The High Plains Regional Ground-Water Study encompasses an area of 174,000 square miles in eight States and is the largest study unit of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program. Geographic Information System (GIS) software is being used in the study to organize, analyze, and display geographic information for this large area. The ArcView 3-D Analyst¹ is an especially useful GIS tool for this study because the focus of the study is a three-dimensional object--the High Plains aquifer. The 3-D Analyst is being used for quality assurance of data; for example, to compare tabulated well characteristics (such as well depth, water level, and contributing aquifer) with independently derived three-dimensional aquifer-characteristics data sets. The 3-D Analyst also is being used for tasks which require visualization of aquifer morphology and characteristics; for example, to assist in the determination of the optimum placement of new monitoring wells. Finally, the 3-D Analyst is being used for data analysis; for example, to create and display water-quality-concentration surfaces that can be compared with each other and with aquifer characteristics.

¹Use of trade names is for identification purposes only and does not imply endorsement by the U.S. Geological Survey.