Harbour protection requires monitoring the global maritime domain for building a dynamic situational picture in order to increase the ability of the decision makers to predict threat and manage operations to mitigate their possible impact. Effective situation assessment and decision making call for an integrated human-machine information environment, in which some processes are best executed automatically while for others the judgment and guidance of human experts and end-users are critical. Thus decision making in the integrated information environment requires constant information exchange between human and automated agents that utilize operational data, data obtained from sensors, intelligence reports, and open source information. The quality of decision making strongly depends on the quality of such input data as well as the information produced by automated agents and human decision makers. Designing the methods of representing and incorporating information quality into this environment is a relatively new and a rather difficult problem. The paper discusses major challenges and suggests some approaches to address this problem.