| Abstract: | The U.S. Geological Survey (USGS), in cooperation with the Colorado Water Conservation Board, the Upper Colorado River Endangered Fish Recovery Program (UCREFRP), Colorado Division of Water Resources, and City of Craig studied the gain-loss characteristics of Elkhead Creek downstream from Elkhead Reservoir to the confluence with the Yampa River during August through October 2009. Earlier qualitative interpretation of streamflow data downstream from the reservoir indicated that there could be a transit loss of nearly 10 percent. This potential loss could be a significant portion of the releases from Elkhead Reservoir requested by UCREFRP during late summer and early fall for improving critical habitat for endangered fish downstream in the Yampa River. Information on the gain-loss characteristics was needed for the effective management of the reservoir releases.
In order to determine streamflow gain-loss characteristics for Elkhead Creek, eight measurement sets were made at four strategic instream sites and at one diversion from August to early October 2009. An additional measurement set was made after the study period during low-flow conditions in November 2009. Streamflow measurements were made using an Acoustic Doppler Velocimeter to provide high accuracy and consistency, especially at low flows. During this study, streamflow ranged from about 5 cubic feet per second up to more than 90 cubic feet per second with step increments in between. Measurements were made at least 24 hours after a change in reservoir release (streamflow) during steady-state conditions.
The instantaneous streamflow measurements and the streamflow volume comparisons show the reach of Elkhead Creek immediately downstream from Elkhead Reservoir to the streamflow-gaging station 09246500, Elkhead Creek near Craig, CO, is neither a gaining nor losing reach. The instantaneous measurements immediately downstream from the dam and the combined measurements of Norvell ditch plus streamflow-gaging station 09246500 are mostly within the plus or minus 5-percent measurement error of each other. The variability of data is such that sometimes the streamflow is greater upstream than downstream and sometimes the streamflow is greater downstream than upstream. Streamflow volumes were calculated for multiple time periods as determined by a change in release from the reservoir. Streamflow volumes were greater downstream than upstream for all but one time period. The predominance of greater streamflows downstream is due to the difference between the USGS instantaneous measurements and record computation with the Supervisory Control and Data Acquisition (SCADA) record at the dam. Immediately following an increase in streamflow from the reservoir, the downstream volume was smaller than the upstream volume, but this was an artifact of the traveltime between the two sites and possibly small amounts of water entering the streambank. Traveltimes were shorter at higher streamflows and when streamflow was increasing. |
| Genre: | USGS Numbered Series |
| ProdID: | 98975 |
| Citation Author: | Ruddy, Barbara C. |
| Citation Contributing Office: | Colorado Water Science Center |
| Citation Datum: | |
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| Citation Edition: | - |
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| Citation Language: | ENGLISH |
| Citation Larger Work Title: | |
| Citation LatN: | 0403400 |
| Citation LatS: | 0403100 |
| Citation LonE: | -1072230 |
| Citation LonW: | -1072630 |
| Citation Month: | |
| Citation No Pagination: | N |
| Citation Number Of Pages: | |
| Citation Online Only Flag: | Y |
| Citation Phsyical Description: | iv, 14 p. |
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| Citation Public Comments: | Prepared in cooperation with the Colorado Water Conservation Board, Colorado River Water Conservation District, Upper Colorado River Endangered Fish Recovery Program, Colorado Division of Water Resources, and City of Craig |
| Citation Publisher: | U.S. Geological Survey |
| Citation Series: | Scientific Investigations Report |
| Citation Series Code: | SIR |
| Citation Series Number: | 2010-5198 |
| Citation Search Results Text: | Streamflow gain-loss characteristics of Elkhead Creek downstream from Elkhead Reservoir near Craig, Colorado, 2009; 2010; SIR; 2010-5198; Ruddy, Barbara C. |
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| Citation Volume: | |
| Citation Year: | 2010 |
| Type: | citation/reference |
| Text: | Streamflow gain-loss characteristics of Elkhead Creek downstream from Elkhead Reservoir near Craig, Colorado, 2009; 2010; SIR; 2010-5198; Ruddy, Barbara C. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/sir_2010_5198.bmp |
| URL (INDEX PAGE): | http://pubs.usgs.gov/sir/2010/5198/ |
| Date Other: | Fri, 31 Dec 2010 00:00 -0600 |
| Publisher: | U.S. Geological Survey |
