(Table 1) Chloride concentrations in water obtained from observation wells on Helgoland Dune, North Sea

The hydrogeological conditions are unfavourable for a sufficient supply of drinking-water. The small size of the catchment area, the large hydraulic gradient inside the steep 'Buntsandstein'-cliff and the low geodetic level of the 'Dune Island' and the foreshore at the eastern foot of the cliff do not allow the formation and recharge of a sufficiently exploitable geodetic freshwater dome over the underlying saltwater. This means that until recently the provision of sufficient drinking-water for the island's inhabitants, for its garrison as well as for visiting ships was a problem. This problem has now been solved by the desalination of seawater.

该区域水文地质条件不利于获取充足的饮用水供应。汇水区（catchment area）面积狭小、陡峭的斑砂岩（Buntsandstein）崖壁内部水力梯度（hydraulic gradient）极大，且沙丘岛（Dune Island）与崖壁东麓前滨地带的大地测量高程偏低，上述因素均无法在下部咸水层之上形成并补给可充分开采的测压淡水丘。这意味着直至近期，为岛上居民、驻军以及到访船只提供充足饮用水始终是一项难题。如今，该难题已通过海水淡化（desalination）技术得到解决。