Percolation test
SOIL PERMEABILITY TEST – PERCOLATION TEST
The feasibility of an infiltration system under given ground conditions can be determined using a percolation test. The test should be carried out at the planned location of the infiltration system. The works should begin with the excavation to a depth of about 0.5 – 1 m (depending on the depth of the infiltration system). The following steps should be taken in the resulting excavation:
- make a hole measuring 30 cm x 30 cm and 15 cm deep (the walls and bottom in the made hole should not be smoothed, loose soil should be removed from the excavation)
- pour 10 l of water into the hole in order to moisten the soil
- after moistening the soil, pour 12.5 l of water into the hole and measure the soaking time expressed in minutes
- determine the type of soil and calculate the maximum hydraulic load of soil qmax (using the filtration coefficient according to current standards), i.e. how many litres per day can be absorbed by 1 m2 of soil.
| SOAKING TIME OF 12.5 LITRES OF WATER (MIN) | SOAKING CAPACITY (MIN/CM) | TYPE OF SOIL | PERMEABILITY | RECOMMENDED TYPE OF INSTALLATION |
|---|---|---|---|---|
| <20 | <1,4 | all-in aggregate, gravel, coarse sand | A – very good | infiltration drainage with retaining layer |
| 20-30 | 1,4 – 2,1 | medium and fine sand | B – good | infiltration drainage |
| 30-180 | 2,1 – 12,8 | loamy sand, sandy loam | C – moderate | infiltration drainage with support layer |
