Pacific Northwest Research Station

Title: A new method for reporting and interpreting textural composition of spawning gravel.

Author: Lotspeich, Fredrick B.; Everest, Fred H.

Date: 1981

Source: Res. Note PNW-RN-369. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 11 p

Station ID: RN-PNW-369

Description: A new method has been developed for collecting, sorting, and interpreting gravel quality. Samples are collected with a tri-tube freeze-core device and dry-sorted by using sieves based on the Wentworth scale. An index to the quality of gravel is obtained by dividing geometric mean particle size by the sorting coefficient (a measure of the distribution of grain sizes) of a sample. The resulting number is called the "fredle index" and is proposed as a standard for evaluating the reproductive potential of spawning gravel.

Keywords: Spawning beds, gravels, sediment sampling, stream habitat management, indexes (spawning gravel), fish habitat

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Citation

Lotspeich, Fredrick B.; Everest, Fred H.  1981.  A new method for reporting and interpreting textural composition of spawning gravel..   Res. Note PNW-RN-369. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 11 p