The term new groundwater formation as used here refers to the process by which groundwater is formed from the percolation of precipitation water. The amount of new groundwater formation differs from the amount of percolation water formation. It is reduced, by comparison with the percolation water rate, by the proportion of interflow, i.e., that portion of the runoff that flows into the receiving streams from the near-surface layers of soil. For these reasons, a new groundwater formation map, Map 02.17, has been drafted in addition to the percolation (Map 02.13.2) and the total runoff (Map 02.13.3).
Knowledge of the level of new groundwater formation is particularly important for long-term and sustainability use of groundwater resources and furthermore for the estimate of the potential danger of immission of pollutants from the non-saturated zone to the groundwater. The amount of new groundwater formation shown in Map 02.17 as the new groundwater formation rate (mm/year) by block section, is an important initial parameter for the derivation of the dwell time of the percolation water in the groundwater overburden (Map 02.16).