As part of the Long Term Ecological Research (LTER) project in the McMurdo Dry Valleys of Antarctica, a systematic sampling program has been undertaken to monitor the glacial meltwater streams in the region. Measurements are regularly made to examine water quality, quantity, and chemical properties. The stream gauge and outlet locations table serves as an index of the sampling points used to collect hydrological and stream chemistry data in the McMurdo Dry Valley network of streams. It documents the latitude, longitude and elevation of all the stream sample points used for hydrological and/or chemical analysis.
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Since streams are a critical link in the trophic interactions and biogeochemical cycles of the McMurdo Dry Valleys, streams located throughout the area were chosen for the long-term ecological research (LTER) study. To monitor stream hydrology, an extensive network of gauging stations was set up to continuously measure streamflow throughout the austral summers. Some streams are intermittently gauged to monitor water quality and quantity. While the researchers are in the field to collect hydrology data, stream water samples to be used for chemical analysis are also gathered. Sample locations for hydrology data thus coincides with those for stream chemistry samples. Locations also remain consistent from season to season. The coordinates (latitude, longitude and elevation) for many of these sites were measured with a GPS (global positioning system) gauge. Records based on the 1996-97 GPS measurements are accurate to about a meter. (They contain a value of "GPS96-97.DOC" for the 'file name' field). Other records may not have coordinates as precise as this. Most of them were obtained from a locations table created by Harry House (U.S Geological Survey). However, it is unknown what was initially used to measure these latitudes, longitudes and elevations. From time to time, samples are taken from sites that are not regularly monitored. When that occurs, the field team uses a GPS gauge, accurate to about 10 meters, to obtain the coordinates for the sample. The coordinates are then added to this dataset.
A 'locations' table was created by Harry House (USGS - Wisconsin office) in early 1994. It was first stored in an INGRES database, but was converted to ORACLE format in early 1996. Modifications were generally made each year after the initial creation in the early part of the year. It was transferred to INSTAAR in late 1997. In 1998, Denise Steigerwald (the McMurdo LTER data manager) received a report of "1996-97 MCM LTER GPS Coordinate Locations". This contained coordinates measured in the 1996-97 season that were accurate to about a meter. Records for stations that had less precise coordinates were therefore replaced. Comments were added to the 'descriptions' field where this occurred, and 'GPS96-97.DOC' was added to the 'file name' field (to show the file in which the values originated). In March, 2000, Denise Steigerwald added some variables to this file in order to make the dataset more useful in Oracle and GIS. These variables included dataset code, strmgageid, and stream.