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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />reservoirs, and irrigation canals; and societal structures including streets, roads, highways, <br />railroads, bridges, culverts, dams, and buildings, Any other GIS data such as vegetation type and <br />cover, fences, power lines, property boundaries, and any other man made structures that are <br />available is beneficial, David Barnet, of Bristlecone GIS, provided ArcView GIS data that <br />included, but was not limited to, lakes, rivers, streams, contours, roads, and annexations. <br /> <br />The next field expedition was made on June 24th and 25th, 2002 by Tom Gilman and Gared <br />Grube, The purpose of this trip was to survey all of the necessary cross-sections, profiles that are <br />a necessary input to the completion of the hydraulic analysis. There are a number of different <br />techniques for surveying that can be used, Those techniques include the use of a level, a total <br />station, GPS equipment, or aerial surveying, The technique that was selected for this project was <br />using a survey grade GPS unit that had the capability of acquiring coordinates within centimeter <br />accuracy, GPS surveying was selected because it is less expensive than aerial surveying, less <br />time consuming than both using a level and a total station, the most accurate of the four <br />techniques, and the data can easily be imported into a GIS, <br /> <br />The specific unit used for surveying was TDS-Ashteck GPS survey equipment. This equipment <br />consisted of a Z-Xtreme GPS system and a TDS Ranger data collector. The Z-Xtreme (Figure <br />4), manufactured by Ashtech, is a weatherproof dual frequency GPS receiver that produces <br />centimeter accurate positions, An RTK base station (Figure 5), which is a component of the Z- <br />Xtreme package, is set up over a known point that differentially corrects the signal over that <br />point increasing the receiver's accuracy, The TDS Ranger data collector contains a 192 MHz <br />processor and 32 MB of RAM that allows many different capabilities and the storage oflarge <br />amounts of data, The TDS specifications can be found in Appendix A. The TDS Ranger <br />contains ports that connect directly to a computer and allows fast data transfers. <br /> <br />11 <br />