Determination of soil permeability
The permeability of soils can easily and quickly be determined using piezometer installations according to methods outlined by Hvorslev [1951 'Time lag and soil permeability in ground-water observations' Bulletin 36, Waterways Experiment Station, MS, USA].
For uniform soil, K can be determined by both constant and falling head tests according to the following formulations:
where:
Constant head: 
Falling head: 
K= permeability cmsec-1
D = intake diameter cm
H1 = piezometer head [from fixed datum] at time t1, cm
H2 = piezometer head [from fixed datum] at time t2, cm
Hc = constant piezometer head, cm
q = supplied water inflow rate to the piezometer to maintain constant
head Hc cm3sec-1