to give consideration to uncertainty, attention is given primarily to uncertainties in parameter-sused in models for predicting future conditions and for the detailed design of facilities. Chapter 5 of this report describes approaches for addressing uncertainty.

Revising the Principles and Guidelines

The Principles and Guidelines should be reviewed and updated in order to reflect changes in social values since the early 1980s, as well as advances in analytical techniques and technologies. This recommendation to review and revise the Principles and Guidelines is consistent with the recommendation of a 1999 National Research Council committee charged to, among other things, review the state of the P&G. That committee recommended that the federal Principles and Guidelines “be thoroughly reviewed and modified to incorporate contemporary analytical techniques and changes in public values and federal agency programs ” (NRC, 1999a; see also NRC, 2000). The 1994 federal Interagency Floodplain Management Review Committee (IFMRC) report, also known as the Galloway Report (as the review committee was headed by Dr. Gerald E. Galloway, Jr.), contained a similar recommendation: “Principles and Guidelines should be revised to accommodate the new objectives and to ensure full consideration of nonstructural alternatives” (IFMRC, 1994). In revising the P&G, special attention should be given to: (1) guidance for incorporating concerns about environmental quality into plans for inland navigation systems, regardless of how the EQ objective is stated, (2) more definitive guidance on techniques for forecasting demands for waterway services over extended time horizons, and (3) more appropriate methods for treating uncertainty in large projects that are subject to high levels of uncertainty in future demand.

The P&G has provided useful planning guidance since it was approved in 1983, with much of that guidance still relevant and useful today. After 18 years of application, however, the P&G would be improved with a thorough review and the incorporation of modern water resources planning approaches and techniques.

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