PUBLICATIONS--TWRI, Book 7, Chapter C3, "A Model for Simulation of Flow in Singular and Interconnected Channels," In Reply Refer To: EGS-Mail Stop 415 October 8, 1981 SURFACE WATER BRANCH TECHNICAL MEMORANDUM NO. 82.03 Subject: PUBLICATIONS--TWRI, Book 7, Chapter C3, "A Model for Simulation of Flow in Singular and Interconnected Channels," by R. W. Schaffranek, R. A. Baltzer, and D. E. Goldberg Attached is a copy of the most recent chapter addition to the report series, Techniques of Water Resources Investigations (TWRI). This TWRI presents a digital-computer model for simulating one-dimensional flows occurring in a single reach of river channel or throughout a complex system of simply or multiply con- nected channels that are governed by time-dependent forcing functions and other boundary conditions. The report describes a model that is broadly applicable to a wide range of hydrologic conditions and field situations. While offering a thorough technical treatment of the model, the report is written in the style of a user's manual and is complete with several examples of actual implementation including one data set sufficient to permit trial utilization of the model. The model can be utilized for special-purpose, short-term simulations using card-input data, but is also fully supported by a disc-oriented, storage-and-retrieval system for conducting routine, longer-term discharge computations. In either mode the model provides the user with an array of optional graphical output capabilities. The model is a powerful, more accurate alternative to stage-fall or other slope- type rating techniques. It is particularly appropriate and cost effective for assessing flows in regulated rivers or in rivers where backwater effects are prevalent. As illustrative examples in the report show, the model is well suited for such diverse applications as singular upland river reaches in which unsteady flow results from hydropower regulations, coastal rivers composed of sequentially connected reaches subject to unsteady, tide-driven flow, and multiply connected networks of channels wherein flow may be governed by wind tides and seiches. Several new features, changes, and additional capabilities have been incorporated in the branch-network flow model during the months that the TWRI was in press. These are identified and documented in the attached memorandum from the authors. Please bring this TWRI to the attention of those personnel in your office who could possibly be involved in such surface-water flow assessments. Marshall E. Moss Acting Chief, Surface Water Branch 2 Attachments WRD Distribution: A, FO, SL "This memorandum does not supersede any existing SWB memorandum."