Sampling Strategies for Mass‐Discharge Estimation
Publication: Journal of Environmental Engineering
Volume 109, Issue 4
Abstract
Methodology derived from sampling theory is presented for the estimation of in‐stream contaminant mass‐discharge or load. The historical record is stratified into relatively homogeneous units in order to approach normality in the subpopulations thereby reducing the inaccuracies introduced by the highly skewed populations. Within strata a ratio estimator is employed to estimate the load and variance of the subpopulations. Strata are also defined to minimize other forms of inaccuracy. Estimates for individual strata are combined to produce pooled estimates for the desired period of interest. With a prior data base, sampling theory is employed to devise sampling strategies designed to produce load estimates of a specified target precision in future studies. Case studies demonstrate the significance of flow events as the primary transport mechanism for suspended sediment and the need to sample such events intensively in order to achieve reliable load estimates. Small “flashy” streams require sampling of much greater intensity during events than larger rivers with attenuated event response in order to produce load estimates of comparable precision.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Cochran, W. G., Sampling Techniques, 2nd ed., John Wiley and Sons, Inc., New York, N.Y., 1963.
2.
Hore, R. C., and Ostry, R. C., “Grand River, Ontario, Summary Pilot Watershed Report,” Report to PLUARG Task Group C, International Joint Commission, Windsor, Ontario, Canada, Apr., 1978.
3.
“International Reference Group on Great Lakes Pollution from Land Use Activities,” Quality Control Handbook for Pilot Watershed Studies, International Commission, Windsor, Ontario, Canada, Mar., 1977.
4.
Kendall, M. G., and Stuart, A., The Advanced Theory of Statistics, Vol. 3, 2nd ed., Hafner Publishing Company, Inc., New York, N.Y., 1968.
5.
Ongley, E. D., Ralstron, J. G., and Thomas, R. L., “Sediment and Nutrient Loadings to Lake Ontario: Methodological Arguments,” Canadian Journal of Earth Sciences, Vol. 14, 1977, pp. 1555–1565.
6.
Tin, M., “Comparison of Some Ratio Estimators,” Journal of the American Statistical Association, Vol. 60, 1965, pp. 294–307.
7.
Verhof, F. H., Yaksich, S. M., and Melfi, D. A., “River Nutrient and Chemical Transport Estimation,” Journal of the Environmental Engineering Division, ASCE, Vol. 106, No. 3, June, 1980, pp. 591–608.
8.
Walling, D. E., “Assessing the Accuracy of Suspended Sediment Rating Curves for a Small Basin,” Water Resources Research, Vol. 13, No. 3, 1977, pp. 531–538.
9.
Ward, R. C., Loftus, J. C., Nielsen, K. S., and Anderson, R. D., “Statistical Evaluation of Sampling Frequencies in Monitoring Networks,” Journal of the Water Pollution Control Federation, Vol. 51, No. 9, 1979, pp. 2292–2300.
10.
Weber, H., Cluis, D., and Bobee, B., “Accuracy Evaluation in the Calculation of Mass‐Discharge,” Journal of Hydrology, Vol. 40, No. 1/2, 1979, pp. 175–184.
Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 109 • Issue 4 • August 1983
Pages: 812 - 829
Copyright
Copyright © 1983 ASCE.
History
Published online: Aug 1, 1983
Published in print: Aug 1983
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.