260-1 Geodetic Monitoring of the Robert S. Kerr Dam in Northeastern Oklahoma

Session: Advances in Geospatial Applications for Environmental and Engineering Geology (Posters)

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Abstract:

The Robert S. Kerr Dam, managed by the Grand River Dam Authority (GRDA), is a critical infrastructure for energy production and public safety in northeastern Oklahoma. To assess potential structural movement, a geodetic monitoring study was conducted from April 2021 to May 2024 using both continuous and campaign-style GPS surveys. High-precision Trimble receivers and antennas were deployed across the concrete and embankment portions of the dam. Data were processed using NOAA’s OPUS and NRCAN’s Precise Point Positioning services, and vertical displacement was further appraised using third-party InSAR data.

Northing trend lines across all stations remained stable near 0.00 cm ranging from -0.5 cm to 0.4 cm difference, indicating minimal north-south movement. Easting data ranged from -0.6 cm to 0.7 cm difference. The Easting data revealed a seasonal pattern: an initial eastward (upstream) movement of up to 0.7 cm stabilized by August 2021, followed by a westward (downstream) shift through early 2022, and a return to eastward movement in mid-2022. Similar seasonal pattern is shown from November 2023 to May 2024. Vertical trends displayed a seesaw pattern, with displacements ranging from -1.9 cm to 1.7 cm and showing the largest errors.

The embankment stations, surveyed twice during the study period, showed Northing differences up to 1.4 cm and Easting differences up to 2.5 cm. Vertical measurements exhibited larger uncertainties, limiting the ability to detect definitive movement. However, InSAR data generally aligned with GNSS vertical measurements, except during July–August 2022, when GNSS and InSAR diverged by approximately 1.5 cm.

The continuous GNSS data from the concrete portion of the dam established a reliable three-year deformation record, revealing no abnormal movement and suggesting seasonal trends likely driven by air temperature fluctuations. Campaign surveys on the embankment provided a foundation for future monitoring, though limited temporal resolution restricted seasonal analysis on the embankment. The integration of InSAR data enhanced confidence in vertical displacement assessments. This study demonstrates the effectiveness of geodetic techniques in long-term dam monitoring and supports continued observation to ensure structural stability.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6031

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