The Mosul dam was constructed in 1982 in order to provide hydro power and water resources for agricultural purposes in Iraq. It also served the very important function of controlling significant periodic flooding of the Tigris river that negatively affected the country. The dam is the biggest in Iraq with a reservoir of 11.1 billion cubic meters and a 113 meters high and 2.21 kilometers long earth embankment. It was finalized and became operational in 1985 and concerns were immediately raised regarding the structural integrity of the soil holding the dam. The dam is built on soft rock foundation containing gypsum and anhydrite (both soluble materials) in addition to limestone and pre-existing limestone caves that act to speed up the dissolution process.The humanitarian community in Iraq has been closely following the possibility of a dam collapse;an UNDAC team was mobilized in April 2016 to discuss with all relevant stakeholders and analyse different flooding scenarios in order to predict the impact of the flood levels. The most common scenario being used is for a breach to occur at a water reservoir level of 315 meters above sea level(MASL). In such circumstances, the flooding will reach Mosul city in 2.35 hours with an initial wave height of21 meters, whereas water will reach Baghdad in3to 4days (83 hours) with an initial wave height of 7.5 meters. Based on calculations made by the Logistics Cluster to determine the population in need, it is likely that up to 8 million people could be impacted, with more than 4 million potentially displaced as a result of the flood waves. The Logistics Cluster is building on previous studies and missions to determine the cluster-specific emergency preparedness and response plan to ensure it will be able to provide the needed logistics support and services to the humanitarian community.In case of a Mosul dam fault resulting in a major humanitarian emergency, the Logistics Cluster will aim to provide and facilitate common storage,including prepositioning in strategic areas and emergency transport to the humanitarian community,and ensure a coordination and information management role to maximise the use of available resources in-country and establish a more coordinated and cost-effective operational approach and humanitarian response.