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Percolation test

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Percolation test results are not readily translated into field saturated hydraulic conductivity (K<sub>fs</sub>). However, an acceptable approximation can be made by accounting for the soil texture as well as the specific measurement and by making measurements under non-saturated conditions<ref>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>. The required calculations have been written into an easy to use spreadsheet, formatted for printing:
* Record sheets for field measurements
* Pens
* Large umbrella
===Setting up===
===Making measurements===
# To undertake the test, fill the test hole (the accurately sized test hole) with water. The water should be added carefully and slowly to avoid disturbing the soil (including the sidewall soils). When the water level falls anywhere below the 27.5 cm mark, refill the hole to the top. No recording of time needs be done for these 2 fillings.
# After the second filling, when the water level falls below 27.5 cm, add enough water to bring the depth of water to 30 15 cm or slightly more. Note that these measurements are from the base of the soil bottom (using the installed marker), not the gravel layer.
# Observe the water level until it drops to the 15 cm depth, at precisely 15 cm, commence timing, when the water level reaches the 12.5 cm depth, stop timing, record the time in minutes.
# Repeat the procedure until the last 2 rates of fall do not vary more than 2 minutes or by more than 10% (whichever is less).

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