Check List For Garden Drainage Project.

Check list for a small garden drainage project. For further information on carrying out a garden drainage project click here
•    make sure you have determined where the drainage water is going to drain to. Ideally into a surface water drainage system i.e your houses down pipe drain through a simple silt trap. Determine the level this will be at as the land drains must be as the same level at this or are laid so they have a fall into the silt trap.
•    A silt trap is a simple box normally built from bricks that the drainage water flows into and out of and in doing so silt in the water drops to the bottom of the box
•    in a small garden do not worry to much about getting the drains to fall as long as they are roughly falling or level this will do. The fall is more critical on a larger drainage scheme. You can always leave the drains open until it rains or try adding some water from a hose to make sure the drains flows.
•    Once the drains are installed to key is to make sure the water can reach the drain. This can be achieved by adding grit or sharp sand to the area and digging it in to a depth of 70 to 100 mm this will create a sandy zone where surface water can travel sideways to reach the drains or drain channels. If its an existing lawn this can be achieved by top dressing in the spring and autumn with a sandy top dressing to build up a free draining layer.
•    If the area has been wet or is on heavy clay you are best to grow the finer grass species as they will grow slower and require less cutting. One such turf is Rolawn medallion turf.
A sample materials list for a small garden drainage scheme
•    Roll off land drainage pipe 75/80mm normally in 25 meter coils
•    20mm clean gravel or stone in 25kg bags ( number depends on depth of drains )
•    25 engineering bricks to build small silt trap
•    One bag or cement five bags of sand two bags of concrete ballast to create base for silt trap
•    trenching spade so you can dig narrower trenches saving time and material costs
•    Ton bag of sharp or grit sand