Water resources: long-term annual average
methods, notes and classification
The minimum period taken into account for the calculation of <b>long term annual averages</b> is 20 years.<br><b>Actual evapotranspiration</b> is the volume of water transported from the ground (including inland water surfaces) into the atmosphere by evaporation and by transpiration of plants.<br><b>Internal flow</b> is the total volume of river run-off and groundwater renewal generated, in naturalconditions, exclusively by precipitation into a territory. The internal flow is equal to precipitation less actual evapotranspiration.<br><b>Actual external inflow</b> is the total volume of actual inflow of rivers and groundwater coming from neighbouring territories.<br><b>Total fresh water resources</b> is the total volume of water that is additionally available due to internal flow and external inflow.<br><b>Total actual outflow</b> is the total actual outflow of rivers and groundwater into the sea and into neighbouring territories.
Methods 
Explanatory Notes 
Variables