The stability of the earthen dams is significantly influenced by their saturation characteristics particularly the dissipation of matric suction above the phreatic surface. This paper deals with analysing the impact of blocked internal drains on the stability of an impoundment dykes. 2D finite element analysis in SIGMA/W and SLOPE/W modules of GeoStudio is employed for the study purpose. A coupled hydro mechanical approach is adopted to simulate the construction phase, consolidation phase and rainfall infiltration phase, allowing to assess the stability of dyke both before and after the exposure to rainfall, with and without blocked drain scenarios. The hydrological condition considered in the analysis is the daily rainfall. Results from simulations indicate that when drains function effectively, dykes of an impoundment remain stable. However, in instances of drain blockage, a surge in phreatic surface within the dyke result in instability. These findings underscore the critical importance of drainage systems in maintaining the structural integrity of impoundment dykes, especially in the context of rainfall-induced infiltration. This research emphasizes the need for proactive measures to prevent drain blockages and mitigate associated risks. Ultimately, this study enhances our understanding and management of embankment performance under varying hydrological conditions, informing practices that promote resilience and safety in civil engineering projects.