 .
Table 5-1 - Predetermination of Measuring Intervals
River Width, B (m)
Measuring Interval of
Depth, M (m)
Measuring Interval of
Velocity, N (m)
Less than 10m 10 – 15% of B N=M
10-20 1 2
20-40 2 4
40-60 3 6
60-80 4 8
80-100 5 10
100-150 6 12
150-200 10 20
200 over 15 30
The Japanese method has two separate equations for determining the total discharge
based on the measurement section width. The equation of the Japanese method for
measurement section greater than 10m is given in
Equation 5:3.
Equation 5:3 - Japanese Method > 10m
𝑄 = ∑ �� ( 𝑏
1
− 𝑏
0
) × 0.5 �
𝑑
1
+𝑑
1
′
2
+
𝑑
0
+𝑑
0
′
2
� + ( 𝑏
2
− 𝑏
1
) × 0.5 �
𝑑
2
+𝑑
2
′
2
+
𝑑
1
+𝑑
1
′
2
�� × �
𝑣
1
+𝑣
1
′
2
�� +
Edge
�� ( 𝑏
𝑛
− 𝑏
𝑛−1
) × 0.5 �
𝑑
𝑛
+𝑑
𝑛
′
2
+
𝑑
𝑛−1
+𝑑
𝑛−1
′
2
� + ( 𝑏
𝑛+1
− 𝑏
𝑛
) × 0.5 �
𝑑
𝑛+1
+𝑑
𝑛+1
′
2
+
𝑑
𝑛
+𝑑
𝑛
′
2
�� × �
𝑣
𝑛
+𝑣
𝑛
′
2
��
Open Water
The equation of the Japanese method for measurement section smaller than 10m is
given in
Equation 5:4.
Equation 5:4 - Japanese Method < 10m
𝑄 =
∑ �� (
𝑏
1
− 𝑏
0
) × 0.5
�
𝑑
1
+𝑑
1
′
2
+
𝑑
0
+𝑑
0
′
2
� + �
𝑏
2
−𝑏
1
2
� × 0.5 �
𝑑
2
+𝑑
2
′
2
+
𝑑
1
+𝑑
1
′
2
�� × �
𝑣
1
+𝑣
1
′
2
�� +
Edge
���
𝑏
2
−𝑏
1
2
� × 0.5 �
𝑑
2
+𝑑
2
′
2
+
𝑑
1
+𝑑
1
′
2
� + �
𝑏
3
−𝑏
2
2
� × 0.5 �
𝑑
3
+𝑑
3
′
2
+
𝑑
2
+𝑑
2
′
2
�� × �
𝑣
2
+𝑣
2
′
2
�� +
Open Water
���
𝑏
𝑛
−𝑏
𝑛−1
2
� × 0.5 �
𝑑
𝑛
+𝑑
𝑛
′
2
+
𝑑
𝑛−1
+𝑑
𝑛−1
′
2
� + �
𝑏
𝑛+1
−𝑏
𝑛
2
� × 0.5 �
𝑑
𝑛+1
+𝑑
𝑛+1
′
2
+
𝑑
𝑛
+𝑑
𝑛
′
2
�� × �
𝑣
𝑛
+𝑣
𝑛
′
2
��
Open Water