Filters: Tags: Lake Powell (X) > Types: Citation (X)
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In the spring of 1996, a nine-day test flood from Glen Canyon Dam involved the deepest and largest hypolimnetic withdrawals from the penstocks and the river outlet works (ROW) since 1986, interacting with ongoing hydrodynamic and stratification patterns to enhance freshening of the hypolimnion of Lake Powell reservoir and its tailwaters. Prior to the test flood, a six-year drought had produced a pronounced meromictic hypolimnion that was weakening from high inflow events in 1993 and 1995. Hypoxia, however, had continued to increase in the deepest portions of the reservoir. Over the course of the test flood, 0.893 km3 were released from the ports located at and below the hypolimnetic chemocline. The increased discharge...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Colorado River,
Ecological Applications,
Glen Canyon Dam,
Lake Powell,
dam operations,
A selenium budget for Lake Powell, Utah-Arizona was determined based on selenium loads at the principal stream input sites to and the output site from the lake. Based on data collected during 1985-1994, 83 percent of the selenium entering Lake Powell is accounted for at the output site. The rest of the selenium may be incorporated by lake sediment or used by the biota. Considerably more selenium per unit area is produced from the Colorado River Basin above the Colorado River-Green River confluence than from the Green River Basin and the San Juan River Basin combined. The Gunnison River Basin and the Grand Valley in Colorado produce an estimated 31 and 30 percent of the selenium that reaches Lake Powell, respectively....
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Colorado River Basin,
Journal of the American Water Resources Association,
Lake Powell,
irrigation,
selenium
These data are classified maps of water in the Colorado River at a discharge of approximately 227 meters squared/second in Grand Canyon from Glen Canyon Dam to Pearce Ferry in Arizona. The data are derived from interpretation of multispectral high resolution airborne imagery that was acquired in May 2013. The water classification data have the same 0.2-meter ground resolution as the imagery. These data have not undergone a statistical accuracy assessment, but they are based on methods that included image interpretation to exhaustively identify water which have been shown to produce very high classification accuracies and excellent correlation between maps of total vegetation produced by independent analysts and...
In May 2013, the Grand Canyon Monitoring and Research Center (GCMRC) of the U.S. Geological Survey’s (USGS) Southwest Biological Science Center (SBSC) acquired airborne multispectral high resolution data for the Colorado River in Grand Canyon in Arizona, USA. The imagery data consist of four bands (blue, green, red and near infrared) with a ground resolution of 20 centimeters (cm). These data are available to the public as 16-bit geotiff files. They are projected in the State Plane (SP) map projection using the central Arizona zone (202) and the North American Datum of 1983 (NAD83). The assessed accuracy for these data is based on 91 Ground Control Points (GCPs), and is reported at 95% confidence as 0.64 meters...
This paper presents data analyses based on information gathered from a recreation survey distributed during the spring of 1997 at Lake Powell. Recreation-linked management issues are the foci of the survey and this discussion. Survey responses to contingent valuation method (CVM) queries included in the questionnaire quantify visitor recreation values. The CVM estimates of the benefits provided by potential resource improvements are compared with the costs of the improvements in a benefit-cost analysis. The CVM questions covered three resources management issues including water quality improvement, sport fish harvest enhancement, and archeological site protection and restoration. The estimated benefits are remarkably...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Lake Powell,
Water International,
contingent valuation,
logistic,
probit
These data are classification maps of total riparian vegetation along the Colorado River in Grand Canyon from Glen Canyon Dam to Pearce Ferry in Arizona. The data are derived from interpretation of multispectral high resolution airborne imagery that was acquired in May 2013. The total vegetation data have the same 0.2-meter ground resolution as the imagery. These data have not undergone a statistical accuracy assessment, but they are based on methods that included image interpretation to exhaustively identify total vegetation which have been shown to produce very high classification accuracies and excellent correlation between maps of total vegetation produced by independent analysts and ground truth. The data represent...
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