A gracht is a dug watercourse, usually with straight, walled or revetted banks, that runs through or around a town, estate or fortification. From the earliest times, grachten have served several functions at once: water management, defence, transport and representation.
Functions of a gracht
- Water management — grachten carry off rainwater and surplus water and keep the groundwater level up
- Defence — a castle moat or town moat formed an obstacle around a castle or town
- Transport — in the past goods were carried along the grachten right up to the warehouses
- Representation — canal houses and water features define the image of cities such as Amsterdam, Utrecht and Delft
Construction aspects
The banks of a gracht are often held by a quay wall or revetment. This structure has to resist earth pressure and withstand fluctuating water levels. Buildings along a gracht generally stand on a pile foundation, because the soil there is soft and waterlogged.
Maintenance and management
- Grachten silt up and have to be dredged periodically
- Quay walls and revetments require maintenance against subsidence and decay
- The water level is managed by the water authority, often with pumping stations and weirs
Related Terms
- Water management
- Revetment
- Quay wall
- Pile foundation
- Pumping station
Want to learn more about construction terms? Visit the full knowledge base at fredsdiyplans.com.