A Detailed Safety and Risk Assessment of Massingir Dam

Abstract

At the request of the Mozambican Directorate of Water Program (DNGRH) and as part of the National Climate Resilience Program, a study aimed to evaluate the current safety of the Massingir dam and downstream valley was developed by the Consortium COBA/LNEC/SALOMON. The objectives encompassed a range of activities, designed to ensure a thorough assessment and enhancement of dam safety, a critical issue to guaranty the integrity and reliability of this key water infrastructure in Mozambique. In this paper, structural and hydraulic-operational safety results are presented, as well as its adaptationto the new Mozambican dam regulations. The Massingir Dam, the second largest in Mozambique, is situated on the Elephants River, a tributary of the Limpopo River, This 4,500-meter-long and 47-meter-high earthfill dam primarily supports irrigation in the Lower Limpopo Valley. Concluded in 1976, Massingir dam has a history of anomalous structural and hydraulic-operational behaviours and has already had several rehabilitation interventions. The study involved a comprehensive evaluation of dam performance, including a review of operational procedures and detailed site inspections. It analyzed existing monitoring data and assessed current safety conditions. A thorough risk assessment identified both structural and non-structural mitigation measures. The comprehensive assessment approach taken for the Massingir dam revealed strenghts and weaknesses in currrent dam practices. By implementing the recommended measures, the safety and functionality of this dam will be signficantly enhanced. Key lessons underscored the critical need for regular monitoring and robust safety assessment procedures. This will contribute to the overall resilience and security of the region’s water infrastructure and ensure the safety of populations living downstream.