A demonstration of the instream flow incremental methodology, Shenandoah River

Water-Resources Investigations Report 98-4157
Prepared in cooperation with the Lord Fairfax Planning District Commission, Virginia
By:  and 



Current and projected demands on the water resources of the Shenandoah River have increased concerns for the potential effect of these demands on the natural integrity of the Shenandoah River system. The Instream Flow Incremental Method (IFIM) process attempts to integrate concepts of water-supply planning, analytical hydraulic engineering models, and empirically derived habitat versus flow functions to address water-use and instream-flow issues and questions concerning life-stage specific effects on selected species and the general well being of aquatic biological populations.

The demonstration project also sets the stage for the identification and compilation of the major instream-flow issues in the Shenandoah River Basin, development of the required multidisciplinary technical team to conduct more detailed studies, and development of basin specific habitat and flow requirements for fish species, species assemblages, and various water uses in the Shenandoah River Basin. This report presents the results of an IFIM demonstration project, conducted on the main stem Shenandoah River in Virginia, during 1996 and 1997, using the Physical Habitat Simulation System (PHABSIM) model.

Output from PHABSIM is used to address the general flow requirements for water supply and recreation and habitat for selected life stages of several fish species. The model output is only a small part of the information necessary for effective decision making and management of river resources. The information by itself is usually insufficient for formulation of recommendations regarding instream-flow requirements. Additional information, for example, can be obtained by analysis of habitat time-series data, habitat duration data, and habitat bottlenecks. Alternative-flow analysis and habitat-duration curves are presented.

Suggested Citation

Zappia, Humbert, and Hayes, D.C., 1998, A demonstration of the instream flow incremental methodology, Shenandoah River, Virginia: U.S. Geological Survey Water-Resources Investigations Report 1998–4157, 24 p., https://pubs.er.usgs.gov/publication/wri984157.

Table of Contents

  • Abstract
  • Introduction
  • Description of the Shenandoah River Basin
  • Instream Flow Incremental Methodology (IFIM)
  • Application of the IFIM to the Shenandoah River
  • Simulation Results and Analysis
  • Summary and Conclusions
  • References Cited

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title A demonstration of the instream flow incremental methodology, Shenandoah River
Series title Water-Resources Investigations Report
Series number 98-4157
DOI 10.3133/wri984157
Year Published 1998
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Virginia Water Science Center
Description v, 24 p.
Online Only (Y/N) Y
Additional Online Files (Y/N) N