Groundwater situation in the Netherlands, 1950-1990
Changes in shallow water table (left-hand figure)
In large sections of the High Netherlands, the shallow water table has fallen by 20 to 40 centimetres. There have even been local falls of 40 to 120 centimetres (source: Alterra; Sluijs, et al., 1989). This fall has been caused by changes in water management for agriculture and horticulture since the 1950s. The local large falls are probably caused by a combination of changes for agriculture and horticulture, and increasing groundwater extraction, for example for drinking and industrial water supplies.
Influence of rural land parcelling schemes on the shallow water table
Mechanisation and the increasing scale of agricultural operations have led to many reparcelling projects and land development schemes since the 1950s. The associated changes to the water system mainly involved a lowering of the level, the improvement of the drainage and, in the case of higher ground, the introduction of water from elsewhere. This led to the lowering of the water table or reduced upward seepage, with the desiccation of nature as a result.
Changes in deeper water table (hydraulic gradient) (right-hand figure)
The average hydraulic gradient of deeper groundwater in the Netherlands fell in recent decades by more than 30 centimetres (Kremers and Van Geer, 2000). The fall began in the mid-1950s and is found virtually everywhere.
It is probably the result of the increase of groundwater extraction. In 1950, the amount of drinking water abstracted for drinking water was about 250 million m3/year; by about 1998, that had increased more than threefold to approximately 800 million m3/year. Groundwater extraction for industrial purposes reached a peak in the 1970s of approximately 500 million m3/year and has now fallen back to the level of 1950, approximately 200 million m3/year.
For the sake of completeness, it should be pointed out that there is of course an interaction between the fall in the shallow water table caused by the fall in the surface water level and the fall of the hydraulic gradient of the deeper groundwater caused by water extraction.
