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<br />sediment bonds, bedform processes, bed armoring,
<br />and so forth combine to force recognition that mo-
<br />bile-bed models, especially l-D ones, must be
<br />thought of more as vehicles for gaining insight and
<br />gauging sensitivity than as absolute predictors.
<br />The Missouri River example points out the kind of
<br />insight and understanding that can be gained from
<br />such models, even if the absolute predictions must
<br />be treated with considerable caution.
<br />If a numerical mobile-bed modelling effort fails
<br />to live up to nominal expectations, it still repre-
<br />sents a productive expenditure of time and effort.
<br />The modelling effort itself, whether it involves
<br />just data assembly for an existing code or devel-
<br />opment of a code itself, forces the modeler into an
<br />intimate relationship with the river's topography,
<br />hydrology, sedimentology, and habitat, and their
<br />interactions. Out of this relationship and resul-
<br />tant insight grows the kind of balanced under-
<br />standing of the river and its ecosystem, and of
<br />their response to perturbations, which leads to
<br />informed river-development decisions reflecting
<br />the needs not only of man, but also of other life
<br />dependent on the riverine habitat.
<br />
<br />Cited Literature
<br />
<br />Fan, S. 1988. Twelve selected computer stream sedi-
<br />mentation models developed in the United States.
<br />Federal Energy Regulatory Commission, Washing-
<br />ton, D.C.
<br />Gessler, J. 1975. Stochastic aspects of incipient grain
<br />motion on river beds. Chapter 25 in H. W. Shen,
<br />editor, StoChastic approaches to water resources,
<br />Vol. II, Water Resource Publications, Ft. Collins,
<br />Colo.
<br />Harrison, A.S. 1950. Report on special investigations
<br />of bed sediment segregation in a degrading bed.
<br />University of California Institute of Engineering Re-
<br />search Report Series 33, Issue 1, Berkeley, Calif.
<br />Holly, F. M., Jr., and M. F. Karim 1986. Simulation of
<br />Missouri River bed degradation. Journal of Hydraulic
<br />Engineering 112(6):497-517.
<br />Holly, F. M., Jr., and M. F. Karim 1983. Computer
<br />simulation prognosis for the degradation of the Mis-
<br />souri River between Gavins Point Dam and Iowa's
<br />southern border. Iowa Institute of Hydraulic Re-
<br />search, University of Iowa, Iowa City Report 267.
<br />
<br />,
<br />
<br />FORREST M. HOlLY, JR. AND RoBERT ETI'EMA 425
<br />
<br />Holly, F. M., Jr., and J. L. Rahuel, 1989. New numeri-
<br />cal/physical framework for mobile-bed modelling
<br />Part I-Numerical and physical principles. Journal
<br />of Hydraulic Research, 27(4):401-416.
<br />Holly, F. M., Jr., M. Spasojevic, and Z. Zhang 1986.
<br />Simulation prognosis of the degradation of the Mis-
<br />souri River between Gavins Point Dam and Rulo
<br />Bridge. Iowa Institute of Hydraulic Research, Uni-
<br />versity of Iowa, Iowa City Report 312.
<br />Holly, F. M., Jr., J. C. Yang, P. Schwarz, J. Schaefer, S.
<br />H. Hsu, and R. Einhellig 1990. CHARIMA-numeri-
<br />cal simulation of unsteady water and sediment
<br />movement in multiple connected networks of mobile-
<br />bed channels. Iowa Institute of Hydraulic Research,
<br />University of Iowa, Iowa City Report 343.
<br />Karim, M. F., and J. F. Kennedy 1982. Computer-based
<br />predictors for sediment discharge and friction factor
<br />of alluvial streams. Iowa Institute of Hydraulic Re-
<br />search, University of Iowa, Iowa City Report 242.
<br />Krone, R. 1962. Flume studies of the transport of sedi-
<br />ment in estuarial shoaling processes. Hydraulic
<br />Engineering Lab, University of California, Berkeley.
<br />Lane, E. W. 1957. A study of the shape of channels
<br />fonned by natural streams flowing in erodible mate-
<br />rial. U.S. Army Corps of Engineers Missouri River
<br />Division Sediment Series 9, Omaha, Neb. Nebraska.
<br />Sayre, W. W., and J. F. Kennedy 1978. Degradation and
<br />aggradation of the Missouri River. Iowa Institute of
<br />Hydraulic Research, University of Iowa, Iowa City
<br />Report 215.
<br />Simons and Li Associates 1982. Engineering analysis of
<br />fluvial systems, Fort Collins, Colo.
<br />Simons, D. B., and E. V. Richardson. 1966. Resistance of
<br />flow in alluvial channels. U.S. Geological Survey Pro-
<br />fessional Paper 422J, Washington, D.C.
<br />Spasojevic, M., and F. M. Holly, Jr. 1990. 2-D bed evolu-
<br />tion in natural watercourses-new simulation ap-
<br />proach. Journal of Waterway, Port, Coastal, and
<br />Ocean Engineering 116(WW4):424-443.
<br />Thomas, W. A., and W. H. McAnally, Jr. 1985. User's
<br />manual for the generalized computer program sys-
<br />tem open channel flow and sedimentation-TABS-2.
<br />U.S. Army Corps of Engineers Waterways Experi-
<br />ment Station Hydraulics Laboratory Instruction re-
<br />port HL-85-1. Vicksburg, Miss.
<br />van Rijll, L.C. 1984. Sediment transport, Part II: sus-
<br />pended load transport. Journal of Hydraulic Engi-
<br />neering 110(11):1613-1641.
<br />Vanoni, V., editor. 1975. Sedimentation engineering.
<br />ASCE Manual 54, ASCE, New York.
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