Garden remediation – poor drainage, standing water, steep falls.

DB were consulted by a young family who were upset that they were unable to make use of their garden
due to ‘extremely boggy ground’. They knew that they had drainage issues but had no idea what if anything
could be done to reduce / eliminate standing water and enable them to use their garden.
DB investigated the issue and found several contributing factors:

1. Although the garden had a ‘Basic’ French drain installed, it was clear that it had been installed to a
   poor standard and was unable to cope with the volume of water required.
2. The drain was installed too close to the surface of the lawn meaning that when it was reaching
   capacity from being unable to dissipate fast enough, it would become overloaded leaving the lawn
   in a boggy state.
3. The third issue identified was that the surrounding landscape. The lawn was laid to a fall in one
   direction with the adjacent paving slabs laid to a fall in the opposite direction creating a V Shaped
   channel where water ponded.

Fig 1: Depicting the issues

DB recommended two solutions:

1.  Increased size ‘Basic’ French drain by making it deeper / wider increasing volumetric capacity.
2.  Install a ‘proper’ French Drain to include a perforated pipe which would increase capacity but more
   importantly, could be connected into the drainage system, in this instance into a nearby swale
   which was designed to take ground & storm water.

Fig2: Recommendation 2

During conversations with the family, it was clear that they had other concerns with the garden including
the steep fall in the grassed area, DB devised a plan and recommended / carried out the following works:

1. Level the grassed area taking soil from the high point out and using it to build up the low area.
2. Build a ‘dwarf wall’ to act as a retaining wall for the soil.
3. At the lawn side of the wall, install a proper French drain.
4. At the paved side of the wall install a slotted ‘Aco channel’ to take the rain run‐off from the paving.

Standing Water coming up from Poorly installed Basic French Drain
Creating muck and dirty water in the lawn

Perforated Pipe being laid – (prior to stone – a lot of standing water, very poor condition soil).

Post Works (prior to reseeding)

1. Leveled Garden
2. Dwarf Wall
3. Invisible’ drainage under lawn
4. Aco drain along the brick wall to take water off paving

Recent Update – 4 weeks after seeding