Conclusions
This technical note has demonstrated statistical techniques for verifying the representativeness
of fixed monitoring systems that monitor mean values of parameters in flowing water. These
techniques were illustrated with data collected on the Columbia and Snake Rivers. Based on the
criteria detailed in this technical note, a preliminary analysis of the 1995 Columbia and Snake
Rivers fixed monitor system data set revealed that none of the fixed monitor systems accurately
represented the average river total dissolved gas concentrations. This demonstration was,
however, based on limited transect data, which were not specifically collected for the purposes
of monitor site verification.
These examples given in this technical note illustrate use of the statistical approach to
eliminate the subjectiveness involved in determining whether a monitoring station accurately
represents the water quality in a river. The information presented can be used to guide managers
to the most problematic locations, so improvements can be made on a "worst-case first" basis.
Additionally, pilot studies similar to the ones used to collect the data used in this technical note
can be used to help design verification studies to control the power of the test, obtaining the
desired trust in the results.
Many other factors, such as cost, ease of accessibility, and equipment availability, contribute
to the difficulties in monitor system design and installation. The cost of an intensive analysis
like the ones described above may be prohibitive to many water quality managers. However, the
ideas presented herein should make the manager more aware of the difficulties involved in
collecting representative data and improve the final system design.
References
Gaugush, R. F., tech. ed. (1986). "Statistical methods for reservoir water quality investigations,"
Instruction Report E-86-2, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.
Hines, W. W., and Montgomery, D. C. (1980). Probability and statistics in engineering and
management science. John Wiley and Sons, New York, 291-93.
Lemons, J. W., Vorwerk, M. C., and Carroll, J. H. (1996). "Remote monitoring of total dissolved
gas: Design, installation, and verification of remote monitoring systems," Water Quality '96,
Proceedings of the 11th Seminar, Miscellaneous Paper W-96-1, U.S. Army Engineer Waterways
Experiment Station, Vicksburg, MS.
Lemons, J. W., Vorwerk, M. C., Jabour, W. E., and Carroll, J. H. (1996). "Remote downstream
monitoring of Savannah River hydropower releases," Miscellaneous Paper EL-96-5, U.S. Army
Engineer Waterways Experiment Station, Vicksburg, MS.
Pollard, J. H. (1977). A handbook of numerical and statistical techniques. Cambridge University
Press, Cambridge, 177-79.
Vorwerk, M. C., and Carroll, J. H. (1994). "Implications of reservoir release and tailwater monitor
placement," Lake and Reservoir Management 9(1),172-78.
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Water Quality Technical Note AM-03 (January 1998)
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