Water Resources Assessment is more than conducting a simple water balance, it requires a dynamic approach to the spatial and temporal variability of resources, and of demands and pressures put on them by various societal requirements (water supply, industry, agriculture, environmental protection, etc.).
WRA must support the provision of information and data to decision-makers enabling them to implement evidence and fact-based policies for both long-term planning to respond to short-term emergencies, based on the knowledge of status and trends of the resource.
WRA must also be flexible and adaptable to take into account the social, economic and environmental context, the skills and resources (human, financial) of the stakeholders (especially those involved in data monitoring and information generation), and the availability and quality of data. It is therefore important that they employ extensive consultative processes involving both users and providers of information to define requirements and the extent to which they can be satisfied
To support this broad interpretation of the WRA concept the whole value chain has to be addressed, from monitoring, to product development, to information delivery. In particular, existing WMO regulatory and guidance material refers to standards and recommended practices addressing several of the WRA process components, and the remaining gaps are being filled through the development of relevant material.