8246 - Laserfiche WebLink

Home Browse Search

1 correlation was also established for an 1 1-yr period of overlapping records for the gages near Linwood and at Green River, WY, between 1929 and 1939. This record has an r2 value of 0.900 and was used to extend the Linwood record, and thus the Greendale record, to 1895. A similar procedure was used to extend the Jensen record. In this case, however, the flood records of three gages - Green River near Linwood, Little Snake River near j Lily, CO, and the Yampa River near Maybell, CO - were analyzed. Peak flows at Jensen are the combination of either the peak Yampa flood at a time of high Green River discharge or a peak Green River flood at a time of high Yampa River discharge. Because the Little Snake record begins in 1923, the Jensen record could not be extended earlier than this date. Records for Colorado River at Cisco, UT (09180500), Green River at Green River, UT (09315000) , Colorado River at Lees Ferry, AZ (09380000), and Colorado River near Grand Canyon, AZ (09402500), were evaluated using measured values. Analysis of U.S. Geological Survey Stream Gaging Notes (Appendix B) Maintenance of stream gaging stations requires that discharge measurements be made approximately monthly. These measurements involve the measurement of velocity and depth at approximately 20 sites along a cross-section. Each of these measurements is made relative to the water surface; the absolute elevation of the cross-section can be d t i d b e erm ne ecause the gage height at the time of measurement is also recorded. These data can be analyzed to determine (1) long-term changes in bed elevation and channel width, and (2) the long-term relationship between discharge and width, depth, and velocity (known as hydraulic geometry). The former data are critical to evaluating bed aggradation and degradation, and the latter data are useful in the development of flow or transport models. Three gaging stations -- Greendale, Jensen, and Ouray (09307000)-- have been analyzed. Analysis is preceded by (1) copying every gaging measurment note, and (2) entering relevant data into a data base. We have received significant cooperation fro th U S G l i l S m e eo . . og ca urvey Water Resources Division Utah State office in this effort. In many cases, records have been recalled from archives or from field stations. Because there are hundreds of notes, substantial effort has gone into simply obtaining, copying, and entering the data. Data included in Appendix B are (1) time series plots of changes in mean elevation of the bed elevation of the thalwe and to g, p width, (2) representative cross- t