Use of the Global Positioning System to Aid in Environmental Studies

Celeste Barry, Patrick O’Callaghan, Noriko Kawamoto and David Stensby

Abstract:	Over the past half decade, on projects from the San Francisco Bay in California to Hartwell Lake in South Carolina, Bechtel has successfully used the GPS to expeditiously execute environmental characterization and remediation activities in both aquatic and terrestrial environments. This paper will focus on use of the GPS technology for environmental studies. Due to the nature of environmental remediation, specific site locations and client names must remain confidential, but the following is a brief overview of the types of projects where Bechtel has utilized GPS technology. These efforts have resulted in great time and cost savings over conventional surveying techniques. Bechtel has utilized a variety of GPS receivers with increasing sophistication in achievable accuracies and differential capabilities ranging from post- processing data (3 - 5 m accuracy) in 1991 to real- time correction (less than 1 m accuracy) in 1993. In the early 1990’s, prior to the availability of a completed 24 satellite GPS constellation, Bechtel used the technology to identify sample coordinates and aid in delineation of contaminant boundaries. Planning around windows of visibility was critical to the success of these projects. In a two-phase study from 1991 through 1992, Bechtel utilized differential GPS to locate over 320 sediment sample locations on Hartwell Lake, a 56,000-acre reservoir. These sediment samples were used to trace the distribution of PCB contamination originating from a discharge point some 24 miles upstream of the lake. In 1992, at a site in the western United States, GPS technology was used to locate over 100 soil sampling coordinates at locations scattered within a 4 mile radius of the contaminant source area, and then later return to sample locations for additional characterization of suspect areas. After completion of the GPS satellite constellation and the availability of worldwide 24-hour GPS coverage in 1994, Bechtel used upgraded receivers (achieving accuracies of less than 1 m). GPS was used at one jobsite to conduct a walkover survey and delineate surface radiation in a forested recreational area once utilized for the nation’s early atomic energy program during the 1940’s. Another site located within the Great Lakes system utilized GPS to verify locations of sediment contamination under 35 ft. of water. Also during this time period, GPS was utilized on the west coast of the United States in the San Francisco Bay to locate sampling stations used to evaluate localized bottom habitat variations within the hydrologic influence of an active disposal site. Over the next five years, Becthel plans to increase its use of both stationary and kinematic GPS to locate samples at additional environmental sites. GPS may be used to initially establish site boundaries and aid in rapid characterization of several smaller former Manhattan project waste sites scattered throughout the eastern United States. GPS is also in the planning stages to assist in characterization of waste areas and verify cleanup levels at a facility on the west coast. Due to the enormous size of this site, a fleet of up to 10 roving vehicles, equipped with GPS receivers is planned for initial characterization activities. The simultaneous use of GPS capabilities will allow for quicker delineation and ultimate remediation. Presenting the successful use and cost savings of the GPS as a tool for environmental remediation will raise the awareness of profressionals in environmental fields across the United States and standardize as well as expand its future use.
Published in:	Proceedings of the 51st Annual Meeting of The Institute of Navigation (1995) June 5 - 7, 1995 Antlers Doubletree Hotel Colorado Springs, CO
Pages:	467 - 473
Cite this article:	Barry, Celeste, O’Callaghan, Patrick, Kawamoto, Noriko, Stensby, David, "Use of the Global Positioning System to Aid in Environmental Studies," Proceedings of the 51st Annual Meeting of The Institute of Navigation (1995), Colorado Springs, CO, June 1995, pp. 467-473.
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