Xylem SonTek River Surveyor M9, Системное руководство

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SonTek, a Xylem brand
124 RiverSurveyor S5/M9 System Manual (February 2013)
profile for each station is computed from data from all valid cells above the riverbed. The width
of a single station is determined to be the sum of half the distance to the previous station and
half the distance to the following station. This method assumes that the velocity profile at each
station represents the mean velocity for the entire rectangular station area.
Figure 108. Basic River Discharge Measurement Method
Each station is measured for a significant time to remove any environmental and temporal varia-
tion in the water velocities. Typically within the USGS, the recommended duration of measure-
ment for a single station is 40 seconds. However, in particularly turbulent waters, extremely low-
velocities, or in areas or rapidly changing water-level, a longer period may be required. This
recommended sample time might vary from country to country and even within different organi-
zations.
The basic procedure for making a discharge measurement using the Stationary- Measurement
system is as follows:
1. Setting up the Location
•
A measurement section is selected based on the criteria outlined in Section G-5 below.
•
A graduated tag line is strung across the river. In an
ideal measurement site, the flow should be perpen-
dicular to the tag line at all points with no flow rever-
sals or obstructions. For ice measurements, a series
of holes (one for each station) are drilled in the ice.
•
The spacing of the stations along the tagline is se-
lected so as to provide about 20-30 stations. Each of
these stations should also be positioned so that no
station is expected to yield more than 10 % of the to-
tal discharge. Ideally, no station should have more
than 5% of the total discharge. This generally
means that the stations are not equally spaced but are instead spaced closely together
in deeper and high velocity areas and further apart in shallower and slower flowing are-
as.
Loc
0
Loc
1
Loc
2
Loc
3
Loc
4
Loc
5
Loc
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Loc
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Loc
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Loc
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Loc
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Loc
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Loc
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Dep
1
Dep
2
Dep
3
Dep
4
Dep
5
Dep
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Dep
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Dep
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Dep
9
Dep
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Dep
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Area
1
Area
2
Area
3
Area
4
Area
5
Area
6
Area
7
Area
8
Area
9
Area
10
Area
11
Station Location = Loc
Station Water Depth = Dep
Station Width = W = (Loc - Loc )/2 + (Loc - Loc )/2
Station Area = Area = W * Dep
Mean Station Velocity = V
Station Discharge = Q = Area * V
Total Discharge = Sum( Q )
i
i
i i+1 i i i-1
i i i
i
i i i
i
W
1
W
2
W
3
W
4
W
5
W
6
W
7
W
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W
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W
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W
11