Key:water_system
 water_system
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| Description |
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The water system that a particular body of surface water or waterway belongs to in terms of water management 
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| Group: water management |
| Used on these elements |
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| Useful combination |
| See also |
| Status: in use |
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Describes the water system that a particular body of surface water, waterway or tract of land belongs to in terms of water management. An island (and the land and water that are part of it) itself can a boezem (where the land and water in typically lies higher than te surrounding water) or a polder (where the land and water in it typically lies lower than the surrounding water)
Normally water eventually flows down to the sea, possibly partly / temporarily interrupted by weirs or sluices. In some instances however, especially in low lying countries and river deltas, separate artificial hydrological entities have been made, meaning it has no connection with outside water other than through manually operated devices. In these cases water typically is being moved up to the next system instead of down.
Values
- water_system=outside_water Water that eventually flows down to the sea (possibly interrupted by weirs or sluices).
- water_system=boezem An intermediate water level, separated from -and typically lower than- the outside water. The boezem (no English translation available at this moment) collects the water pumped up from polders and which is subsequently pumped up to open water (or drained by opening sluices at low tide). The boezem is typically the system in which inland nautical navigation takes place.
- water_system=polder Low-lying tract of land enclosed by dikes that form an artificial hydrological entity from the boezem, with water inside it that has a level that is typically lower than the boezem. While in the boezem waterways are typically navigable for small boats / canoes, in the polder only the larger canals are wide and deep enough for practical navigation, even for canoes. Going from boezem to polder water means using a lock (which is typically not available) or portaging. Nevertheless some popular water sports areas are polders, that can be reached by boats from the boezem through locks.
See also
- Boezem on Wikipedia
- Polder on Wikipedia
- Water board (Netherlands) on Wikipedia
Mapping examples
- An example of a current map (Rijnland) that shows the difference between boezem en polder for both water and land within a single boezem-system
- An example of a historical map (Hoekwater) that shows different boezem-systems and the polders within it