Document Details

The Instream Flow Incremental Methodology: A Primer for IFIM

U.S. Department of the Interior (DOI) | March 1st, 1995


This booklet is a primer on the Instream Flow Incremental Methodology (IFIM). Our objective for this primer is to give you a short but comprehensive introduction to the background, philosophical and ecological underpinnings, individual components, and steps in applying IFIM. As a primer, we have tried to keep it simple. Scientific names and other technical details have been avoided, but the primer includes relevant definitions (with key words or phrases indicated in italics for their first use), summaries of the literature where you may wish to turn for further reading, and explanations to increase your understanding of what IFIM is all about and how it works. The primer should reinforce your growing knowledge and provide the necessary stepping stones into more advanced, certified training in IFIM methods.

This primer is divided into five more or less independent sections. The first section reviews the history of instream flow problems in the United States. Reading this section should provide you with an understanding ofwhy IFIM emerged to solve certain complex water management problems and hint at future directions. The second section discusses the choice of instream flow methods and, more importantly, provides a framework for deciding whether IFIM is appropriate for the kind of problems you might be facing. The third section reviews the ecological underpinnings of IFIM from a historical perspective. This section is meant to show you the degree to which IFIM components, or models, represent the essence of the biological systems that we are attempting to understand. It is more detailed than the other sections and meant specifically to be of interest to biologists and ecologists. Section four delves into the broader philosophical, problem-solving approach embodied in IFIM.  This perspective is important because the ‘facts’ alone rarely dictate good decisions; it is how we employ those facts to resolve instream flow problems in an interdisciplinary decision making arena that is important. The fifth section outlines the logical steps in applying IFIM and the information flow that holds them together. Here you will learn how to navigate through the IFIM process from tentative problem identification to problem resolution.

Keywords

flows