YSI SonTek RiverSurveyor, System Manual

Page: 70 / 194

SonTek/YSI Inc
RiverSurveyor System Manual (May 1, 2007)
58
4.2. Computer Modeling and Verification
The following topics are covered in this section:
•
Does RiverSurveyor work with Computer Models?
•
How does RiverSurveyor work with 2-D Computer Models?
•
How does RiverSurveyor work with 3-D Computer Models?
4.2.1. Does RiverSurveyor work with Computer Models?
Hydrological computer modeling generally involves the simulation of hydrodynamic mecha-
nisms and processes in rivers, streams, and canals, including the groundwater and other external
influences. The purpose of computer modeling is to predict (or simulate) upcoming hydrody-
namic events and effects, and to forecast any changes that could occur to the environment.
Typically, computer modeling of rivers and streams involves the use of two-dimensional (assum-
ing either lateral or vertical homogeneity) or three-dimensional computer models. SonTek’s
software is designed to provide input into both these types of models. Data files that can be input
into the model can be exported from either
RiverSurveyor or ViewADP programs.
4.2.2. How does RiverSurveyor work with 2-D Computer Models?
For 2-D models, RiverSurveyor can output depth-averaged velocity data across the measured
transect. This data can be used for direct input into the model or comparison with simulated data.
To output 2-D current velocity data from RiverSurveyor , select
File|Export Data|Export Single
Discharge Measurement
. A data file containing positional and depth-averaged current informa-
tion will be created using the file name and path you select. This file will have the Discharge
Data File format described in Appendix
B-2.1
.
4.2.3. How does RiverSurveyor work with 3-D Computer Models?
For 3-D models, initial data comparisons should be against two-dimensional data to get a good
understanding of whether the simulated data is matching the general trends of the collected data.
2-D data output was described above (§
4.2.2
). The output of 3-D current velocity data is best
achieved through our ViewADP program, which is included with every RiverSurveyor system.
To output 3-D current velocity data from ViewADP , select
File|Export Data
from the menu. The
ASCII File Output
dialog box will be displayed (
Figure 4-7
). You can then select from several ex-
port options. Each export option uses a different file format, which is described in the ADP Op-
eration Manual that was included with your RiverSurveyor system.
We suggest that before you export the data:
•
You set
Processing|Velocity Reference
to
Bottom Track
.
•
You filter out all invalid cell data using the
Processing|Data Screening
option to enable the
Pressure/BTrack/Range to Bottom
filter option. This will use the bottom-track information
to discard any water current velocity data below the riverbed.
To combine 3-D water current data with positional data will require the integration of either the
velocity component or speed/direction data (from GPS or bottom-track data) using a third-party
software program such as Microsoft
®
Excel or MATLAB
®
.