1400 ‎(2)‎

• UCREFRP Catalog Number: 1400
• Author: Simons, D. B., et al., ed.
• Title: Proceedings
• USFW Year: 1980.
• USFW - Doc Type: Workshop on Downstream River Channel Changes Resulting From Diversions or Reservoir Construction.
• Copyright Material: NO

THE PROBLEMS 1

YAMPA RIVER

The Yampa River is located in northwestern Colorado. The river is
essentially a gravel-cobble bed stream above the confluence with the
Little Snake River. Below the confluence the river is predominantly a
sand-bed stream. Several reservoi rs are proposed to be constructed on
the Yampa River; one is the proposed Cross Mountain Reservoir and another
is the proposed Juniper Reservoir. These reservoirs will impose changes
in the flow and sediment regime of the river which will, in turn, cause
possible alterations in the channel morphology.

The objective of this workshop problem was to discuss the short and
long term changes of the following stream characteristics of the Yampa
River as a resu.lt or the two reservoirs as follows:

1. Meander pattern
2. Confi gurat i on of the channe 1,
3. Substrate material, and
4. Pool-riffle sequence.

Data supplied by the U.S. Fish and Wildlife Service include infor-
mation on four small reaches of the river, but only two are to be
considered in any detail: the Box Elder reach and the lily Park reach.
Lily Park reach is located just above the Little Snake River, and Box
Elder reach is located just above the juncton of the Yampa River with
the Green River.

POPLAR CREEK

Poplar Creek (not the stream's true name) is a sand and gravel bed
stream located in northern California. It is a tributary to the
Sacramento River. Precipitation ranges from 70 inches in the headwaters
to between 25 and 30 inches in the reach of interest below the proposed
Dutch Gulch dam site. For purposes of discussion the reach of concern
can be divided into two reaches as follows: Reach 1 between the dam and
the junction of a major tributary, Dry Creek; and Reach 2 below the
junction of Dry Creek. Participants were asked: "What will happen to
the morphology of the stream's channel as a resul t of the changes in
streamflows and sediment discharge caused by the construction of a
reservoi r upstream of a reach of stream?" Speci fica lly, for both a
short and a long time after construction of the reservoir:

lFor purposes of the Workshop the physical characteristics of the three
river systems were simplified and altered to a degree. Because of this
"academic 1 icense," the results of the Workshop should not be interpreted
as representative of the response to be anticipated if the proposed
development were to be implemented.

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