USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research Topics Water & Watersheds

Fine sediment in pools

V* is a measure of the supply of excess fine sediment (sand and fine gravel) in gravel bed channels. The method was developed in 1990 as part of our work on the effects of sediment on channel form.

Measuring the fraction of pool volume filled with fine sediment describes applications and limitations of the technique and how to measure V* in a pool and in a reach. Fine bed material in pools of natural gravel bed channels covers much of what we've learned about fine bed material and V* in the past nine years.

We have available here 'Lotus 123 v5' or 'Microsoft Excel' spreadsheets to calculate individual pool and reach mean water volume, fine sediment volume, and V*, and reach mean V* variance; instructions on using the spreadsheets; an example file; and notes on some potentially confusing pool measurement situations.


For calculating V* from pool measurement data. Download by clicking the link and using your browser to save to a file.

Lotus 123
  • vstar.wk4 -calculates pool and reach mean V*. Includes instructions and plots. Lotus 123 v5 or later.
  • fip.wk1 -a minimal, one pool spreadsheet we use on our palmtops. Includes random cross section locations for field use.
  • varv.wk1 -a single sheet to calculate reach mean V* and variance.
MS Excel
  • vstar1.xls -the Excel equivalent of vstar.wk4.
  • fip.xls -the Excel equivalent of fip.wk1.
  • varv.xls - the Excel equivalent of varv.wk1.

Instructions for Fip.wk1 and Varv.wk1, which also work for Fip.xls and Varv.xls

The instructions for vstar.WK4 are in the workbook, on the instructions sheet.

llm1999.wk1 is an example data file for a pool. To use it, copy all the cells with data in them starting at cell B1 (for the example sheet, that's B1-P30) and paste into starting at cell B1 or into vstar.WK4 starting at cell B4.

Notes describes some potentially confusing pool measurement situations and how we deal with them.