A lawn with poor drainage can develop a multitude of problems including fungal, disease, weed infestation and even lead to your grass dying.
Getting your lawns drainage correct before installing a new lawn can save you a lot of headaches like these down the track. But if you already have a lawn and you have a few low spots where water is pooling there are some things you can do.
First thing you can try is aeration.
Aerating your lawn will help to improve permeability allowing water to be absorbed better. If your drainage issue is quite severe though, regular aerating may not be enough to stop water from pooling.
Topdressing to improve soil profile.
If your soil base is compacted and has a high proportion of clay, regular aerating combined with topdressing will help to improve the soil profile and better allow for water absorption, but this should only be done during the warmer months of the year. It would also be advisable to spread gypsum which will help the water to seep down deeper.
If the problem continues to persist however even after only a light to moderate amount of rain, you will need to look at a more permanent solution to your drainage issues.
A French drain is a common solution that involves digging a trench with at least a 2-4% slope for the excess water to flow into. For a 1-metre trench for example you would need the slope to be at least 2cm from the highest point to the lowest. At the bottom of the trench is a perforated pipe that is covered over with gravel.
A drywell is a large hole in the ground filled with gravel, with an inlet line coming from a drain, downpipe or French drain coming into the pit. A drywell will help to transfer surface water deeper into the subsoil.
Dry Creek Bed
A dry creek bed is a trench that usually follows along a channel or the natural fall of the surface, filled with gravel or stones. This helps to control the water flow, diverting it away from low spots and preventing erosion through run off. Dry creek beds are becoming more common as they provide an interesting element for landscaping and also provide a practical drainage solution.
There are many other options available to suit different situations, so if you are uncertain on what drainage option is the best solution for your area, it’s best that you bring in an expert.