WSP01244

• File Number: 8240.200.10.B
• Description: UCRBRIP Annual Report
• Basin: Colorado Mainstem
• Date: 4/9/2003
• Author: UCRBRIP
• Title: 2002 Annual Reports Package Part 1
• Water Supply Pro - Doc Type: Publication

COLORADO RIVER RECOVERY PROGRAM
FY 2002 ANNUAL PROJECT REPORT

RECOVERY PROGRAM
PROJECT NUMBER: 85B

1.

Project Title: Green and Yampa River Basin Sediment Monitoring Program

II.

Principal Investigator:
John G. Elliott
U.S. Geological Survey
E-mail: [e-mail]
Phone: [phone] ex 296
Fax: [phone]

III.

Project Summary:

)

The Recovery Program has identified a need to better define the requirements,
appropriate methodologies, and levels of effort for a sediment monitoring program, to
help define habitat requirements for endangered fishes in the Yampa, Little Snake, and
Green rivers. To meet that need, an independent peer review panel was formed to review
historical data, review the status of ongoing data collection efforts, identify sediment
issues as they relate to recovery of endangered fishes, and develop recommendations for
future sediment study to support Recovery Program efforts. The water resources of the
Upper Colorado River Basin have been extensively developed for water supply,
irrigation, and power generation through water storage in upstream reservoirs during
spring runoff fuid subsequent releases during the remainder of the year. The net effect of
water-resource development has been to significantly modify the pre development annual
hydrograph as well as the timing and amount of sediment delivery from the upper Green
River and the Yampa River Basins tributaries to the main-stem reaches where endangered
native fish populations have.been observed. This study identifies sediment source
reaches in the Green River mainstem and the lower Yampa and Little Snake rivers. The
study also provides sediment and streamflow, data and sediment-transport relations that
will be useful. in assessing the potential effects of hydro graph modification by reservoir
operation on sedimentation at identified razorback spawning bars in the Green River.
The need for additional data collection is evaluated at each sampling site.

Sediment loads were calculated at five key areas within the watershed by using
instantaneous measurements of streamflow, suspended-sediment concentration, and
bedload. Sediment loads were computed at each site for two modes of transport
(suspended load and bedload) as well as the total sediment load (suspended load plus
bedload) where both modes were sampled. Sediment loads also were calculated for silt-
and-clay, and sand-and-gravel sizes by hydrograph season. Sediment-transport curves
were developed for each type of sediment load by a least-squares regression of
logarithmic-transformed data.

Transport equations for suspended load and total load had coetlicients of determination of
at least 0.75 at all of the sampling sites except Little Snake River near Lily, Colorado
where the coefficient of determination for suspended load was 0.73 and where no bedload

85 B-1