Numerical modeling of slope stability in hydropower reservoir systems examined through a bibliometric and systematic review

Reservoir-level variations associated with hydropower operation can alter the hydraulic and mechanical response of adjacent slopes, while evidence linking these processes to numerical modeling remains dispersed across operational scenarios and methods. The objective of this study is to integrate the available evidence on reservoir-slope response to water-level variations through bibliometric analysis and systematic technical synthesis, examining operational hydraulic scenarios and the capabilities, applicability, and limitations of numerical and hydro-mechanical modeling approaches. The methodology comprised three phases: (i) literature search and bibliographic corpus construction; (ii) bibliometric analysis and science mapping; and (iii) systematic review and comparative technical synthesis. The search retrieved 479 records; thematic refinement yielded 420 records for bibliometric analysis, and systematic screening retained 163 studies for technical synthesis. Bibliometric analysis showed recent growth and thematic emphasis on rapid-drawdown stability assessment and numerical modeling of reservoir-level fluctuations. The technical synthesis showed that reservoir-level variation does not produce a unique mechanical response; stability depends on the transient balance between external hydrostatic support and internal hydraulic response, conditioned by permeability, drainage, geometry, structural controls, and hydraulic history. Hydraulic lag was identified in 77.9% of studies. Model applicability depended on the failure mechanism, material domain, deformation regime, and engineering output rather than on a universal hierarchy of methods. Formal geotechnical uncertainty analysis of model inputs and spatial variability was reported in only 9.2% of studies. Overall, reservoir elevation or drawdown rate alone cannot define slope condition, and model complexity should be matched to the process and engineering output of interest.