@ Babafemi, Percolation rate (ml/min) = amount of water (ml) / percolation time (min). For example, If 200 ml of water is percolated through the soil sample in 40 min. Then the rate of percolation is 200/40 = 5ml/min. Percolation is the movement of water through soil, and the percolation rate is the speed at which that movement occurs. Actually, percolation is the downward movement of water through pores and other spaces in the soil due to gravity.

Babafemi Sanyaolu One rapid field method to estimate the percolation rate is this: carefully dig a hole (square or round) in the ground or soil using a knife down to the soil depth you are interested in. Then fill the hole with water of known volume and observe until the water disappears at the bottom of the hole. Percolation rate will then be the amount of water added (ml) divided by the time required (min) similar to the calculation by J. C. Tarafdar . To get a good estimate, several trials or holes are necessary.

https://www.indiawaterportal.org/articles/how-measure-water-percolation-rate

Percolation rate means the time expressed in minutes per inch required for water to seep into saturated soil at a constant rate during a percolation test. https://www.lawinsider.com/dictionary/percolation-rate

Note: there is a difference between percolation and infiltration rates. While infiltration relates to non saturated soil, percolation occurs in a saturated soil.

Start by looking at the ground. Is the soil homogeneous or variable in character? The more consistent it is the easier the work. If it is a thin layer of soil on top of rock the infiltration could be due to fissures in the rock. Although vertical infiltration is often what is measured by simple tests, in practice horizontal infiltration is also common in most soils.

The more site investigations - trial holes - you use the better will be your estimate. However, all measures of infiltration can have a massive error due to the inconsistency of real ground. Laboratory tests using tubes give accurate results for the sample, but may not translate well for a real drainage area.

A simple indicator of drainage is the plants that occur naturally on the site. If they are boggy plants the soil will not be free draining, if they are drought resistant plants it could be a sandy soil that drains rapidly. Asking a gardener could be a quick way of finding how well an area of soil drains.

Percolation rates are estimated using vertical temperature profiles from sequentially deeper vadose environments, progressing from sediments beneath stream channels, to expansive basin-fill materials, and finally to deep fractured bedrock underlying mountainous terrain. Deep percolation rates are normally estimated from a water balance.

Have a look at these articles:

Article An analytical solution for estimating percolation rate by fi...

Article Comparison of methods to estimate deep percolation rates

https://journals.lww.com/soilsci/Abstract/1986/11000/AN_ANALYSIS_OF_THE_PERCOLATION_TEST_BASED_ON.9.aspx

Thank you

Ankur

Dear Sanyaolu,

Kindly have a look at below mentioned links to estimate percolation rate:

https://www.nature.com/articles/s41598-020-58333-8

https://www.mdpi.com/2073-4441/11/7/1457/pdf

https://www.thurstoncountywa.gov/sw/swdocuments/Methods%20for%20Determining%20Infiltration%20Rates%20Checklist.pdf

https://pubs.usgs.gov/wsp/1544f/report.pdf

http://www.fao.org/3/S8684E/s8684e0a.htm

http://content.rcflood.org/downloads/NPDES/Documents/LIDManual/Appendix%20A_Infiltration_Testing.pdf

Hello @ Babafemi

You can use an analytical approach using Temperature-Profile Methods to estimate percolation rates. The following studies may be Article An analytical solution for estimating percolation rate by fi...

https://pubs.geoscienceworld.org/vzj/article/2/1/12/111738/Temperature-Profile-Methods-for-Estimating

Article The Use of Streambed Temperature Profiles to Estimate the De...

cheers