Hydraulic Conductivity - Amoozemeter

Parameter to be measured:

Hydraulic conductivity

Method:

Constant head permeameter: Measures infiltration rate within an auger hole up to a depth of 2 m and with extension set up to a depth of 4 m. A constant hydraulic head is kept in the auger hole which must be H/r >= 5 and the infiltration rate will be monitored until steady state flow is attained. Hydraulic conductivity will be calculated with the equation of Glover (Amoozegar, 1989b, 1993)

Equipment:

• Constant head permeameter with reservoir (with combined) Mariotte-bottle
• dissipation unit
• auger drill equipment
• measure tabe or folding meter stick
• datasheets, stop watch, torch for deep holes
• water vessels for supply

Advantages:

• in-situ measurement, no analysis of disturbed soil samples in lab
• measurement in different depths of soil profile
• easily transportable for monitoring at any location
• less water consume

Disadvantages:

• many pipes and valves - requires practice and understanding to recognise errors, set-up time
• price
• exact geometry of auger hole as specified in the equation is not often realised
• in depth up to 70 cm the measurment is complicated because of controling water level
• soils with high content of gravels and boulders would be problematic because of realsing the correct geometry of the auger hole

What to watch out for:

potential problems with

• hydrophobic soils
• heterogenous water content of soil before measurement
• strong effects from preferential flowpaths
• strong swelling/shrinking of soil
• effects of impermeable layers before stationarity is achieved
• inclined, uneven surfaces
• in loamy and clay soils the augering will smear up the soil pores which will lead to an underestimation of hydraulic conductivity

Links

Projects that used the above equipment:

• The ECHO project
• Natural Slope
• SESAM II

Other related web sites:

• How to Use an Amoozemeter for Soil Ksat movie
• Introduction to the Amoozemeter

References

• Amoozegar, A, 1989a. A compact, constant-head permeameter for measuring saturated hydraulic conductivity of the vadose zone, Soil Sci. Soc. Am. J. 53, 1356–1361.
• Amoozegar, A, 1989b. Comparison of the Glover solution with the simultaneous equations approach for measuring hydraulic onductivity, Soil Sci. Soc. Am. J. 53, 1362–1367.
• Amoozegar, A, 1993. Comments on ‘‘Methods for analyzing constanthead well permeameter data’’, Soil Sci. Soc. Am. J. 57, 559– 560.
• Amoozegar, A, 2005. Amoozemeter, in: Lal, R. Encyclopedia of Soil Science, Second Edition.
• Elrick, DE, Reynolds WD, 1992. Methods for analyzing constanthead well permeameter data, Soil Sci. Soc. Am. J. 56, 320– 323.
• Elrick, DE, Reynolds, WD, 1992. Methods for analyzing constanthead well permeameter data, Soil Sci. Soc. Am. J. 56, 320– 323.
• Elsenbeer, H, Newton, BE, Dunne T, de MoraesJM, 1999. Soil hydraulic conductivities of latosols under pasture, forest and teak in Rondonia, Brazil. Hydrol. Process. 13, 1417-1422.
• Sobieraj, JA, Elsenbeer, H, Coelho, RM, Newton, B, 2002, Spatial variability of soil hydraulic conductivity along a ropical rainforest catena, Geoderma 108, 79–90.
• Zigler, AD, Negishi, JN, Sidle, RC, Noguchi, S, Nik, AR, 2006. Impacts of logging disturbance on hillslope saturated hydraulic conductivity in a tropical forest in Peninsular Malaysia. Catena 67, 89 – 104.