Do you have a path that holds water after heavy rainfall?

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There is a cheap and simple solution for fixing it...

Where a path surface is lower than the surrounding ground, there will be a tendency for raised verges to form between the path and the edge of any side ditch. Raised verges can hold back surface water creating standing water on the path, particularly after heavy rainfall. This path drainage problem can be easily remedied by installing a short or long 'V' shaped open ditch called a 'Grip' (also known as a Lett). Grips can be installed through the high verge to allow surface water to drain into a side ditch easily and quickly.

Function of Grips

Grips drain standing water on a path surface into a side ditch, or onto site areas where the water can soak away into the ground. They are relatively cheap and simple to install, but do require regular inspection and maintenance to keep them functioning properly. Grips should, however, be avoided if the verges are used for horse riding - can create a trip hazard.

Positioning of Grips

Grips are generally positioned at the lowest points along the path edges, where water stands on the path surface after heavy rainfall. On level paths, grips can be positioned about 15 to 30 metres apart.

grip

 

 

 

 

 

 

 

 

 

 

 

 

Construction of Grips

A grip is a simple drainage feature comprising of earth or turf base and sides. Grips should be least 300mm deep and 300mm wide at the base and least 450mm - 500mm wide at the top with 45º sloping sides. These dimensions will provide plenty of room for clearing out the channel with a spade.

Step 1

Starting at the side ditch dig a 'V' shaped ditch, working backwards through the raised verge, towards the path - maintain a good draining fall along the dug ditch from the side ditch to the path edge.

Aim to:

  • Keep the ditch deep and wide enough - angle the sides to 45º.

  • Keep the ditch bottom level and even whilst maintaining a constant draining fall towards the side ditch - avoid creating low and high points by digging too deeply or too shallow.

  • Keep the ditch straight to allow good water flow to side ditch or site area where the water will soak away into the ground.

grips2

Step 2

Check the ditch base is deep and wide enough and the sides are angled back for stability. If the sides are not angled back when the ditch is initially dug, do it afterwards. Give the ditch base a final work over to achieve a finished level and even bottom with a good drainage fall, free of any loose earth, stones or rocks, to allow water to flow easily and quickly along the ditch to the side ditch.

Step 3

Where high water flows are expected, use available turf removed from the grip line to turf the ditch base and sides to protect them from water erosion. This will also reduce the visual impact of the grips through the raised verge. Excess turf and excavated earth should be landscaped on site, and out of sight.

Maintenance of Grips

The following maintenance tasks should be carried out to all grips on a regular basis:

  • Check and clear out silt, leaf litter and other debris from grips. Dispose of arisings carefully, tidily and out of sight. Ensure it does not end up back in a grip!

  • Check for scouring or erosion at inlet and outfall ends of grips. Remove any obstructions that may be causing the erosion or restricting water flowing out.

  • Check for scouring of grip bases and undercutting of sides. Remove any obstructions that may be causing the scouring or restricting water flow along grips. Regrade bottom of grip bases where water is standing and not flowing. Widen and re-angle the sides of grips where undercutting has occurred or is likely, until stable.

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