Date of Graduation

7-2021

Document Type

Thesis

Degree Name

Master of Science in Geography (MS)

Degree Level

Graduate

Department

Geosciences

Advisor

Jason Tullis

Committee Member

Fred Limp Jr.

Second Committee Member

John Burnham Shaw

Keywords

Contour maps, Drone mapping, Drones, Geodesy, Geography, Geolocation

Abstract

Groundwater monitoring wells are commonly installed on a property as part of an environmental investigation to observe hydrological subsurface conditions, facilitate the collection of groundwater samples, and predict the flow of groundwater across a site. In addition to their installation, monitoring wells should be surveyed or mapped as accurately as possible. Traditional surveying techniques have employed the use of global navigation satellite systems (GNSS) technologies or other surveying equipment. A common surveying approach is to use real-time kinematic (RTK) GNSS to accurately measure the coordinates of each monitoring well on the site.In recent years, drones, or small unmanned aircraft systems (sUAS), have been used in geographic mapping as an alternative to traditional ground surveying. In this study, five mock monitoring wells were surveyed/geolocated using RTK GNSS. In addition, these wells were mapped using sUAS and commercial photogrammetric image processing software. This study compared the accuracy of monitoring well coordinates obtained from sUAS mapping techniques to well coordinates collected via traditional RTK GNSS equipment. The most accurate monitoring well coordinates were obtained from a single grid, 20 degrees off-nadir, flight pattern. The differences between this flight and RTK GNSS measurements was, on average, approximately 7.9 centimeters (cm) for horizontal (northing and easting) and approximately 4.8 cm for vertical (orthometric height). While not as accurate as coordinate measurements collected with RTK GNSS, data obtained from sUAS mapping techniques was accurate enough to geolocate monitoring wells for the construction of useful and meaningful topographic and groundwater contour maps. Future work may include the comparison of data collected using RTK sUAS (drones carrying an onboard GNSS RTK receiver) without ground control points (GCPs) to data collected by the methods discussed in this study.

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