INTERA was awarded a contract from the University of Mississippi to support the development of GIS-based database and vulnerability analysis tools for Mississippi groundwater, surface water resources, and dams. The project scope includes developing complete inventories of critical infrastructure and key resources and performing vulnerability assessments to identify potential areas of weakness and provide guidance for prioritizing vulnerability reduction decisions. A two-tier risk assessment approach for determining the vulnerability of groundwater, surface water, and dams is being developed and applied at the hydrologic basin scale. A Tier 1 vulnerability assessment using simple indexing and weighting methods is being conducted to rank resources. This assessment is based on the susceptibility of the resource to natural and anthropogenic threats and the economic, public health and safety, and security consequences associated with the threats. Water resources and dams, with high vulnerability based on the Tier 1 analysis, will be subjected to a Tier 2 risk assessment that includes general and specific threat scenarios evaluated stochastically to quantify vulnerability in the presence of uncertainty. The work is being performed by a project team consisting of the University of Mississippi, INTERA, the Mississippi Department of Environmental Quality, and the Mississippi Department of Health.