Dealing with existing drainage

PDF Print

When upgrading an existing path, or creating a new one, it is likely that you will encounter the existing drainage, especially if the path is on disused railway line or land used for agriculture. This may be a few drains and ditches. In the case of disused railway lines or agricultural land, it may be a comprehensive system of drains.

Existing drainage should be located and inspected to determine if they are working effectively and are adequate for your needs. Make sure that existing sub-surface field drains, discharging excess water from the soil into perimeter ditch, are not damaged during your explorations. It is best to allow for some budget when costing a project, just in case replacement of existing drainage is required. Further investigations and trial digs are best undertaken when ground preparation works are being carried out, before any path construction starts, when plant and machinery are available on site. When designing any additional drainage, do not exceed the capacity of the existing drainage system, if new drainage is connected into it.

Hints on locating existing drainage:

  • Ask the current (and past) landowners on the whereabouts of drainage systems on their land

  • Look for signs of sub-surface clay pipe drains (or modern plastic perforated pipe) on the field surface e.g. standing water on low lying areas

plastic perforated pipe

Perforated plastic pipe...

  • Look for any obvious linear strips of crops, grass or other vegetation taller than the surrounding ground which could indicate a drain

  • Look and listen for fast flowing water running along drains and coming out of pipe outfalls

pipe outlet fast flowing water

Piped culvert outlet...

  • Carefully dig inspection trenches where the line of a drain may be

inspection trench

Inspection trench...

  • You could use divining rods to try and identify the line of a drain
  • Look for old clay pipe drains running through railway cuttings which may have inspection pits at regular intervals that allow access to cleanout blocked drains

<< Back to top

© 2014 Paths for All - Registered Scottish Charity No: SC025535, Company Limited by Guarantee No: 168554 inc. 19 Sept 1996 at Companies House, Edinburgh