7930

• UCREFRP Catalog Number: 7930
• Author: Ketcheson, G. L.
• Title: Sediment Rating Equations
• USFW Year: 1986.
• USFW - Doc Type: An Evaluation for Streams in the Idaho Batholith.
• Copyright Material: NO

THE AUTHOR
GARY L. KETCHESON served as a hydrologist at the
Forestry Sciences Laboratory, Boise, ID, at the time
this work was completed. He held a technology trans-
fer position sponsored by the Intermountain Research
Station and the Northern and Intermountain Regions
of the USDA Forest Service. He conducted erosion and
sedimentation studies and prepared documents to
assist the dissemination of research findings to prac-
ticing forest hydrologists. He is currently the forest
hydrologist on the Sawtooth National Forest, Twin
Falls, ID. He holds a B.S. degree in resource conserva-
tion from the University of Montana and an M.S.
degree in forest hydrology from Oregon State Univer-
sity, which he received in 1976 and 1978 respectively.
RESEARCH SUMMARY
Sediment data collected on streams from National
Forests and a watershed research study area in the
Idaho batholith were used to develop suspended, bed-
load, and total sediment rating equations. This report
discusses the statistics associated with 125 sus-
pended, 121 bedload, and 119 total sediment rating
equations. For streams where the timing and amount
of management activities within the watershed were
documented, any shifts in rating equations were com-
pared with the timing of these activities. Some shifts
in rating equations coincided with the occurrence of
management activities while others did not.
Sediment yields were estimated using rating equa-
tions and a time-integration technique for data from
the Boise National Forest. The two methods gave sig-
nificantly different estimates of total annual sediment
yield. For the research data the same predictions were
made and compared with estimated sediment yield
from sediment dams at the mouths of the drainages.
The rating equation and time-integration techniques
estimated similar sediment yields that were also simi-
lar to those from the sediment dams. However, the
time-integration estimates more closely matched those
from the sediment dams.
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