Mục tiêu giám sát, một khi xác định, xác định các đối tượng mục tiêu. Nó làm cho rõ ràng ai sẽ là người sử dụng thông tin và lý do tại sao thông tin là cần thiết. Nó cũng xác định các lĩnh vực quản lý và bản chất của quá trình ra quyết định mà thông tin sẽ được cần thiết | Verification of the effectiveness of pollution control strategies . by obtaining information on the degree of implementation of measures and by detection of long-term trends in concentrations and loads. Early warning of adverse impact for intended water uses . in case of accidental pollution. Increasing awareness of water quality issues by in-depth investigations for example by surveys investigating the occurrence of substances that are potentially harmful. Surveys provide insight into many information needs for operational water management. Figure Components of environmental management information systems A monitoring objective once defined identifies the target audience. It makes clear who will be the users of the information and why the information is needed. It also identifies the field of management and the nature of the decision-making for which the information will be needed. It should be recognised that the detection of trends in itself is not a monitoring objective but a type of monitoring. Only when the intended use of the trend information is specified can it be considered to be an objective. Once objectives have been set it is important to identify the information that is needed to support the specified objective. The content and level of detail of the information required depends upon the phase of the policy life cycle Figure . In the first phase research and surveys may identify priority pollution problems and the elements of the ecosystem that are appropriate indicators. Policies will be implemented for these. In the second and third phases feedback on the effectiveness of the measures taken is obtained by assessing spatial distributions and temporal trends. Contaminants may endanger human health by affecting aquatic resources such as drinking water and therefore specific monitoring programmes may be initiated to check on a regular basis the suitability of such resources. Legislation may also prescribe measurements required for certain
