One of the first things to consider when choosing a site for a soakaway is the water table aka saturation line.
Soakaway size roof.
As a broad brush a soakaway size of 1m is sufficient to drain a roof area of approximately 50 square metres under normal conditions.
Driveway soakaway drainage technically speaking.
The two determining factors for soakaway success are the size of the area or volume of water to be drained and the percolation rate of the soil sub soil or in some sites the depth to the water table.
In most cases where the soil drains well and the roof area is less than 100m2 you will be able to construct an open chamber type soakaway as follows.
Soakaway size calculator spreadsheet this spreadsheet makes iterative soakaway design much quicker and easier allowing the designer to complete an optimal design in minutes.
A soakaway is a tank or trench where water is stored and allowed to soak into the ground rather than discharging to an outfall or sewer.
Rainwater from roof gutters conservatories driveways patios and gardens is diverted into it where it then seeps into the ground.
The size volume of the soakaway should be based on a drainage calculation this is relatively easy once a drainage percolation test is completed and you know the surface area where the water is coming from.
If water drains from roof to drive surface calculate area.
1 what is a soakaway.
If you have several different surface areas connecting to the same soakaway roof gutter conservatory patio driveway etc then more.
So 10 l x 6 2 w 30 m2 is roof area of one side of roof.
If surface water from roof drains to driveway calculate roof area.
The most common size of soakaway for residential use is 1 cubic metre 1m as this is what most local authorities seem to specify.
B a c calculate the roof area to be drained into each soakaway section plan view.