Deformation Monitoring of Kidatu Hydroelectric Power Dam Using Geodetic Data

Abstract

The Kidatu Hydroelectric Dam in Tanzania is a critical component of the national power infrastructure, contributing approximately 36% of the country’s electricity generation. Periodic or continuous geodetic monitoring of concrete and earth dams is essential for evaluating long-term structural performance because progressive deformation may indicate changes that could affect operational safety. This study presents a long-term geodetic assessment of the Kidatu Hydroelectric Dam embankment in Morogoro, Tanzania, using observations collected over a 45-year period (1975–2020). The monitoring network comprised five reference points and sixteen object points distributed across the dam structure. Horizontal and vertical displacements were estimated across successive observation epochs to characterise deformation patterns. The maximum horizontal deformation rate was approximately 4.9 mm/yr near the pressure tunnel and decreased towards the northern section to approximately 1.2 mm/yr. Vertical velocities ranged from −2.83 mm/yr at DE05 to +0.36 mm/yr at DE15, indicating predominant settlement across the crest points and small positive vertical velocities at the lower-elevation points DE15 and DE16. Several estimated velocities exceeded their reported standard errors, whereas others were comparable with the associated uncertainties. The results therefore indicate slow, spatially variable deformation rather than providing a definitive assessment of structural safety. These findings provide baseline information for continued geodetic monitoring, structural assessment, and management of the Kidatu Hydroelectric Dam.