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Groundwater Investigation and Associated Source Characterization
Appendix E - Survey Data
Notes on CSSA Well Surveys
October 1992 Northstar Land Surveying, San Antonio, Texas
In October 1992 Parsons ES retained Northstar Land Surveying to survey CSSA wells 1, 2, 3, 4, 5, 6, 9, 10, 11, 16, A, B, C, D, E, F, G, H, and I. Northstar provided northing and easting coordinates in Texas State Place Coordinates, South Central Zone, based on the North American Datum of 1983. Well casing and ground elevation measurements in feet were also provided. Northstar subcontracted the GPS survey work to Geodetix, San Antonio, Texas.
Attempts by Parsons ES to use Northstar Land Surveying coordinates proved difficult. The conversion necessary to incorporate surveyed positions into location maps would not provide corrected values. At the request of Parsons ES, Northstar Land Surveying subcontractor Geodetix provided conversions from NAD 83 (in meters) to NAD 27 (in feet) for wells 1, 2, 3, 4, 9, 10, 11, 16, D, G, H, and I.
January and April 1996 Macias & Associates, Inc. Land Surveyors, Austin, Texas
In January 1996 Macias & Associates surveyed and placed monuments at several GPS points on CSSA to ensure accurate reference for current and future survey work. They also surveyed points for the Blackhawk geophysical work, providing seismic line positional reference.
In April 1996 Macias & Associates performed additional surveys of wells 1, 2, 3, 4, 11, 16, and D. In addition, two monitoring wells installed in April 1996, MW-1 and MW-2, were surveyed. An error in elevation values was discovered and corrected by Macias & Associates. All Macias & Associates coordinates were provided in Texas State Place Coordinates, South Central Zone, based on the North American Datum of 1927. Macias & Associates subcontracted some work to Geodetix, San Antonio, Texas.