7087

• UCREFRP Catalog Number: 7087
• Author: Elliot, J. G., J. E. Kircher and P. V. Guerard.
• Title: Sediment Transport in the Lower Yampa River, Northwestern Colorado.
• USFW Year: 1984.
• USFW - Doc Type: Denver, CO.
• Copyright Material: NO

SEDIMENT TRANSPORT IN THE LOWER YAMPA RIVER,
NORTHWESTERN COLORADO
By John G. Elliott, James E. Kircher, and Paul Von Guerard
ABSTRACT
Discharge measurements and sediment samples were taken at streamflow-
gaging station 09260050 Yampa River at Deerlodge Park in 1982 and 1983 to
determine the average annual sediment supply to the Yampa Canyon in Dinosaur
National Monument. Daily mean discharge recorded at the Deerlodge Park gage
correlated well with the sum of daily mean discharges recorded at two
streamflow-gaging stations in the drainage basin upstream: Station 09251000
Yampa River near Maybell, and station 09260000 Little Snake River near Lily.
Because of good correlation of discharges recorded during the study period
(R2=0.98), 43 years of discharge records at the two tributary sites were
combined to determine the historic discharge of the Yampa River at Deerlodge
Park. An historic average hydrograph and a flow-duration curve were derived
from the combined discharge data,
Sediment-transport equations were derived for total sediment discharge,
suspended-sediment discharge, bedload discharge, and the discharge of sediment
in several particle size ranges. Annual sediment discharges were determined
by the flow-duration, sediment-rating-curve method. These computations
indicated that mean annual total sediment discharge was approximately 2.0
million tons per year of which 0.8 million tons per year was sand size materi-
al. Bedload was almost entirely sand, and mean annual bedload discharge was
_,0.1 million tons per year.
Development of water resources in the Yampa River basin could have
considerable effect on the geomorphic and biological character of the Yampa
River at Deerlodge Park and through the Yampa Canyon. In this report, several
scenarios of altered streamflow frequency distribution, reduced streamflow
volume, and reduced sediment supply are examined to estimate the effect on the
sediment budget at Deerlodge Park.
INTRODIiCTION
Channel morphology as well as the aquatic and riparian habitat of the
Yampa River in Dinosaur National Monument is primarily controlled by the
prevailing streamfilow regime and transported sediment. The river channel will
adjust to significant long-term changes in the total volume of annual
streamflow, the range of discharge, the sediment supply, or the particle size
of sediment. Water resource development in the Yampa River basin could lead
1