| Year | Mean annual Recharge | Methods used | Source |
| 1995 | 8 | Chlorine Mass Balance (CMB) | Vegter, 1995 |
| 2011 | 4 | Chlorine Mass Balance (CMB) | Holland, 2011 |
| 2011 | 12.3 | Water-Table Fluctuation (WTF) | Holland, 2011 |
| 2018 | 12.04 | ArcGIS | This study 2018 |