Disaster impact assessments are crucial for understanding disasters and effective disaster prevention. Deciding how to respond to disasters cannot be efficient without considering the disaster’s social and economic impacts. Among all types of disasters, drought and flood induce the largest human and economic cost. Interbasin transfer is a commonly used strategy to overcome the mismatch between water availability and water demand, and enhance economic development. The researches present within this dissertation discuss how can we develop an efficient economic impact model or models which can take into consideration sector vulnerability and resiliency strategies in response to extreme climate events, to assist decision makers in devising response strategies. The first and second studies in this dissertation investigate methods to assess the economic consequences of drought induced water restriction and the economic consequences of flood impact in public water supply systems. Drought and flood induce water outage, and cause substantial impacts in public water supply systems. However, researches and tools which assess drought and flood impact in water supply systems are uncommon. We adapt previous work on economic consequence assessment in the event of water services disruption to evaluate the economic impact of water restrictions resulting from extended drought conditions, and water contamination and outage resulting from flood conditions. These two models focus on all commercial and industrial economic sectors across multiple basins using a continuous dynamic social accounting matrix approach.The third study in this dissertation investigates the interbasin transfer impact to the basin(s), with a focus on agriculture production, and discusses the necessity to establish a state-level interbasin transfer regulation in Alabama. A framework for comprehensive impact assessment of interbasin transfer is developed in this dissertation. The interbasin transfer research reviews four representative interbasin transfer projects, concludes the triggers of interbasin transfer projects and impacts in economic, hydrologic, ecological, and social systems. The relation between irrigation and agriculture production is simulated with AquaCrop. Three states’ interbasin transfer regulations and acts are studied. Results indicate the required processes to establish a state-level interbasin transfer regulation and the focuses of future researches.