Typical examples include the assessment of third party impacts, environmental impact assessments or existing users foregoing use (for instance, in situations where the catchment is closed). An inventory of available water resources is produced and existing water uses and demands are identified. Water resources assessment methods have been developed for the whole Spanish territory, as well as simulation water resources models that take into account: conventional and non-conventional water resources, environmental flows, water demands, hydraulic infrastructure, water use priorities and exploitation rules in order to establish water allocations and reserves.