A ditch is a shallow, narrow excavated channel used for the surface drainage of plots, roads and building sites. By collecting and carrying away surface water, ditches keep land and works dry and help control the water table.
Characteristics
- Open channel — usually a simple trench with sloping sides
- Gravity flow — water runs along a slight fall towards an outfall
- Variable size — from a small field drain to a large boundary ditch
- Maintenance — needs periodic clearing of silt and vegetation to keep flowing
Application
Where ditches are used
- Building sites — to keep the working area dry during construction
- Roads and paths — to drain the carriageway and verges
- Agricultural land — to lower the water table and prevent waterlogging
- Plot boundaries — as boundary drains between properties
Design points
- A steady fall is set so water flows to the outfall without ponding
- The formation level of works is kept above the ditch water line
- Ditches may feed an infiltration area or a piped drainage system
Related Terms
- Drainage
- Dewatering
- Formation level
- Infiltration
- Dewatering pumping
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