9568

• UCREFRP Catalog Number: 9568
• Author: Resource Consultants Inc.
• Title: Sediment Transport Studies of the Little Snake, Yampa, and Green River Systems.
• USFW Year: 1991.
• USFW - Doc Type: Fort Collins, CO.
• Copyright Material: NO

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DISCHARGE, CFS
6,000

LITTLE SNAKE RIVER

5,000 .......................................................................................................................................................................

* Rei MEASURMENT
4,000 .......................................................................................................................................................................

3,000 .......................................................................................................................................................................

2,000 .......................................................................................................................................................................

o
MAR

1,000 ....................................................... ..... .... .. ..............................................................................................

APR

MAY

JUNE
DATE

JUL

AUG

Figure 3.5 1989 Runoff season hydrograph at Dixon.

The three sampling periods completed in 1989 were May 24-26, June 5-7 and June 23.25. A late
start on the stream gaging effort did not allow measurement on the rising limb, or near peak flow, but did
include a relatively wide range of recession flows. Note that the telemetry data for the Dixon and Lily
gages was adopted on the first two trips (5/24 and 6/06), and only on the third trip were these sites gaged.

The data collected were found to be in good agreement with USGS data taken during the same
runoff period. The stream gaging results at Lily on 6/24/89 are plotted with the preliminary USGS flow
record in Fig. 3.5 showing favorable comparison. Gaged data at Juniper Hot Springs bridge, located
slightly upstream of the Maybell gage, are plotted on the Maybell hydrograph (Fig. 3.3) and also agree well.
These results conftrm the sampling and data reduction techniques and provide confidence in the resulting
stream flow measurements.

35 Sediment Transport Data

Sediment measurements were made with suspended load samplers and Helley-Smith bedload
samplers (see Section 3.3.2). Note that the Helley-Smith sampler does capture near bed suspended
sediment greater than 0.25 mm, thus the sample results are not strictly synonymous with bedload. For
practical purposes, the sum of the suspended sediment load (based on the measured zone concentration
and total flow rate) and the Helley-Smith load may be considered as the total sediment (tons/day).
However, in a precise interpretation this procedure results in a double counting of portions of the near bed
suspended sediment. Given the natural variability of sediment movement and the accuracy of sediment
transport measurement, this problem was not considered significant and no correction was attempted.

The results from the sediment and stream gaging efforts are summarized in Table 3.1. The table
consists of water discharge, suspended sediment, Helley-Smith, and an estimate of bed material load. The
water discharge (ColI) was measured during stream gaging for all but four flows which were determined

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