Fresh surface water balance for the Netherlands
In the water balance for the Netherlands, the inflow and outflow of river water are very important. The inflow of water from the Rhine is a particularly important factor.
| Dry | Average | ||
| year | year | ||
| billion m3 per year | |||
| Inflow | 67 | 108 | |
| Precipitation | 21 | 27 | |
| Rhine | 42 | 70 | |
| Maas | 4 | 8 | |
| Other rivers | 2 | 3 | |
| Outflow | 67 | 108 | |
| Evaporation | 21 | 18 | |
| Consumption | 6 | 3 | |
| Rivers | 41 | 86 | |
| Source: RIZA. | RIVM /EDC/Oct03 | ||
River water is the main determinant for the water balance
In the water balance for the Netherlands, the inflow and outflow of river water are particularly important, alongside precipitation and evaporation. The figures show that the inflow via the Rhine is crucial.
Note on water cycle
The action of the sun causes water to evaporate out of oceans, seas and lakes. Some of the water moves through the atmosphere and reaches land, either as vapour or in the form of precipitation. Most precipitation then evaporates, flows rapidly into rivers or penetrates into the soil. In time, that groundwater will once again return to the surface water.
Stocks of groundwater and surface water not included in the balance
The stocks of groundwater and surface water in the Netherlands have been left out of the balance. Only very crude estimates are available for these quantities. Neither are the underground inflow and outflow of ground water included.
Note on dry, wet and average years
The figures for a dry year are the average of a number of years that can be described as dry. Examples are 1949, 1959, 1976, 1995 and 1996. This classification is based on the growing season (1 April - 30 September) and not on the winter season. As a result of a change in the source of the data, the figures are different from those stated in the previous Compendium. The figures for an average year relate to 1967.
