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A percolation test (colloquially called a perc test) is a test to determine the water absorption rate of soil (that is, its capacity for percolation) in preparation for the building of a septic drain field (leach field) or infiltration basin. [1] The results of a percolation test are required to design a septic system properly.
From figure 1 it is seen that 800 mm of water (or 8000 m 3 /ha) is required to bring the soil salinity down to 60% of its original value in the soil layer at 40 to 60 cm depth. When the salinity must be less than 60%, extrapolation of the leaching curve, the use of a leaching equation (see below) or a leaching model like SaltMod is necessary to ...
Groundwater recharge is an important process for sustainable groundwater management, since the volume-rate abstracted from an aquifer in the long term should be less than or equal to the volume-rate that is recharged. Recharge can help move excess salts that accumulate in the root zone to deeper soil layers, or into the groundwater system.
Coarse soils – sand and gravel – can transmit wastewater away from the drain field before pathogens are destroyed. Silt and clay effectively filter out pathogens but limit wastewater flow rates. [3] Percolation tests measure the rate at which clean water disperses through a disposal trench into the soil.
the discharge rate (Q) from the recharge rate (R) in a water balance as detailed in the article: hydrology (agriculture) the permissible long term average depth of the water table (Dw) on the basis of agricultural drainage criteria; the soil's hydraulic conductivity (Ka and Kb) by measurements; the depth of the bottom of the aquifer (Di)
Soils that have smaller pore sizes, such as clay, have lower infiltration capacity and slower infiltration rates than soils that have large pore sizes, such as sands. One exception to this rule is when the clay is present in dry conditions. In this case, the soil can develop large cracks which lead to higher infiltration capacity. [3]
It receives percolation from the soil zone above it and loses water by either infiltration into the underlying natural soil or by outflow through a perforated pipe underdrain system. New as of July 2013 [update] , the EPA's National Stormwater Calculator is a Windows desktop application that estimates the annual amount of rainwater and ...
Infiltration basins must be carefully designed to infiltrate the soil on a given site at a rate that will not cause flooding. They may be less effective in areas with: High groundwater levels, close to the infiltrating surface; Compacted soils; High levels of sediment in stormwater; High clay soil content. [6]