A Comprehensive Analysis of Dewana Dam Spillway Failure: Causes, and Consequences
Volume 12 , Issue 1 , December 2025 , Pages 10-23
Authors
Avi Ari Salahadin 1 ; Kawa Zaidan Abdulrahman 2
1 University of Sulaimani, college of Engineering, Water resources department
2 University of Sulaimani, college of Engineering, Water resources department
10.17656/sjes.101999
Keywords
Abstract
In February 2024, the Dewana Dam spillway, located in the Kurdistan Region of Iraq, experienced a critical structural failure during a moderate flood event with an estimated peak discharge of 200 m³/s. This study provides a comprehensive forensic analysis of the incident, focusing on the interplay of hydraulic, structural, and geotechnical factors that precipitated the failure. Significant damage was concentrated in the lower reach of the spillway chute, where concrete panels were uplifted and displaced, exposing a vulnerable foundation composed of friable claystone and sandstone. The ensuing erosion led to the formation of pronounced scour cavities and further destabilization of the chute structure. Findings indicate that the failure was predominantly attributed to a series of construction shortcomings. Chief among these were inadequate joint waterstop installation, the presence of pre-existing cracks, and the lack of effective seepage control all of which facilitated excessive uplift pressures beneath the slabs. Moreover, the foundation had been left untreated following an extended construction interruption and was not adequately rehabilitated prior to resumption of works, exacerbating its susceptibility to hydraulic erosion. The failure mechanism is consistent with well-documented modes of spillway chute instability found in the literature, particularly those linked to poor subgrade conditions, insufficient slab restraint, and inadequate quality assurance during construction. The Dewana Dam incident highlights the critical importance of integrated structural detailing, robust foundation treatment, and sustained construction oversight in the design and execution of spillway systems. Lessons drawn from this case offer valuable insights for enhancing the resilience of similar hydraulic structures