Jump to: navigation, search

Percolation test

238 bytes added, 10 months ago
no edit summary
[[File:Perc_test.png|thumb|Schematic of percolation test setup]]
A percolation test is one way of determining a [[design infiltration rate]]. If a site disturbance must be minimized, this test can be performed in a small augered well. Adding a [[permeameter]] may speed up analysis.
Percolation test results cannot be translated into field saturated hydraulic conductivity (''K<sub>fs</sub>'') by simple manuipulation of the units. However, an acceptable approximation can be made by accounting for the soil texture and by making measurements under non-saturated conditions<ref name = 'Reynolds'>Reynolds, W.D., Galloway, K., and Radcliffe, D.E. (2015). "The relationship between perc time and field-saturated hydraulic conductivity for cylindrical test holes.", National Onsite Wastewater Recycling Association (NOWRA) 2015 Onsite Wastewater Mega-Conference, Virginia Beach, VA, USA, November 3-6, 2015</ref>.
# Place 5 cm of clean fine gravel in the bottom of the hole. If the sidewalls are likely to collapse, use a paper basket to support the sidewalls.
#Place a piece of white plastic or similar provided with clear marks at 12.5 and 15 cm (5" and 6") from the bottom of the test hole prior to adding the gravel. For greater accuracy a float and pointer arrangement can be set up.
# If the soil contains considerable amounts of silt or clay, and certainly for any soil with “clay” as part of the [[Soil groups|texture description]], the test holes should be pre-soaked before proceeding with the test. Pre-soaking is accomplished by keeping the hole filled with water for 4 hours or more. The water should be added carefully and slowly to avoid disturbing the soil (including the sidewall soils). The test should be carried out immediately after pre-soaking;
===Making measurements===

Navigation menu